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reuvenlax pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
     new e039ca2  Merge pull request #14136: [BEAM-11648] Add conversion 
utilities for BigQuery Storage API sink
e039ca2 is described below

commit e039ca28d6f806f30b87cae82e6af86694c171cd
Author: reuvenlax <re...@google.com>
AuthorDate: Fri Mar 5 08:07:41 2021 -0800

    Merge pull request #14136: [BEAM-11648] Add conversion utilities for 
BigQuery Storage API sink
---
 .../io/gcp/bigquery/BeamRowToStorageApiProto.java  | 336 +++++++++++
 .../beam/sdk/io/gcp/bigquery/BigQueryUtils.java    | 221 +------
 .../beam/sdk/io/gcp/bigquery/CivilTimeEncoder.java | 648 +++++++++++++++++++++
 .../io/gcp/bigquery/TableRowToStorageApiProto.java | 304 ++++++++++
 .../gcp/bigquery/BeamRowToStorageApiProtoTest.java | 391 +++++++++++++
 .../sdk/io/gcp/bigquery/BigQueryUtilsTest.java     | 260 ---------
 .../bigquery/TableRowToStorageApiProtoTest.java    | 312 ++++++++++
 7 files changed, 1993 insertions(+), 479 deletions(-)

diff --git 
a/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/BeamRowToStorageApiProto.java
 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/BeamRowToStorageApiProto.java
new file mode 100644
index 0000000..816cbe9
--- /dev/null
+++ 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/BeamRowToStorageApiProto.java
@@ -0,0 +1,336 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.io.gcp.bigquery;
+
+import com.google.protobuf.ByteString;
+import com.google.protobuf.DescriptorProtos.DescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Type;
+import com.google.protobuf.DescriptorProtos.FileDescriptorProto;
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.DescriptorValidationException;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.FileDescriptor;
+import com.google.protobuf.DynamicMessage;
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+import javax.annotation.Nullable;
+import org.apache.beam.sdk.schemas.Schema;
+import org.apache.beam.sdk.schemas.Schema.Field;
+import org.apache.beam.sdk.schemas.Schema.FieldType;
+import org.apache.beam.sdk.schemas.Schema.LogicalType;
+import org.apache.beam.sdk.schemas.Schema.TypeName;
+import org.apache.beam.sdk.schemas.logicaltypes.EnumerationType;
+import org.apache.beam.sdk.schemas.logicaltypes.SqlTypes;
+import org.apache.beam.sdk.values.Row;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.annotations.VisibleForTesting;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Functions;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableMap;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Iterables;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Lists;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.primitives.Bytes;
+import org.joda.time.ReadableInstant;
+
+/**
+ * Utility methods for converting Beam {@link Row} objects to dynamic protocol 
message, for use with
+ * the Storage write API.
+ */
+public class BeamRowToStorageApiProto {
+  // Number of digits after the decimal point supported by the NUMERIC data 
type.
+  private static final int NUMERIC_SCALE = 9;
+  // Maximum and minimum allowed values for the NUMERIC data type.
+  private static final BigDecimal MAX_NUMERIC_VALUE =
+      new BigDecimal("99999999999999999999999999999.999999999");
+  private static final BigDecimal MIN_NUMERIC_VALUE =
+      new BigDecimal("-99999999999999999999999999999.999999999");
+
+  // TODO(reuvenlax): Support BIGNUMERIC and GEOGRAPHY types.
+  static final Map<TypeName, Type> PRIMITIVE_TYPES =
+      ImmutableMap.<TypeName, Type>builder()
+          .put(TypeName.INT16, Type.TYPE_INT32)
+          .put(TypeName.BYTE, Type.TYPE_INT32)
+          .put(TypeName.INT32, Type.TYPE_INT32)
+          .put(TypeName.INT64, Type.TYPE_INT64)
+          .put(TypeName.FLOAT, Type.TYPE_FLOAT)
+          .put(TypeName.DOUBLE, Type.TYPE_DOUBLE)
+          .put(TypeName.STRING, Type.TYPE_STRING)
+          .put(TypeName.BOOLEAN, Type.TYPE_BOOL)
+          .put(TypeName.DATETIME, Type.TYPE_INT64)
+          .put(TypeName.BYTES, Type.TYPE_BYTES)
+          .put(TypeName.DECIMAL, Type.TYPE_BYTES)
+          .build();
+
+  // A map of supported logical types to the protobuf field type.
+  static final Map<String, Type> LOGICAL_TYPES =
+      ImmutableMap.<String, Type>builder()
+          .put(SqlTypes.DATE.getIdentifier(), Type.TYPE_INT32)
+          .put(SqlTypes.TIME.getIdentifier(), Type.TYPE_INT64)
+          .put(SqlTypes.DATETIME.getIdentifier(), Type.TYPE_INT64)
+          .put(SqlTypes.TIMESTAMP.getIdentifier(), Type.TYPE_INT64)
+          .put(EnumerationType.IDENTIFIER, Type.TYPE_STRING)
+          .build();
+
+  static final Map<TypeName, Function<Object, Object>> PRIMITIVE_ENCODERS =
+      ImmutableMap.<TypeName, Function<Object, Object>>builder()
+          .put(TypeName.INT16, o -> Integer.valueOf((Short) o))
+          .put(TypeName.BYTE, o -> Integer.valueOf((Byte) o))
+          .put(TypeName.INT32, Functions.identity())
+          .put(TypeName.INT64, Functions.identity())
+          .put(TypeName.FLOAT, Function.identity())
+          .put(TypeName.DOUBLE, Function.identity())
+          .put(TypeName.STRING, Function.identity())
+          .put(TypeName.BOOLEAN, Function.identity())
+          // A Beam DATETIME is actually a timestamp, not a DateTime.
+          .put(TypeName.DATETIME, o -> ((ReadableInstant) o).getMillis() * 
1000)
+          .put(TypeName.BYTES, o -> ByteString.copyFrom((byte[]) o))
+          .put(TypeName.DECIMAL, o -> 
serializeBigDecimalToNumeric((BigDecimal) o))
+          .build();
+
+  // A map of supported logical types to their encoding functions.
+  static final Map<String, BiFunction<LogicalType<?, ?>, Object, Object>> 
LOGICAL_TYPE_ENCODERS =
+      ImmutableMap.<String, BiFunction<LogicalType<?, ?>, Object, 
Object>>builder()
+          .put(
+              SqlTypes.DATE.getIdentifier(),
+              (logicalType, value) -> (int) ((LocalDate) value).toEpochDay())
+          .put(
+              SqlTypes.TIME.getIdentifier(),
+              (logicalType, value) -> 
CivilTimeEncoder.encodePacked64TimeMicros((LocalTime) value))
+          .put(
+              SqlTypes.DATETIME.getIdentifier(),
+              (logicalType, value) ->
+                  
CivilTimeEncoder.encodePacked64DatetimeSeconds((LocalDateTime) value))
+          .put(
+              SqlTypes.TIMESTAMP.getIdentifier(),
+              (logicalType, value) -> ((java.time.Instant) 
value).toEpochMilli() * 1000)
+          .put(
+              EnumerationType.IDENTIFIER,
+              (logicalType, value) ->
+                  ((EnumerationType) 
logicalType).toString((EnumerationType.Value) value))
+          .build();
+
+  /**
+   * Given a Beam Schema, returns a protocol-buffer Descriptor that can be 
used to write data using
+   * the BigQuery Storage API.
+   */
+  public static Descriptor getDescriptorFromSchema(Schema schema)
+      throws DescriptorValidationException {
+    DescriptorProto descriptorProto = descriptorSchemaFromBeamSchema(schema);
+    FileDescriptorProto fileDescriptorProto =
+        
FileDescriptorProto.newBuilder().addMessageType(descriptorProto).build();
+    FileDescriptor fileDescriptor =
+        FileDescriptor.buildFrom(fileDescriptorProto, new FileDescriptor[0]);
+
+    return Iterables.getOnlyElement(fileDescriptor.getMessageTypes());
+  }
+
+  /**
+   * Given a Beam {@link Row} object, returns a protocol-buffer message that 
can be used to write
+   * data using the BigQuery Storage streaming API.
+   */
+  public static DynamicMessage messageFromBeamRow(Descriptor descriptor, Row 
row) {
+    Schema beamSchema = row.getSchema();
+    DynamicMessage.Builder builder = DynamicMessage.newBuilder(descriptor);
+    for (int i = 0; i < row.getFieldCount(); ++i) {
+      Field beamField = beamSchema.getField(i);
+      FieldDescriptor fieldDescriptor =
+          
Preconditions.checkNotNull(descriptor.findFieldByName(beamField.getName().toLowerCase()));
+      @Nullable Object value = messageValueFromRowValue(fieldDescriptor, 
beamField, i, row);
+      if (value != null) {
+        builder.setField(fieldDescriptor, value);
+      }
+    }
+    return builder.build();
+  }
+
+  @VisibleForTesting
+  static DescriptorProto descriptorSchemaFromBeamSchema(Schema schema) {
+    Preconditions.checkState(schema.getFieldCount() > 0);
+    DescriptorProto.Builder descriptorBuilder = DescriptorProto.newBuilder();
+    // Create a unique name for the descriptor ('-' characters cannot be used).
+    descriptorBuilder.setName("D" + UUID.randomUUID().toString().replace("-", 
"_"));
+    int i = 1;
+    List<DescriptorProto> nestedTypes = Lists.newArrayList();
+    for (Field field : schema.getFields()) {
+      FieldDescriptorProto.Builder fieldDescriptorProtoBuilder =
+          fieldDescriptorFromBeamField(field, i++, nestedTypes);
+      descriptorBuilder.addField(fieldDescriptorProtoBuilder);
+    }
+    nestedTypes.forEach(descriptorBuilder::addNestedType);
+    return descriptorBuilder.build();
+  }
+
+  private static FieldDescriptorProto.Builder fieldDescriptorFromBeamField(
+      Field field, int fieldNumber, List<DescriptorProto> nestedTypes) {
+    FieldDescriptorProto.Builder fieldDescriptorBuilder = 
FieldDescriptorProto.newBuilder();
+    fieldDescriptorBuilder = 
fieldDescriptorBuilder.setName(field.getName().toLowerCase());
+    fieldDescriptorBuilder = fieldDescriptorBuilder.setNumber(fieldNumber);
+
+    switch (field.getType().getTypeName()) {
+      case ROW:
+        @Nullable Schema rowSchema = field.getType().getRowSchema();
+        if (rowSchema == null) {
+          throw new RuntimeException("Unexpected null schema!");
+        }
+        DescriptorProto nested = descriptorSchemaFromBeamSchema(rowSchema);
+        nestedTypes.add(nested);
+        fieldDescriptorBuilder =
+            
fieldDescriptorBuilder.setType(Type.TYPE_MESSAGE).setTypeName(nested.getName());
+        break;
+      case ARRAY:
+      case ITERABLE:
+        @Nullable FieldType elementType = 
field.getType().getCollectionElementType();
+        if (elementType == null) {
+          throw new RuntimeException("Unexpected null element type!");
+        }
+        Preconditions.checkState(
+            
!Preconditions.checkNotNull(elementType.getTypeName()).isCollectionType(),
+            "Nested arrays not supported by BigQuery.");
+        return fieldDescriptorFromBeamField(
+                Field.of(field.getName(), elementType), fieldNumber, 
nestedTypes)
+            .setLabel(Label.LABEL_REPEATED);
+      case LOGICAL_TYPE:
+        @Nullable LogicalType<?, ?> logicalType = 
field.getType().getLogicalType();
+        if (logicalType == null) {
+          throw new RuntimeException("Unexpected null logical type " + 
field.getType());
+        }
+        @Nullable Type type = LOGICAL_TYPES.get(logicalType.getIdentifier());
+        if (type == null) {
+          throw new RuntimeException("Unsupported logical type " + 
field.getType());
+        }
+        fieldDescriptorBuilder = fieldDescriptorBuilder.setType(type);
+        break;
+      case MAP:
+        throw new RuntimeException("Map types not supported by BigQuery.");
+      default:
+        @Nullable Type primitiveType = 
PRIMITIVE_TYPES.get(field.getType().getTypeName());
+        if (primitiveType == null) {
+          throw new RuntimeException("Unsupported type " + field.getType());
+        }
+        fieldDescriptorBuilder = fieldDescriptorBuilder.setType(primitiveType);
+    }
+    if (field.getType().getNullable()) {
+      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_OPTIONAL);
+    } else {
+      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_REQUIRED);
+    }
+    return fieldDescriptorBuilder;
+  }
+
+  @Nullable
+  private static Object messageValueFromRowValue(
+      FieldDescriptor fieldDescriptor, Field beamField, int index, Row row) {
+    @Nullable Object value = row.getValue(index);
+    if (value == null) {
+      if (fieldDescriptor.isOptional()) {
+        return null;
+      } else {
+        throw new IllegalArgumentException(
+            "Received null value for non-nullable field " + 
fieldDescriptor.getName());
+      }
+    }
+    return toProtoValue(fieldDescriptor, beamField.getType(), value);
+  }
+
+  private static Object toProtoValue(
+      FieldDescriptor fieldDescriptor, FieldType beamFieldType, Object value) {
+    switch (beamFieldType.getTypeName()) {
+      case ROW:
+        return messageFromBeamRow(fieldDescriptor.getMessageType(), (Row) 
value);
+      case ARRAY:
+        List<Object> list = (List<Object>) value;
+        @Nullable FieldType arrayElementType = 
beamFieldType.getCollectionElementType();
+        if (arrayElementType == null) {
+          throw new RuntimeException("Unexpected null element type!");
+        }
+        return list.stream()
+            .map(v -> toProtoValue(fieldDescriptor, arrayElementType, v))
+            .collect(Collectors.toList());
+      case ITERABLE:
+        Iterable<Object> iterable = (Iterable<Object>) value;
+        @Nullable FieldType iterableElementType = 
beamFieldType.getCollectionElementType();
+        if (iterableElementType == null) {
+          throw new RuntimeException("Unexpected null element type!");
+        }
+        return StreamSupport.stream(iterable.spliterator(), false)
+            .map(v -> toProtoValue(fieldDescriptor, iterableElementType, v))
+            .collect(Collectors.toList());
+      case MAP:
+        throw new RuntimeException("Map types not supported by BigQuery.");
+      default:
+        return scalarToProtoValue(beamFieldType, value);
+    }
+  }
+
+  @VisibleForTesting
+  static Object scalarToProtoValue(FieldType beamFieldType, Object value) {
+    if (beamFieldType.getTypeName() == TypeName.LOGICAL_TYPE) {
+      @Nullable LogicalType<?, ?> logicalType = beamFieldType.getLogicalType();
+      if (logicalType == null) {
+        throw new RuntimeException("Unexpectedly null logical type " + 
beamFieldType);
+      }
+      @Nullable
+      BiFunction<LogicalType<?, ?>, Object, Object> logicalTypeEncoder =
+          LOGICAL_TYPE_ENCODERS.get(logicalType.getIdentifier());
+      if (logicalTypeEncoder == null) {
+        throw new RuntimeException("Unsupported logical type " + 
logicalType.getIdentifier());
+      }
+      return logicalTypeEncoder.apply(logicalType, value);
+    } else {
+      @Nullable
+      Function<Object, Object> encoder = 
PRIMITIVE_ENCODERS.get(beamFieldType.getTypeName());
+      if (encoder == null) {
+        throw new RuntimeException("Unexpected beam type " + beamFieldType);
+      }
+      return encoder.apply(value);
+    }
+  }
+
+  static ByteString serializeBigDecimalToNumeric(BigDecimal o) {
+    return serializeBigDecimal(o, NUMERIC_SCALE, MAX_NUMERIC_VALUE, 
MIN_NUMERIC_VALUE, "Numeric");
+  }
+
+  private static ByteString serializeBigDecimal(
+      BigDecimal v, int scale, BigDecimal maxValue, BigDecimal minValue, 
String typeName) {
+    if (v.scale() > scale) {
+      throw new IllegalArgumentException(
+          typeName + " scale cannot exceed " + scale + ": " + 
v.toPlainString());
+    }
+    if (v.compareTo(maxValue) > 0 || v.compareTo(minValue) < 0) {
+      throw new IllegalArgumentException(typeName + " overflow: " + 
v.toPlainString());
+    }
+
+    byte[] bytes = v.setScale(scale).unscaledValue().toByteArray();
+    // NUMERIC/BIGNUMERIC values are serialized as scaled integers in two's 
complement form in
+    // little endian
+    // order. BigInteger requires the same encoding but in big endian order, 
therefore we must
+    // reverse the bytes that come from the proto.
+    Bytes.reverse(bytes);
+    return ByteString.copyFrom(bytes);
+  }
+}
diff --git 
a/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtils.java
 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtils.java
index e3380ad..4ce40b6 100644
--- 
a/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtils.java
+++ 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtils.java
@@ -25,31 +25,17 @@ import 
com.google.api.services.bigquery.model.TableFieldSchema;
 import com.google.api.services.bigquery.model.TableRow;
 import com.google.api.services.bigquery.model.TableSchema;
 import com.google.auto.value.AutoValue;
-import com.google.protobuf.ByteString;
-import com.google.protobuf.DescriptorProtos.DescriptorProto;
-import com.google.protobuf.DescriptorProtos.FieldDescriptorProto;
-import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label;
-import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Type;
-import com.google.protobuf.DescriptorProtos.FileDescriptorProto;
-import com.google.protobuf.Descriptors.Descriptor;
-import com.google.protobuf.Descriptors.DescriptorValidationException;
-import com.google.protobuf.Descriptors.FieldDescriptor;
-import com.google.protobuf.Descriptors.FileDescriptor;
-import com.google.protobuf.DynamicMessage;
-import com.google.protobuf.Message;
 import java.io.Serializable;
 import java.math.BigDecimal;
 import java.nio.ByteBuffer;
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.LocalTime;
-import java.util.AbstractMap;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
-import java.util.UUID;
 import java.util.function.Function;
 import java.util.stream.IntStream;
 import org.apache.avro.Conversions;
@@ -87,22 +73,6 @@ import org.joda.time.format.DateTimeFormatterBuilder;
   "nullness" // TODO(https://issues.apache.org/jira/browse/BEAM-10402)
 })
 public class BigQueryUtils {
-
-  /**
-   * Given a BigQuery TableSchema, returns a protocol-buffer Descriptor that 
can be used to write
-   * data using the Vortex streaming API.
-   */
-  public static Descriptor getDescriptorFromTableSchema(TableSchema jsonSchema)
-      throws DescriptorValidationException {
-    DescriptorProto descriptorProto = 
descriptorSchemaFromTableSchema(jsonSchema);
-    FileDescriptorProto fileDescriptorProto =
-        
FileDescriptorProto.newBuilder().addMessageType(descriptorProto).build();
-    FileDescriptor fileDescriptor =
-        FileDescriptor.buildFrom(fileDescriptorProto, new FileDescriptor[0]);
-
-    return Iterables.getOnlyElement(fileDescriptor.getMessageTypes());
-  }
-
   /** Options for how to convert BigQuery data to Beam data. */
   @AutoValue
   public abstract static class ConversionOptions implements Serializable {
@@ -254,7 +224,7 @@ public class BigQueryUtils {
 
   // TODO: BigQuery code should not be relying on Calcite metadata fields. If 
so, this belongs
   // in the SQL package.
-  private static final Map<String, StandardSQLTypeName> 
BEAM_TO_BIGQUERY_LOGICAL_MAPPING =
+  static final Map<String, StandardSQLTypeName> 
BEAM_TO_BIGQUERY_LOGICAL_MAPPING =
       ImmutableMap.<String, StandardSQLTypeName>builder()
           .put(SqlTypes.DATE.getIdentifier(), StandardSQLTypeName.DATE)
           .put(SqlTypes.TIME.getIdentifier(), StandardSQLTypeName.TIME)
@@ -271,7 +241,7 @@ public class BigQueryUtils {
    * Get the corresponding BigQuery {@link StandardSQLTypeName} for supported 
Beam {@link
    * FieldType}.
    */
-  private static StandardSQLTypeName toStandardSQLTypeName(FieldType 
fieldType) {
+  static StandardSQLTypeName toStandardSQLTypeName(FieldType fieldType) {
     StandardSQLTypeName ret;
     if (fieldType.getTypeName().isLogicalType()) {
       ret = 
BEAM_TO_BIGQUERY_LOGICAL_MAPPING.get(fieldType.getLogicalType().getIdentifier());
@@ -434,193 +404,6 @@ public class BigQueryUtils {
     return fromTableFieldSchema(tableSchema.getFields(), options);
   }
 
-  static DescriptorProto descriptorSchemaFromTableSchema(TableSchema 
tableSchema) {
-    return descriptorSchemaFromTableFieldSchemas(tableSchema.getFields());
-  }
-
-  static DescriptorProto descriptorSchemaFromTableFieldSchemas(
-      Iterable<TableFieldSchema> tableFieldSchemas) {
-    DescriptorProto.Builder descriptorBuilder = DescriptorProto.newBuilder();
-    // Create a unique name for the descriptor ('-' characters cannot be used).
-    descriptorBuilder.setName("D" + UUID.randomUUID().toString().replace("-", 
"_"));
-    int i = 1;
-    for (TableFieldSchema fieldSchema : tableFieldSchemas) {
-      fieldDescriptorFromTableField(fieldSchema, i++, descriptorBuilder);
-    }
-    return descriptorBuilder.build();
-  }
-
-  static void fieldDescriptorFromTableField(
-      TableFieldSchema fieldSchema, int fieldNumber, DescriptorProto.Builder 
descriptorBuilder) {
-    FieldDescriptorProto.Builder fieldDescriptorBuilder = 
FieldDescriptorProto.newBuilder();
-    fieldDescriptorBuilder = 
fieldDescriptorBuilder.setName(fieldSchema.getName());
-    fieldDescriptorBuilder = fieldDescriptorBuilder.setNumber(fieldNumber);
-    switch (fieldSchema.getType()) {
-      case "STRING":
-        fieldDescriptorBuilder = 
fieldDescriptorBuilder.setType(Type.TYPE_STRING);
-        break;
-      case "BYTES":
-        fieldDescriptorBuilder = 
fieldDescriptorBuilder.setType(Type.TYPE_BYTES);
-        break;
-      case "INT64":
-      case "INTEGER":
-        fieldDescriptorBuilder = 
fieldDescriptorBuilder.setType(Type.TYPE_INT64);
-        break;
-      case "FLOAT64":
-      case "FLOAT":
-        fieldDescriptorBuilder = 
fieldDescriptorBuilder.setType(Type.TYPE_FLOAT);
-        break;
-      case "BOOL":
-      case "BOOLEAN":
-        fieldDescriptorBuilder = 
fieldDescriptorBuilder.setType(Type.TYPE_BOOL);
-        break;
-      case "TIMESTAMP":
-      case "TIME":
-      case "DATETIME":
-        fieldDescriptorBuilder = 
fieldDescriptorBuilder.setType(Type.TYPE_INT64);
-        break;
-      case "DATE":
-        fieldDescriptorBuilder = 
fieldDescriptorBuilder.setType(Type.TYPE_INT32);
-        break;
-      case "STRUCT":
-      case "RECORD":
-        DescriptorProto nested = 
descriptorSchemaFromTableFieldSchemas(fieldSchema.getFields());
-        descriptorBuilder.addNestedType(nested);
-        fieldDescriptorBuilder =
-            
fieldDescriptorBuilder.setType(Type.TYPE_MESSAGE).setTypeName(nested.getName());
-        break;
-      default:
-        throw new UnsupportedOperationException(
-            "Converting BigQuery type " + fieldSchema.getType() + " to Beam 
type is unsupported");
-    }
-
-    Optional<Mode> fieldMode = 
Optional.ofNullable(fieldSchema.getMode()).map(Mode::valueOf);
-    if (fieldMode.filter(m -> m == Mode.REPEATED).isPresent()) {
-      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_REPEATED);
-    } else if (!fieldMode.isPresent() || fieldMode.filter(m -> m == 
Mode.NULLABLE).isPresent()) {
-      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_OPTIONAL);
-    } else {
-      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_REQUIRED);
-    }
-    descriptorBuilder.addField(fieldDescriptorBuilder.build());
-  }
-
-  /**
-   * Given a BigQuery TableRow, returns a protocol-buffer message that can be 
used to write data
-   * using the Vortex streaming API.
-   */
-  public static DynamicMessage messageFromTableRow(Descriptor descriptor, 
TableRow tableRow) {
-    DynamicMessage.Builder builder = DynamicMessage.newBuilder(descriptor);
-    for (FieldDescriptor fieldDescriptor : descriptor.getFields()) {
-      Object value =
-          messageValueFromFieldValue(fieldDescriptor, 
tableRow.get(fieldDescriptor.getName()));
-      if (value != null) {
-        builder.setField(fieldDescriptor, value);
-      }
-    }
-    return builder.build();
-  }
-
-  static Object messageValueFromFieldValue(FieldDescriptor fieldDescriptor, 
Object bqValue) {
-    if (bqValue == null) {
-      if (fieldDescriptor.isOptional()) {
-        return null;
-      } else {
-        throw new IllegalArgumentException(
-            "Received null value for non-nullable field " + 
fieldDescriptor.getName());
-      }
-    }
-    return toProtoValue(fieldDescriptor, bqValue);
-  }
-
-  private static final Map<FieldDescriptor.Type, Function<String, Object>> 
JSON_PROTO_PARSERS =
-      ImmutableMap.<FieldDescriptor.Type, Function<String, Object>>builder()
-          .put(FieldDescriptor.Type.INT32, Integer::valueOf)
-          .put(FieldDescriptor.Type.INT64, Long::valueOf)
-          .put(FieldDescriptor.Type.FLOAT, Float::valueOf)
-          .put(FieldDescriptor.Type.DOUBLE, Double::valueOf)
-          .put(FieldDescriptor.Type.BOOL, Boolean::valueOf)
-          .put(FieldDescriptor.Type.STRING, str -> str)
-          .put(
-              FieldDescriptor.Type.BYTES,
-              b64 -> ByteString.copyFrom(BaseEncoding.base64().decode(b64)))
-          .build();
-
-  private static Object toProtoValue(FieldDescriptor fieldDescriptor, Object 
jsonBQValue) {
-    if (jsonBQValue instanceof String) {
-      Function<String, Object> mapper = 
JSON_PROTO_PARSERS.get(fieldDescriptor.getType());
-      if (mapper != null) {
-        return mapper.apply((String) jsonBQValue);
-      }
-    } else if (jsonBQValue instanceof Integer) {
-      switch (fieldDescriptor.getJavaType()) {
-        case INT:
-          return Integer.valueOf((int) jsonBQValue);
-        case LONG:
-          return Long.valueOf((int) jsonBQValue);
-        default:
-          throw new RuntimeException(
-              "Unexpectecd java type "
-                  + jsonBQValue.getClass()
-                  + " for field descriptor "
-                  + fieldDescriptor);
-      }
-    } else if (jsonBQValue instanceof List) {
-      return ((List<Object>) jsonBQValue)
-          .stream()
-              .map(v -> ((Map<String, Object>) v).get("v"))
-              .map(v -> toProtoValue(fieldDescriptor, v))
-              .collect(toList());
-    } else if (jsonBQValue instanceof AbstractMap) {
-      // This will handle nested rows.
-      TableRow tr = new TableRow();
-      tr.putAll((AbstractMap<String, Object>) jsonBQValue);
-      return messageFromTableRow(fieldDescriptor.getMessageType(), tr);
-    } else {
-      return toProtoValue(fieldDescriptor, jsonBQValue.toString());
-    }
-
-    throw new UnsupportedOperationException(
-        "Converting BigQuery type '"
-            + jsonBQValue.getClass()
-            + "' to '"
-            + fieldDescriptor
-            + "' is not supported");
-  }
-
-  public static TableRow tableRowFromMessage(Message message) {
-    TableRow tableRow = new TableRow();
-    for (Map.Entry<FieldDescriptor, Object> field : 
message.getAllFields().entrySet()) {
-      FieldDescriptor fieldDescriptor = field.getKey();
-      Object fieldValue = field.getValue();
-      tableRow.putIfAbsent(
-          fieldDescriptor.getName(), 
jsonValueFromMessageValue(fieldDescriptor, fieldValue, true));
-    }
-    return tableRow;
-  }
-
-  public static Object jsonValueFromMessageValue(
-      FieldDescriptor fieldDescriptor, Object fieldValue, boolean 
expandRepeated) {
-    if (expandRepeated && fieldDescriptor.isRepeated()) {
-      List<Object> valueList = (List<Object>) fieldValue;
-      return valueList.stream()
-          .map(v -> jsonValueFromMessageValue(fieldDescriptor, v, false))
-          .collect(toList());
-    }
-
-    switch (fieldDescriptor.getType()) {
-      case GROUP:
-      case MESSAGE:
-        return tableRowFromMessage((Message) fieldValue);
-      case BYTES:
-        return BaseEncoding.base64().encode(((ByteString) 
fieldValue).toByteArray());
-      case ENUM:
-        throw new RuntimeException("Enumerations not supported");
-      default:
-        return fieldValue;
-    }
-  }
-
   /** Convert a list of BigQuery {@link TableFieldSchema} to Avro {@link 
org.apache.avro.Schema}. */
   @Experimental(Kind.SCHEMAS)
   public static org.apache.avro.Schema toGenericAvroSchema(
diff --git 
a/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/CivilTimeEncoder.java
 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/CivilTimeEncoder.java
new file mode 100644
index 0000000..bed767b
--- /dev/null
+++ 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/CivilTimeEncoder.java
@@ -0,0 +1,648 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.io.gcp.bigquery;
+
+import static 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument;
+
+import java.time.temporal.ChronoUnit;
+import org.joda.time.LocalDateTime;
+import org.joda.time.LocalTime;
+
+/**
+ * Encoder for TIME and DATETIME values, according to civil_time encoding. 
Copied out of the zetasql
+ * package.
+ *
+ * <p>The valid range and number of bits required by each date/time field is 
as the following:
+ *
+ * <table>
+ *   <tr> <th> Field  </th> <th> Range          </th> <th> #Bits </th> </tr>
+ *   <tr> <td> Year   </td> <td> [1, 9999]      </td> <td> 14    </td> </tr>
+ *   <tr> <td> Month  </td> <td> [1, 12]        </td> <td> 4     </td> </tr>
+ *   <tr> <td> Day    </td> <td> [1, 31]        </td> <td> 5     </td> </tr>
+ *   <tr> <td> Hour   </td> <td> [0, 23]        </td> <td> 5     </td> </tr>
+ *   <tr> <td> Minute </td> <td> [0, 59]        </td> <td> 6     </td> </tr>
+ *   <tr> <td> Second </td> <td> [0, 59]*       </td> <td> 6     </td> </tr>
+ *   <tr> <td> Micros </td> <td> [0, 999999]    </td> <td> 20    </td> </tr>
+ *   <tr> <td> Nanos  </td> <td> [0, 999999999] </td> <td> 30    </td> </tr>
+ * </table>
+ *
+ * <p>* Leap second is not supported.
+ *
+ * <p>When encoding the TIME or DATETIME into a bit field, larger date/time 
field is on the more
+ * significant side.
+ */
+public final class CivilTimeEncoder {
+  private static final int NANO_LENGTH = 30;
+  private static final int MICRO_LENGTH = 20;
+
+  private static final int NANO_SHIFT = 0;
+  private static final int MICRO_SHIFT = 0;
+  private static final int SECOND_SHIFT = 0;
+  private static final int MINUTE_SHIFT = 6;
+  private static final int HOUR_SHIFT = 12;
+  private static final int DAY_SHIFT = 17;
+  private static final int MONTH_SHIFT = 22;
+  private static final int YEAR_SHIFT = 26;
+
+  private static final long NANO_MASK = 0x3FFFFFFFL;
+  private static final long MICRO_MASK = 0xFFFFFL;
+  private static final long SECOND_MASK = 0x3FL;
+  private static final long MINUTE_MASK = 0xFC0L;
+  private static final long HOUR_MASK = 0x1F000L;
+  private static final long DAY_MASK = 0x3E0000L;
+  private static final long MONTH_MASK = 0x3C00000L;
+  private static final long YEAR_MASK = 0xFFFC000000L;
+
+  private static final long TIME_SECONDS_MASK = 0x1FFFFL;
+  private static final long TIME_MICROS_MASK = 0x1FFFFFFFFFL;
+  private static final long TIME_NANOS_MASK = 0x7FFFFFFFFFFFL;
+  private static final long DATETIME_SECONDS_MASK = 0xFFFFFFFFFFL;
+  private static final long DATETIME_MICROS_MASK = 0xFFFFFFFFFFFFFFFL;
+
+  /**
+   * Encodes {@code time} as a 4-byte integer with seconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *      3         2         1
+   * MSB 10987654321098765432109876543210 LSB
+   *                    | H ||  M ||  S |
+   * </pre>
+   *
+   * @see #decodePacked32TimeSeconds(int)
+   * @see #encodePacked32TimeSeconds(java.time.LocalTime)
+   */
+  @SuppressWarnings("GoodTime") // should accept a java.time.LocalTime
+  public static int encodePacked32TimeSeconds(LocalTime time) {
+    checkValidTimeSeconds(time);
+    int bitFieldTimeSeconds = 0x0;
+    bitFieldTimeSeconds |= time.getHourOfDay() << HOUR_SHIFT;
+    bitFieldTimeSeconds |= time.getMinuteOfHour() << MINUTE_SHIFT;
+    bitFieldTimeSeconds |= time.getSecondOfMinute() << SECOND_SHIFT;
+    return bitFieldTimeSeconds;
+  }
+
+  /**
+   * Encodes {@code time} as a 4-byte integer with seconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *      3         2         1
+   * MSB 10987654321098765432109876543210 LSB
+   *                    | H ||  M ||  S |
+   * </pre>
+   *
+   * @see #decodePacked32TimeSecondsAsJavaTime(int)
+   */
+  @SuppressWarnings("GoodTime-ApiWithNumericTimeUnit")
+  public static int encodePacked32TimeSeconds(java.time.LocalTime time) {
+    checkValidTimeSeconds(time);
+    int bitFieldTimeSeconds = 0x0;
+    bitFieldTimeSeconds |= time.getHour() << HOUR_SHIFT;
+    bitFieldTimeSeconds |= time.getMinute() << MINUTE_SHIFT;
+    bitFieldTimeSeconds |= time.getSecond() << SECOND_SHIFT;
+    return bitFieldTimeSeconds;
+  }
+
+  /**
+   * Decodes {@code bitFieldTimeSeconds} as a {@link LocalTime} with seconds 
precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *      3         2         1
+   * MSB 10987654321098765432109876543210 LSB
+   *                    | H ||  M ||  S |
+   * </pre>
+   *
+   * @see #encodePacked32TimeSeconds(LocalTime)
+   * @see #encodePacked32TimeSecondsAsJavaTime(int)
+   */
+  @SuppressWarnings("GoodTime") // should return a java.time.LocalTime
+  public static LocalTime decodePacked32TimeSeconds(int bitFieldTimeSeconds) {
+    checkValidBitField(bitFieldTimeSeconds, TIME_SECONDS_MASK);
+    int hourOfDay = getFieldFromBitField(bitFieldTimeSeconds, HOUR_MASK, 
HOUR_SHIFT);
+    int minuteOfHour = getFieldFromBitField(bitFieldTimeSeconds, MINUTE_MASK, 
MINUTE_SHIFT);
+    int secondOfMinute = getFieldFromBitField(bitFieldTimeSeconds, 
SECOND_MASK, SECOND_SHIFT);
+    LocalTime time = new LocalTime(hourOfDay, minuteOfHour, secondOfMinute);
+    checkValidTimeSeconds(time);
+    return time;
+  }
+
+  /**
+   * Decodes {@code bitFieldTimeSeconds} as a {@link java.time.LocalTime} with 
seconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *      3         2         1
+   * MSB 10987654321098765432109876543210 LSB
+   *                    | H ||  M ||  S |
+   * </pre>
+   *
+   * @see #encodePacked32TimeSeconds(java.time.LocalTime)
+   */
+  @SuppressWarnings("GoodTime-ApiWithNumericTimeUnit")
+  public static java.time.LocalTime decodePacked32TimeSecondsAsJavaTime(int 
bitFieldTimeSeconds) {
+    checkValidBitField(bitFieldTimeSeconds, TIME_SECONDS_MASK);
+    int hourOfDay = getFieldFromBitField(bitFieldTimeSeconds, HOUR_MASK, 
HOUR_SHIFT);
+    int minuteOfHour = getFieldFromBitField(bitFieldTimeSeconds, MINUTE_MASK, 
MINUTE_SHIFT);
+    int secondOfMinute = getFieldFromBitField(bitFieldTimeSeconds, 
SECOND_MASK, SECOND_SHIFT);
+    // java.time.LocalTime validates the input parameters.
+    try {
+      return java.time.LocalTime.of(hourOfDay, minuteOfHour, secondOfMinute);
+    } catch (java.time.DateTimeException e) {
+      throw new IllegalArgumentException(e.getMessage(), e);
+    }
+  }
+
+  /**
+   * Encodes {@code time} as a 8-byte integer with microseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                                | H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * @see #decodePacked64TimeMicros(long)
+   * @see #encodePacked64TimeMicros(java.time.LocalTime)
+   */
+  @SuppressWarnings("GoodTime") // should accept a java.time.LocalTime
+  public static long encodePacked64TimeMicros(LocalTime time) {
+    checkValidTimeMillis(time);
+    return (((long) encodePacked32TimeSeconds(time)) << MICRO_LENGTH)
+        | (time.getMillisOfSecond() * 1_000L);
+  }
+
+  /**
+   * Encodes {@code time} as a 8-byte integer with microseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                                | H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * @see #decodePacked64TimeMicrosAsJavaTime(long)
+   */
+  @SuppressWarnings({"GoodTime-ApiWithNumericTimeUnit", 
"JavaLocalTimeGetNano"})
+  public static long encodePacked64TimeMicros(java.time.LocalTime time) {
+    checkValidTimeMicros(time);
+    return (((long) encodePacked32TimeSeconds(time)) << MICRO_LENGTH) | 
(time.getNano() / 1_000L);
+  }
+
+  /**
+   * Decodes {@code bitFieldTimeMicros} as a {@link LocalTime} with 
microseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                                | H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * <p><b>Warning: LocalTime only supports milliseconds precision. Result is 
truncated.</b>
+   *
+   * @see #encodePacked64TimeMicros(LocalTime)
+   * @see #decodePacked64TimeMicrosAsJavaTime(long)
+   */
+  @SuppressWarnings("GoodTime") // should return a java.time.LocalTime
+  public static LocalTime decodePacked64TimeMicros(long bitFieldTimeMicros) {
+    checkValidBitField(bitFieldTimeMicros, TIME_MICROS_MASK);
+    int bitFieldTimeSeconds = (int) (bitFieldTimeMicros >> MICRO_LENGTH);
+    LocalTime timeSeconds = decodePacked32TimeSeconds(bitFieldTimeSeconds);
+    int microOfSecond = getFieldFromBitField(bitFieldTimeMicros, MICRO_MASK, 
MICRO_SHIFT);
+    checkValidMicroOfSecond(microOfSecond);
+    LocalTime time = timeSeconds.withMillisOfSecond(microOfSecond / 1_000);
+    checkValidTimeMillis(time);
+    return time;
+  }
+
+  /**
+   * Decodes {@code bitFieldTimeMicros} as a {@link java.time.LocalTime} with 
microseconds
+   * precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                                | H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * @see #encodePacked64TimeMicros(java.time.LocalTime)
+   */
+  @SuppressWarnings("GoodTime-ApiWithNumericTimeUnit")
+  public static java.time.LocalTime decodePacked64TimeMicrosAsJavaTime(long 
bitFieldTimeMicros) {
+    checkValidBitField(bitFieldTimeMicros, TIME_MICROS_MASK);
+    int bitFieldTimeSeconds = (int) (bitFieldTimeMicros >> MICRO_LENGTH);
+    java.time.LocalTime timeSeconds = 
decodePacked32TimeSecondsAsJavaTime(bitFieldTimeSeconds);
+    int microOfSecond = getFieldFromBitField(bitFieldTimeMicros, MICRO_MASK, 
MICRO_SHIFT);
+    checkValidMicroOfSecond(microOfSecond);
+    return timeSeconds.withNano(microOfSecond * 1_000);
+  }
+
+  /**
+   * Encodes {@code time} as a 8-byte integer with nanoseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                      | H ||  M ||  S ||---------- nanos -----------|
+   * </pre>
+   *
+   * @see #decodePacked64TimeNanos(long)
+   * @see #encodePacked64TimeNanos(java.time.LocalTime)
+   */
+  @SuppressWarnings("GoodTime") // should accept a java.time.LocalTime
+  public static long encodePacked64TimeNanos(LocalTime time) {
+    checkValidTimeMillis(time);
+    return (((long) encodePacked32TimeSeconds(time)) << NANO_LENGTH)
+        | (time.getMillisOfSecond() * 1_000_000L);
+  }
+
+  /**
+   * Encodes {@code time} as a 8-byte integer with nanoseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                      | H ||  M ||  S ||---------- nanos -----------|
+   * </pre>
+   *
+   * @see #decodePacked64TimeNanosAsJavaTime(long)
+   */
+  @SuppressWarnings({"GoodTime-ApiWithNumericTimeUnit", 
"JavaLocalTimeGetNano"})
+  public static long encodePacked64TimeNanos(java.time.LocalTime time) {
+    checkValidTimeNanos(time);
+    return (((long) encodePacked32TimeSeconds(time)) << NANO_LENGTH) | 
time.getNano();
+  }
+
+  /**
+   * Decodes {@code bitFieldTimeNanos} as a {@link LocalTime} with nanoseconds 
precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                      | H ||  M ||  S ||---------- nanos -----------|
+   * </pre>
+   *
+   * <p><b>Warning: LocalTime only supports milliseconds precision. Result is 
truncated.</b>
+   *
+   * @see #encodePacked64TimeNanos(LocalTime)
+   * @see #decodePacked64TimeNanosAsJavaTime(long)
+   */
+  @SuppressWarnings("GoodTime") // should return a java.time.LocalTime
+  public static LocalTime decodePacked64TimeNanos(long bitFieldTimeNanos) {
+    checkValidBitField(bitFieldTimeNanos, TIME_NANOS_MASK);
+    int bitFieldTimeSeconds = (int) (bitFieldTimeNanos >> NANO_LENGTH);
+    LocalTime timeSeconds = decodePacked32TimeSeconds(bitFieldTimeSeconds);
+    int nanoOfSecond = getFieldFromBitField(bitFieldTimeNanos, NANO_MASK, 
NANO_SHIFT);
+    checkValidNanoOfSecond(nanoOfSecond);
+    LocalTime time = timeSeconds.withMillisOfSecond(nanoOfSecond / 1_000_000);
+    checkValidTimeMillis(time);
+    return time;
+  }
+
+  /**
+   * Decodes {@code bitFieldTimeNanos} as a {@link java.time.LocalTime} with 
nanoseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                      | H ||  M ||  S ||---------- nanos -----------|
+   * </pre>
+   *
+   * @see #encodePacked64TimeNanos(java.time.LocalTime)
+   */
+  @SuppressWarnings("GoodTime-ApiWithNumericTimeUnit")
+  public static java.time.LocalTime decodePacked64TimeNanosAsJavaTime(long 
bitFieldTimeNanos) {
+    checkValidBitField(bitFieldTimeNanos, TIME_NANOS_MASK);
+    int bitFieldTimeSeconds = (int) (bitFieldTimeNanos >> NANO_LENGTH);
+    java.time.LocalTime timeSeconds = 
decodePacked32TimeSecondsAsJavaTime(bitFieldTimeSeconds);
+    int nanoOfSecond = getFieldFromBitField(bitFieldTimeNanos, NANO_MASK, 
NANO_SHIFT);
+    checkValidNanoOfSecond(nanoOfSecond);
+    return timeSeconds.withNano(nanoOfSecond);
+  }
+
+  /**
+   * Encodes {@code dateTime} as a 8-byte integer with seconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                             |--- year ---||m || D || H ||  M ||  S |
+   * </pre>
+   *
+   * @see #decodePacked64DatetimeSeconds(long)
+   * @see #encodePacked64DatetimeSeconds(java.time.LocalDateTime)
+   */
+  @SuppressWarnings("GoodTime") // should accept a java.time.LocalDateTime
+  public static long encodePacked64DatetimeSeconds(LocalDateTime dateTime) {
+    checkValidDateTimeSeconds(dateTime);
+    long bitFieldDatetimeSeconds = 0x0L;
+    bitFieldDatetimeSeconds |= (long) dateTime.getYear() << YEAR_SHIFT;
+    bitFieldDatetimeSeconds |= (long) dateTime.getMonthOfYear() << MONTH_SHIFT;
+    bitFieldDatetimeSeconds |= (long) dateTime.getDayOfMonth() << DAY_SHIFT;
+    bitFieldDatetimeSeconds |= (long) 
encodePacked32TimeSeconds(dateTime.toLocalTime());
+    return bitFieldDatetimeSeconds;
+  }
+
+  /**
+   * Encodes {@code dateTime} as a 8-byte integer with seconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                             |--- year ---||m || D || H ||  M ||  S |
+   * </pre>
+   *
+   * @see #decodePacked64DatetimeSecondsAsJavaTime(long)
+   */
+  @SuppressWarnings("GoodTime-ApiWithNumericTimeUnit")
+  public static long encodePacked64DatetimeSeconds(java.time.LocalDateTime 
dateTime) {
+    checkValidDateTimeSeconds(dateTime);
+    long bitFieldDatetimeSeconds = 0x0L;
+    bitFieldDatetimeSeconds |= (long) dateTime.getYear() << YEAR_SHIFT;
+    bitFieldDatetimeSeconds |= (long) dateTime.getMonthValue() << MONTH_SHIFT;
+    bitFieldDatetimeSeconds |= (long) dateTime.getDayOfMonth() << DAY_SHIFT;
+    bitFieldDatetimeSeconds |= (long) 
encodePacked32TimeSeconds(dateTime.toLocalTime());
+    return bitFieldDatetimeSeconds;
+  }
+
+  /**
+   * Decodes {@code bitFieldDatetimeSeconds} as a {@link LocalDateTime} with 
seconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                             |--- year ---||m || D || H ||  M ||  S |
+   * </pre>
+   *
+   * @see #encodePacked64DatetimeSeconds(LocalDateTime)
+   * @see #decodePacked64DatetimeSecondsAsJavaTime(long)
+   */
+  @SuppressWarnings("GoodTime") // should return a java.time.LocalDateTime
+  public static LocalDateTime decodePacked64DatetimeSeconds(long 
bitFieldDatetimeSeconds) {
+    checkValidBitField(bitFieldDatetimeSeconds, DATETIME_SECONDS_MASK);
+    int bitFieldTimeSeconds = (int) (bitFieldDatetimeSeconds & 
TIME_SECONDS_MASK);
+    LocalTime timeSeconds = decodePacked32TimeSeconds(bitFieldTimeSeconds);
+    int year = getFieldFromBitField(bitFieldDatetimeSeconds, YEAR_MASK, 
YEAR_SHIFT);
+    int monthOfYear = getFieldFromBitField(bitFieldDatetimeSeconds, 
MONTH_MASK, MONTH_SHIFT);
+    int dayOfMonth = getFieldFromBitField(bitFieldDatetimeSeconds, DAY_MASK, 
DAY_SHIFT);
+    LocalDateTime dateTime =
+        new LocalDateTime(
+            year,
+            monthOfYear,
+            dayOfMonth,
+            timeSeconds.getHourOfDay(),
+            timeSeconds.getMinuteOfHour(),
+            timeSeconds.getSecondOfMinute());
+    checkValidDateTimeSeconds(dateTime);
+    return dateTime;
+  }
+
+  /**
+   * Decodes {@code bitFieldDatetimeSeconds} as a {@link LocalDateTime} with 
seconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *                             |--- year ---||m || D || H ||  M ||  S |
+   * </pre>
+   *
+   * @see #encodePacked64DatetimeSeconds(java.time.LocalDateTime)
+   */
+  @SuppressWarnings("GoodTime-ApiWithNumericTimeUnit")
+  public static java.time.LocalDateTime 
decodePacked64DatetimeSecondsAsJavaTime(
+      long bitFieldDatetimeSeconds) {
+    checkValidBitField(bitFieldDatetimeSeconds, DATETIME_SECONDS_MASK);
+    int bitFieldTimeSeconds = (int) (bitFieldDatetimeSeconds & 
TIME_SECONDS_MASK);
+    java.time.LocalTime timeSeconds = 
decodePacked32TimeSecondsAsJavaTime(bitFieldTimeSeconds);
+    int year = getFieldFromBitField(bitFieldDatetimeSeconds, YEAR_MASK, 
YEAR_SHIFT);
+    int monthOfYear = getFieldFromBitField(bitFieldDatetimeSeconds, 
MONTH_MASK, MONTH_SHIFT);
+    int dayOfMonth = getFieldFromBitField(bitFieldDatetimeSeconds, DAY_MASK, 
DAY_SHIFT);
+    try {
+      java.time.LocalDateTime dateTime =
+          java.time.LocalDateTime.of(
+              year,
+              monthOfYear,
+              dayOfMonth,
+              timeSeconds.getHour(),
+              timeSeconds.getMinute(),
+              timeSeconds.getSecond());
+      checkValidDateTimeSeconds(dateTime);
+      return dateTime;
+    } catch (java.time.DateTimeException e) {
+      throw new IllegalArgumentException(e.getMessage(), e);
+    }
+  }
+
+  /**
+   * Encodes {@code dateTime} as a 8-byte integer with microseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *         |--- year ---||m || D || H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * @see #decodePacked64DatetimeMicros(long)
+   * @see #encodePacked64DatetimeMicros(java.time.LocalDateTime)
+   */
+  @SuppressWarnings("GoodTime") // should accept a java.time.LocalDateTime
+  public static long encodePacked64DatetimeMicros(LocalDateTime dateTime) {
+    checkValidDateTimeMillis(dateTime);
+    return (encodePacked64DatetimeSeconds(dateTime) << MICRO_LENGTH)
+        | (dateTime.getMillisOfSecond() * 1_000L);
+  }
+
+  /**
+   * Encodes {@code dateTime} as a 8-byte integer with microseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *         |--- year ---||m || D || H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * @see #decodePacked64DatetimeMicrosAsJavaTime(long)
+   */
+  @SuppressWarnings({"GoodTime-ApiWithNumericTimeUnit", 
"JavaLocalDateTimeGetNano"})
+  public static long encodePacked64DatetimeMicros(java.time.LocalDateTime 
dateTime) {
+    checkValidDateTimeMicros(dateTime);
+    return (encodePacked64DatetimeSeconds(dateTime) << MICRO_LENGTH)
+        | (dateTime.getNano() / 1_000L);
+  }
+
+  /**
+   * Decodes {@code bitFieldDatetimeMicros} as a {@link LocalDateTime} with 
microseconds precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *         |--- year ---||m || D || H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * <p><b>Warning: LocalDateTime only supports milliseconds precision. Result 
is truncated.</b>
+   *
+   * @see #encodePacked64DatetimeMicros(LocalDateTime)
+   * @see #decodePacked64DatetimeMicrosAsJavaTime(long)
+   */
+  @SuppressWarnings("GoodTime") // should return a java.time.LocalDateTime
+  public static LocalDateTime decodePacked64DatetimeMicros(long 
bitFieldDatetimeMicros) {
+    checkValidBitField(bitFieldDatetimeMicros, DATETIME_MICROS_MASK);
+    long bitFieldDatetimeSeconds = bitFieldDatetimeMicros >> MICRO_LENGTH;
+    LocalDateTime dateTimeSeconds = 
decodePacked64DatetimeSeconds(bitFieldDatetimeSeconds);
+    int microOfSecond = getFieldFromBitField(bitFieldDatetimeMicros, 
MICRO_MASK, MICRO_SHIFT);
+    checkValidMicroOfSecond(microOfSecond);
+    LocalDateTime dateTime = dateTimeSeconds.withMillisOfSecond(microOfSecond 
/ 1_000);
+    checkValidDateTimeMillis(dateTime);
+    return dateTime;
+  }
+
+  /**
+   * Decodes {@code bitFieldDatetimeMicros} as a {@link 
java.time.LocalDateTime} with microseconds
+   * precision.
+   *
+   * <p>Encoding is as the following:
+   *
+   * <pre>
+   *        6         5         4         3         2         1
+   * MSB 3210987654321098765432109876543210987654321098765432109876543210 LSB
+   *         |--- year ---||m || D || H ||  M ||  S ||-------micros-----|
+   * </pre>
+   *
+   * @see #encodePacked64DatetimeMicros(java.time.LocalDateTime)
+   */
+  @SuppressWarnings("GoodTime-ApiWithNumericTimeUnit")
+  public static java.time.LocalDateTime decodePacked64DatetimeMicrosAsJavaTime(
+      long bitFieldDatetimeMicros) {
+    checkValidBitField(bitFieldDatetimeMicros, DATETIME_MICROS_MASK);
+    long bitFieldDatetimeSeconds = bitFieldDatetimeMicros >> MICRO_LENGTH;
+    java.time.LocalDateTime dateTimeSeconds =
+        decodePacked64DatetimeSecondsAsJavaTime(bitFieldDatetimeSeconds);
+    int microOfSecond = getFieldFromBitField(bitFieldDatetimeMicros, 
MICRO_MASK, MICRO_SHIFT);
+    checkValidMicroOfSecond(microOfSecond);
+    java.time.LocalDateTime dateTime = dateTimeSeconds.withNano(microOfSecond 
* 1_000);
+    checkValidDateTimeMicros(dateTime);
+    return dateTime;
+  }
+
+  private static int getFieldFromBitField(long bitField, long mask, int shift) 
{
+    return (int) ((bitField & mask) >> shift);
+  }
+
+  private static void checkValidTimeSeconds(LocalTime time) {
+    checkArgument(time.getHourOfDay() >= 0 && time.getHourOfDay() <= 23);
+    checkArgument(time.getMinuteOfHour() >= 0 && time.getMinuteOfHour() <= 59);
+    checkArgument(time.getSecondOfMinute() >= 0 && time.getSecondOfMinute() <= 
59);
+  }
+
+  private static void checkValidTimeSeconds(java.time.LocalTime time) {
+    checkArgument(time.getHour() >= 0 && time.getHour() <= 23);
+    checkArgument(time.getMinute() >= 0 && time.getMinute() <= 59);
+    checkArgument(time.getSecond() >= 0 && time.getSecond() <= 59);
+  }
+
+  private static void checkValidTimeMillis(LocalTime time) {
+    checkValidTimeSeconds(time);
+    checkArgument(time.getMillisOfSecond() >= 0 && time.getMillisOfSecond() <= 
999);
+  }
+
+  private static void checkValidTimeMicros(java.time.LocalTime time) {
+    checkValidTimeSeconds(time);
+    checkArgument(time.equals(time.truncatedTo(ChronoUnit.MICROS)));
+  }
+
+  private static void checkValidTimeNanos(java.time.LocalTime time) {
+    checkValidTimeSeconds(time);
+  }
+
+  private static void checkValidDateTimeSeconds(LocalDateTime dateTime) {
+    checkArgument(dateTime.getYear() >= 1 && dateTime.getYear() <= 9999);
+    checkArgument(dateTime.getMonthOfYear() >= 1 && dateTime.getMonthOfYear() 
<= 12);
+    checkArgument(dateTime.getDayOfMonth() >= 1 && dateTime.getDayOfMonth() <= 
31);
+    checkValidTimeSeconds(dateTime.toLocalTime());
+  }
+
+  private static void checkValidDateTimeSeconds(java.time.LocalDateTime 
dateTime) {
+    checkArgument(dateTime.getYear() >= 1 && dateTime.getYear() <= 9999);
+    checkArgument(dateTime.getMonthValue() >= 1 && dateTime.getMonthValue() <= 
12);
+    checkArgument(dateTime.getDayOfMonth() >= 1 && dateTime.getDayOfMonth() <= 
31);
+    checkValidTimeSeconds(dateTime.toLocalTime());
+  }
+
+  private static void checkValidDateTimeMillis(LocalDateTime dateTime) {
+    checkValidDateTimeSeconds(dateTime);
+    checkArgument(dateTime.getMillisOfSecond() >= 0 && 
dateTime.getMillisOfSecond() <= 999);
+  }
+
+  private static void checkValidDateTimeMicros(java.time.LocalDateTime 
dateTime) {
+    checkValidDateTimeSeconds(dateTime);
+    checkArgument(dateTime.equals(dateTime.truncatedTo(ChronoUnit.MICROS)));
+  }
+
+  private static void checkValidDateTimeNanos(java.time.LocalDateTime 
dateTime) {
+    checkValidDateTimeSeconds(dateTime);
+  }
+
+  private static void checkValidMicroOfSecond(int microOfSecond) {
+    checkArgument(microOfSecond >= 0 && microOfSecond <= 999999);
+  }
+
+  private static void checkValidNanoOfSecond(int nanoOfSecond) {
+    checkArgument(nanoOfSecond >= 0 && nanoOfSecond <= 999999999);
+  }
+
+  private static void checkValidBitField(long bitField, long mask) {
+    checkArgument((bitField & ~mask) == 0x0L);
+  }
+
+  private CivilTimeEncoder() {}
+}
diff --git 
a/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/TableRowToStorageApiProto.java
 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/TableRowToStorageApiProto.java
new file mode 100644
index 0000000..873832f
--- /dev/null
+++ 
b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/TableRowToStorageApiProto.java
@@ -0,0 +1,304 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.io.gcp.bigquery;
+
+import static java.util.stream.Collectors.toList;
+
+import com.google.api.services.bigquery.model.TableFieldSchema;
+import com.google.api.services.bigquery.model.TableRow;
+import com.google.api.services.bigquery.model.TableSchema;
+import com.google.protobuf.ByteString;
+import com.google.protobuf.DescriptorProtos.DescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Type;
+import com.google.protobuf.DescriptorProtos.FileDescriptorProto;
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.DescriptorValidationException;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.FileDescriptor;
+import com.google.protobuf.DynamicMessage;
+import com.google.protobuf.Message;
+import java.util.AbstractMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.function.Function;
+import javax.annotation.Nullable;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.annotations.VisibleForTesting;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableMap;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Iterables;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.io.BaseEncoding;
+
+/**
+ * Utility methods for converting JSON {@link TableRow} objects to dynamic 
protocol message, for use
+ * with the Storage write API.
+ */
+public class TableRowToStorageApiProto {
+  static final Map<String, Type> PRIMITIVE_TYPES =
+      ImmutableMap.<String, Type>builder()
+          .put("INT64", Type.TYPE_INT64)
+          .put("INTEGER", Type.TYPE_INT64)
+          .put("FLOAT64", Type.TYPE_DOUBLE)
+          .put("FLOAT", Type.TYPE_DOUBLE)
+          .put("STRING", Type.TYPE_STRING)
+          .put("BOOL", Type.TYPE_BOOL)
+          .put("BOOLEAN", Type.TYPE_BOOL)
+          .put("BYTES", Type.TYPE_BYTES)
+          .put("NUMERIC", Type.TYPE_STRING) // Pass through the JSON encoding.
+          .put("BIGNUMERIC", Type.TYPE_STRING) // Pass through the JSON 
encoding.
+          .put("GEOGRAPHY", Type.TYPE_STRING) // Pass through the JSON 
encoding.
+          .put("DATE", Type.TYPE_STRING) // Pass through the JSON encoding.
+          .put("TIME", Type.TYPE_STRING) // Pass through the JSON encoding.
+          .put("DATETIME", Type.TYPE_STRING) // Pass through the JSON encoding.
+          .put("TIMESTAMP", Type.TYPE_STRING) // Pass through the JSON 
encoding.
+          .build();
+
+  /**
+   * Given a BigQuery TableSchema, returns a protocol-buffer Descriptor that 
can be used to write
+   * data using the BigQuery Storage API.
+   */
+  public static Descriptor getDescriptorFromTableSchema(TableSchema jsonSchema)
+      throws DescriptorValidationException {
+    DescriptorProto descriptorProto = 
descriptorSchemaFromTableSchema(jsonSchema);
+    FileDescriptorProto fileDescriptorProto =
+        
FileDescriptorProto.newBuilder().addMessageType(descriptorProto).build();
+    FileDescriptor fileDescriptor =
+        FileDescriptor.buildFrom(fileDescriptorProto, new FileDescriptor[0]);
+
+    return Iterables.getOnlyElement(fileDescriptor.getMessageTypes());
+  }
+
+  /**
+   * Given a BigQuery TableRow, returns a protocol-buffer message that can be 
used to write data
+   * using the BigQuery Storage API.
+   */
+  public static DynamicMessage messageFromTableRow(Descriptor descriptor, 
TableRow tableRow) {
+    DynamicMessage.Builder builder = DynamicMessage.newBuilder(descriptor);
+    for (Map.Entry<String, Object> entry : tableRow.entrySet()) {
+      FieldDescriptor fieldDescriptor = 
descriptor.findFieldByName(entry.getKey().toLowerCase());
+      Object value = messageValueFromFieldValue(fieldDescriptor, 
entry.getValue());
+      if (value != null) {
+        builder.setField(fieldDescriptor, value);
+      }
+    }
+    return builder.build();
+  }
+
+  @VisibleForTesting
+  static DescriptorProto descriptorSchemaFromTableSchema(TableSchema 
tableSchema) {
+    return descriptorSchemaFromTableFieldSchemas(tableSchema.getFields());
+  }
+
+  private static DescriptorProto descriptorSchemaFromTableFieldSchemas(
+      Iterable<TableFieldSchema> tableFieldSchemas) {
+    DescriptorProto.Builder descriptorBuilder = DescriptorProto.newBuilder();
+    // Create a unique name for the descriptor ('-' characters cannot be used).
+    descriptorBuilder.setName("D" + UUID.randomUUID().toString().replace("-", 
"_"));
+    int i = 1;
+    for (TableFieldSchema fieldSchema : tableFieldSchemas) {
+      fieldDescriptorFromTableField(fieldSchema, i++, descriptorBuilder);
+    }
+    return descriptorBuilder.build();
+  }
+
+  private static void fieldDescriptorFromTableField(
+      TableFieldSchema fieldSchema, int fieldNumber, DescriptorProto.Builder 
descriptorBuilder) {
+    FieldDescriptorProto.Builder fieldDescriptorBuilder = 
FieldDescriptorProto.newBuilder();
+    fieldDescriptorBuilder = 
fieldDescriptorBuilder.setName(fieldSchema.getName().toLowerCase());
+    fieldDescriptorBuilder = fieldDescriptorBuilder.setNumber(fieldNumber);
+    switch (fieldSchema.getType()) {
+      case "STRUCT":
+      case "RECORD":
+        DescriptorProto nested = 
descriptorSchemaFromTableFieldSchemas(fieldSchema.getFields());
+        descriptorBuilder.addNestedType(nested);
+        fieldDescriptorBuilder =
+            
fieldDescriptorBuilder.setType(Type.TYPE_MESSAGE).setTypeName(nested.getName());
+        break;
+      default:
+        @Nullable Type type = PRIMITIVE_TYPES.get(fieldSchema.getType());
+        if (type == null) {
+          throw new UnsupportedOperationException(
+              "Converting BigQuery type " + fieldSchema.getType() + " to Beam 
type is unsupported");
+        }
+        fieldDescriptorBuilder = fieldDescriptorBuilder.setType(type);
+    }
+
+    Optional<Mode> fieldMode = 
Optional.ofNullable(fieldSchema.getMode()).map(Mode::valueOf);
+    if (fieldMode.filter(m -> m == Mode.REPEATED).isPresent()) {
+      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_REPEATED);
+    } else if (!fieldMode.isPresent() || fieldMode.filter(m -> m == 
Mode.NULLABLE).isPresent()) {
+      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_OPTIONAL);
+    } else {
+      fieldDescriptorBuilder = 
fieldDescriptorBuilder.setLabel(Label.LABEL_REQUIRED);
+    }
+    descriptorBuilder.addField(fieldDescriptorBuilder.build());
+  }
+
+  @Nullable
+  private static Object messageValueFromFieldValue(
+      FieldDescriptor fieldDescriptor, Object bqValue) {
+    if (bqValue == null) {
+      if (fieldDescriptor.isOptional()) {
+        return null;
+      } else {
+        throw new IllegalArgumentException(
+            "Received null value for non-nullable field " + 
fieldDescriptor.getName());
+      }
+    }
+    return toProtoValue(fieldDescriptor, bqValue, 
fieldDescriptor.isRepeated());
+  }
+
+  private static final Map<FieldDescriptor.Type, Function<String, Object>>
+      JSON_PROTO_STRING_PARSERS =
+          ImmutableMap.<FieldDescriptor.Type, Function<String, 
Object>>builder()
+              .put(FieldDescriptor.Type.INT32, Integer::valueOf)
+              .put(FieldDescriptor.Type.INT64, Long::valueOf)
+              .put(FieldDescriptor.Type.FLOAT, Float::valueOf)
+              .put(FieldDescriptor.Type.DOUBLE, Double::valueOf)
+              .put(FieldDescriptor.Type.BOOL, Boolean::valueOf)
+              .put(FieldDescriptor.Type.STRING, str -> str)
+              .put(
+                  FieldDescriptor.Type.BYTES,
+                  b64 -> 
ByteString.copyFrom(BaseEncoding.base64().decode(b64)))
+              .build();
+
+  @Nullable
+  @SuppressWarnings({"nullness"})
+  @VisibleForTesting
+  static Object toProtoValue(
+      FieldDescriptor fieldDescriptor, Object jsonBQValue, boolean isRepeated) 
{
+    if (isRepeated) {
+      return ((List<Object>) jsonBQValue)
+          .stream()
+              .map(
+                  v -> {
+                    if (fieldDescriptor.getType() == 
FieldDescriptor.Type.MESSAGE) {
+                      return ((Map<String, Object>) v).get("v");
+                    } else {
+                      return v;
+                    }
+                  })
+              .map(v -> toProtoValue(fieldDescriptor, v, false))
+              .collect(toList());
+    }
+
+    if (fieldDescriptor.getType() == FieldDescriptor.Type.MESSAGE) {
+      if (jsonBQValue instanceof AbstractMap) {
+        // This will handle nested rows.
+        TableRow tr = new TableRow();
+        tr.putAll((AbstractMap<String, Object>) jsonBQValue);
+        return messageFromTableRow(fieldDescriptor.getMessageType(), tr);
+      } else {
+        throw new RuntimeException("Unexpected value " + jsonBQValue + " 
Expected a JSON map.");
+      }
+    }
+    @Nullable Object scalarValue = scalarToProtoValue(fieldDescriptor, 
jsonBQValue);
+    if (scalarValue == null) {
+      return toProtoValue(fieldDescriptor, jsonBQValue.toString(), isRepeated);
+    } else {
+      return scalarValue;
+    }
+  }
+
+  @VisibleForTesting
+  @Nullable
+  static Object scalarToProtoValue(FieldDescriptor fieldDescriptor, Object 
jsonBQValue) {
+    if (jsonBQValue instanceof String) {
+      Function<String, Object> mapper = 
JSON_PROTO_STRING_PARSERS.get(fieldDescriptor.getType());
+      if (mapper == null) {
+        throw new UnsupportedOperationException(
+            "Converting BigQuery type '"
+                + jsonBQValue.getClass()
+                + "' to '"
+                + fieldDescriptor
+                + "' is not supported");
+      }
+      return mapper.apply((String) jsonBQValue);
+    }
+
+    switch (fieldDescriptor.getType()) {
+      case BOOL:
+        if (jsonBQValue instanceof Boolean) {
+          return jsonBQValue;
+        }
+        break;
+      case BYTES:
+        break;
+      case INT64:
+        if (jsonBQValue instanceof Integer) {
+          return Long.valueOf((Integer) jsonBQValue);
+        } else if (jsonBQValue instanceof Long) {
+          return jsonBQValue;
+        }
+        break;
+      case INT32:
+        if (jsonBQValue instanceof Integer) {
+          return jsonBQValue;
+        }
+        break;
+      case STRING:
+        break;
+      case DOUBLE:
+        if (jsonBQValue instanceof Double) {
+          return jsonBQValue;
+        } else if (jsonBQValue instanceof Float) {
+          return Double.valueOf((Float) jsonBQValue);
+        }
+        break;
+      default:
+        throw new RuntimeException("Unsupported proto type " + 
fieldDescriptor.getType());
+    }
+    return null;
+  }
+
+  @VisibleForTesting
+  public static TableRow tableRowFromMessage(Message message) {
+    TableRow tableRow = new TableRow();
+    for (Map.Entry<FieldDescriptor, Object> field : 
message.getAllFields().entrySet()) {
+      FieldDescriptor fieldDescriptor = field.getKey();
+      Object fieldValue = field.getValue();
+      tableRow.putIfAbsent(
+          fieldDescriptor.getName(), 
jsonValueFromMessageValue(fieldDescriptor, fieldValue, true));
+    }
+    return tableRow;
+  }
+
+  public static Object jsonValueFromMessageValue(
+      FieldDescriptor fieldDescriptor, Object fieldValue, boolean 
expandRepeated) {
+    if (expandRepeated && fieldDescriptor.isRepeated()) {
+      List<Object> valueList = (List<Object>) fieldValue;
+      return valueList.stream()
+          .map(v -> jsonValueFromMessageValue(fieldDescriptor, v, false))
+          .collect(toList());
+    }
+
+    switch (fieldDescriptor.getType()) {
+      case GROUP:
+      case MESSAGE:
+        return tableRowFromMessage((Message) fieldValue);
+      case BYTES:
+        return BaseEncoding.base64().encode(((ByteString) 
fieldValue).toByteArray());
+      case ENUM:
+        throw new RuntimeException("Enumerations not supported");
+      default:
+        return fieldValue;
+    }
+  }
+}
diff --git 
a/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/BeamRowToStorageApiProtoTest.java
 
b/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/BeamRowToStorageApiProtoTest.java
new file mode 100644
index 0000000..32c0b7a
--- /dev/null
+++ 
b/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/BeamRowToStorageApiProtoTest.java
@@ -0,0 +1,391 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.io.gcp.bigquery;
+
+import static org.junit.Assert.assertEquals;
+
+import com.google.protobuf.ByteString;
+import com.google.protobuf.DescriptorProtos.DescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Type;
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.DynamicMessage;
+import java.math.BigDecimal;
+import java.nio.charset.StandardCharsets;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.util.Map;
+import java.util.stream.Collectors;
+import org.apache.beam.sdk.schemas.Schema;
+import org.apache.beam.sdk.schemas.Schema.Field;
+import org.apache.beam.sdk.schemas.Schema.FieldType;
+import org.apache.beam.sdk.schemas.logicaltypes.EnumerationType;
+import org.apache.beam.sdk.schemas.logicaltypes.SqlTypes;
+import org.apache.beam.sdk.values.Row;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Functions;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableList;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableMap;
+import org.joda.time.Instant;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+@SuppressWarnings({
+  "nullness" // TODO(https://issues.apache.org/jira/browse/BEAM-10402)
+})
+/** Unit tests form {@link BeamRowToStorageApiProto}. */
+public class BeamRowToStorageApiProtoTest {
+  private static final EnumerationType TEST_ENUM =
+      EnumerationType.create("ONE", "TWO", "RED", "BLUE");
+  private static final Schema BASE_SCHEMA =
+      Schema.builder()
+          .addField("byteValue", FieldType.BYTE.withNullable(true))
+          .addField("int16Value", FieldType.INT16)
+          .addField("int32Value", FieldType.INT32.withNullable(true))
+          .addField("int64Value", FieldType.INT64.withNullable(true))
+          .addField("decimalValue", FieldType.DECIMAL.withNullable(true))
+          .addField("floatValue", FieldType.FLOAT.withNullable(true))
+          .addField("doubleValue", FieldType.DOUBLE.withNullable(true))
+          .addField("stringValue", FieldType.STRING.withNullable(true))
+          .addField("datetimeValue", FieldType.DATETIME.withNullable(true))
+          .addField("booleanValue", FieldType.BOOLEAN.withNullable(true))
+          .addField("bytesValue", FieldType.BYTES.withNullable(true))
+          .addField("arrayValue", FieldType.array(FieldType.STRING))
+          .addField("iterableValue", FieldType.array(FieldType.STRING))
+          .addField("sqlDateValue", 
FieldType.logicalType(SqlTypes.DATE).withNullable(true))
+          .addField("sqlTimeValue", 
FieldType.logicalType(SqlTypes.TIME).withNullable(true))
+          .addField("sqlDatetimeValue", 
FieldType.logicalType(SqlTypes.DATETIME).withNullable(true))
+          .addField(
+              "sqlTimestampValue", 
FieldType.logicalType(SqlTypes.TIMESTAMP).withNullable(true))
+          .addField("enumValue", 
FieldType.logicalType(TEST_ENUM).withNullable(true))
+          .build();
+
+  private static final DescriptorProto BASE_SCHEMA_PROTO =
+      DescriptorProto.newBuilder()
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("bytevalue")
+                  .setNumber(1)
+                  .setType(Type.TYPE_INT32)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("int16value")
+                  .setNumber(2)
+                  .setType(Type.TYPE_INT32)
+                  .setLabel(Label.LABEL_REQUIRED)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("int32value")
+                  .setNumber(3)
+                  .setType(Type.TYPE_INT32)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("int64value")
+                  .setNumber(4)
+                  .setType(Type.TYPE_INT64)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("decimalvalue")
+                  .setNumber(5)
+                  .setType(Type.TYPE_BYTES)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("floatvalue")
+                  .setNumber(6)
+                  .setType(Type.TYPE_FLOAT)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("doublevalue")
+                  .setNumber(7)
+                  .setType(Type.TYPE_DOUBLE)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("stringvalue")
+                  .setNumber(8)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("datetimevalue")
+                  .setNumber(9)
+                  .setType(Type.TYPE_INT64)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("booleanvalue")
+                  .setNumber(10)
+                  .setType(Type.TYPE_BOOL)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("bytesvalue")
+                  .setNumber(11)
+                  .setType(Type.TYPE_BYTES)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("arrayvalue")
+                  .setNumber(12)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_REPEATED)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("iterablevalue")
+                  .setNumber(13)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_REPEATED)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("sqldatevalue")
+                  .setNumber(14)
+                  .setType(Type.TYPE_INT32)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("sqltimevalue")
+                  .setNumber(15)
+                  .setType(Type.TYPE_INT64)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("sqldatetimevalue")
+                  .setNumber(16)
+                  .setType(Type.TYPE_INT64)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("sqltimestampvalue")
+                  .setNumber(17)
+                  .setType(Type.TYPE_INT64)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("enumvalue")
+                  .setNumber(18)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .build();
+
+  private static final byte[] BYTES = "BYTE BYTE 
BYTE".getBytes(StandardCharsets.UTF_8);
+  private static final Row BASE_ROW =
+      Row.withSchema(BASE_SCHEMA)
+          .withFieldValue("byteValue", (byte) 1)
+          .withFieldValue("int16Value", (short) 2)
+          .withFieldValue("int32Value", (int) 3)
+          .withFieldValue("int64Value", (long) 4)
+          .withFieldValue("decimalValue", BigDecimal.valueOf(5))
+          .withFieldValue("floatValue", (float) 3.14)
+          .withFieldValue("doubleValue", (double) 2.68)
+          .withFieldValue("stringValue", "I am a string. Hear me roar.")
+          .withFieldValue("datetimeValue", Instant.now())
+          .withFieldValue("booleanValue", true)
+          .withFieldValue("bytesValue", BYTES)
+          .withFieldValue("arrayValue", ImmutableList.of("one", "two", "red", 
"blue"))
+          .withFieldValue("iterableValue", ImmutableList.of("blue", "red", 
"two", "one"))
+          .withFieldValue("sqlDateValue", LocalDate.now())
+          .withFieldValue("sqlTimeValue", LocalTime.now())
+          .withFieldValue("sqlDatetimeValue", LocalDateTime.now())
+          .withFieldValue("sqlTimestampValue", java.time.Instant.now())
+          .withFieldValue("enumValue", TEST_ENUM.valueOf("RED"))
+          .build();
+  private static final Map<String, Object> BASE_PROTO_EXPECTED_FIELDS =
+      ImmutableMap.<String, Object>builder()
+          .put("bytevalue", (int) 1)
+          .put("int16value", (int) 2)
+          .put("int32value", (int) 3)
+          .put("int64value", (long) 4)
+          .put(
+              "decimalvalue",
+              
BeamRowToStorageApiProto.serializeBigDecimalToNumeric(BigDecimal.valueOf(5)))
+          .put("floatvalue", (float) 3.14)
+          .put("doublevalue", (double) 2.68)
+          .put("stringvalue", "I am a string. Hear me roar.")
+          .put("datetimevalue", 
BASE_ROW.getDateTime("datetimeValue").getMillis() * 1000)
+          .put("booleanvalue", true)
+          .put("bytesvalue", ByteString.copyFrom(BYTES))
+          .put("arrayvalue", ImmutableList.of("one", "two", "red", "blue"))
+          .put("iterablevalue", ImmutableList.of("blue", "red", "two", "one"))
+          .put(
+              "sqldatevalue",
+              (int) BASE_ROW.getLogicalTypeValue("sqlDateValue", 
LocalDate.class).toEpochDay())
+          .put(
+              "sqltimevalue",
+              CivilTimeEncoder.encodePacked64TimeMicros(
+                  BASE_ROW.getLogicalTypeValue("sqlTimeValue", 
LocalTime.class)))
+          .put(
+              "sqldatetimevalue",
+              CivilTimeEncoder.encodePacked64DatetimeSeconds(
+                  BASE_ROW.getLogicalTypeValue("sqlDatetimeValue", 
LocalDateTime.class)))
+          .put(
+              "sqltimestampvalue",
+              BASE_ROW
+                      .getLogicalTypeValue("sqlTimestampValue", 
java.time.Instant.class)
+                      .toEpochMilli()
+                  * 1000)
+          .put("enumvalue", "RED")
+          .build();
+
+  private static final Schema NESTED_SCHEMA =
+      Schema.builder()
+          .addField("nested", FieldType.row(BASE_SCHEMA).withNullable(true))
+          .addField("nestedArray", FieldType.array(FieldType.row(BASE_SCHEMA)))
+          .addField("nestedIterable", 
FieldType.iterable(FieldType.row(BASE_SCHEMA)))
+          .build();
+  private static final Row NESTED_ROW =
+      Row.withSchema(NESTED_SCHEMA)
+          .withFieldValue("nested", BASE_ROW)
+          .withFieldValue("nestedArray", ImmutableList.of(BASE_ROW, BASE_ROW))
+          .withFieldValue("nestedIterable", ImmutableList.of(BASE_ROW, 
BASE_ROW))
+          .build();
+
+  @Test
+  public void testDescriptorFromSchema() {
+    DescriptorProto descriptor =
+        BeamRowToStorageApiProto.descriptorSchemaFromBeamSchema(BASE_SCHEMA);
+    Map<String, Type> types =
+        descriptor.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    Map<String, Type> expectedTypes =
+        BASE_SCHEMA_PROTO.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    assertEquals(expectedTypes, types);
+
+    Map<String, String> nameMapping =
+        BASE_SCHEMA.getFields().stream()
+            .collect(Collectors.toMap(f -> f.getName().toLowerCase(), 
Field::getName));
+    descriptor
+        .getFieldList()
+        .forEach(
+            p -> {
+              FieldType schemaFieldType =
+                  BASE_SCHEMA.getField(nameMapping.get(p.getName())).getType();
+              Label label =
+                  schemaFieldType.getTypeName().isCollectionType()
+                      ? Label.LABEL_REPEATED
+                      : schemaFieldType.getNullable() ? Label.LABEL_OPTIONAL : 
Label.LABEL_REQUIRED;
+              assertEquals(label, p.getLabel());
+            });
+  }
+
+  @Test
+  public void testNestedFromSchema() {
+    DescriptorProto descriptor =
+        BeamRowToStorageApiProto.descriptorSchemaFromBeamSchema(NESTED_SCHEMA);
+    Map<String, Type> expectedBaseTypes =
+        BASE_SCHEMA_PROTO.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+
+    Map<String, Type> types =
+        descriptor.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    Map<String, String> typeNames =
+        descriptor.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getTypeName));
+    Map<String, Label> typeLabels =
+        descriptor.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getLabel));
+
+    assertEquals(3, types.size());
+
+    Map<String, DescriptorProto> nestedTypes =
+        descriptor.getNestedTypeList().stream()
+            .collect(Collectors.toMap(DescriptorProto::getName, 
Functions.identity()));
+    assertEquals(3, nestedTypes.size());
+    assertEquals(Type.TYPE_MESSAGE, types.get("nested"));
+    assertEquals(Label.LABEL_OPTIONAL, typeLabels.get("nested"));
+    String nestedTypeName1 = typeNames.get("nested");
+    Map<String, Type> nestedTypes1 =
+        nestedTypes.get(nestedTypeName1).getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    assertEquals(expectedBaseTypes, nestedTypes1);
+
+    assertEquals(Type.TYPE_MESSAGE, types.get("nestedarray"));
+    assertEquals(Label.LABEL_REPEATED, typeLabels.get("nestedarray"));
+    String nestedTypeName2 = typeNames.get("nestedarray");
+    Map<String, Type> nestedTypes2 =
+        nestedTypes.get(nestedTypeName2).getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    assertEquals(expectedBaseTypes, nestedTypes2);
+
+    assertEquals(Type.TYPE_MESSAGE, types.get("nestediterable"));
+    assertEquals(Label.LABEL_REPEATED, typeLabels.get("nestediterable"));
+    String nestedTypeName3 = typeNames.get("nestediterable");
+    Map<String, Type> nestedTypes3 =
+        nestedTypes.get(nestedTypeName3).getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    assertEquals(expectedBaseTypes, nestedTypes3);
+  }
+
+  private void assertBaseRecord(DynamicMessage msg) {
+    Map<String, Object> recordFields =
+        msg.getAllFields().entrySet().stream()
+            .collect(
+                Collectors.toMap(entry -> entry.getKey().getName(), entry -> 
entry.getValue()));
+    assertEquals(BASE_PROTO_EXPECTED_FIELDS, recordFields);
+  }
+
+  @Test
+  public void testMessageFromTableRow() throws Exception {
+    Descriptor descriptor = 
BeamRowToStorageApiProto.getDescriptorFromSchema(NESTED_SCHEMA);
+    DynamicMessage msg = 
BeamRowToStorageApiProto.messageFromBeamRow(descriptor, NESTED_ROW);
+    assertEquals(3, msg.getAllFields().size());
+
+    Map<String, FieldDescriptor> fieldDescriptors =
+        descriptor.getFields().stream()
+            .collect(Collectors.toMap(FieldDescriptor::getName, 
Functions.identity()));
+    DynamicMessage nestedMsg = (DynamicMessage) 
msg.getField(fieldDescriptors.get("nested"));
+    assertBaseRecord(nestedMsg);
+  }
+}
diff --git 
a/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtilsTest.java
 
b/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtilsTest.java
index d0d4c31..1c856cc 100644
--- 
a/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtilsTest.java
+++ 
b/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/BigQueryUtilsTest.java
@@ -31,14 +31,6 @@ import static org.junit.Assert.assertThrows;
 import com.google.api.services.bigquery.model.TableFieldSchema;
 import com.google.api.services.bigquery.model.TableRow;
 import com.google.api.services.bigquery.model.TableSchema;
-import com.google.protobuf.ByteString;
-import com.google.protobuf.DescriptorProtos.DescriptorProto;
-import com.google.protobuf.DescriptorProtos.FieldDescriptorProto;
-import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label;
-import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Type;
-import com.google.protobuf.Descriptors.Descriptor;
-import com.google.protobuf.Descriptors.FieldDescriptor;
-import com.google.protobuf.DynamicMessage;
 import java.math.BigDecimal;
 import java.math.RoundingMode;
 import java.nio.ByteBuffer;
@@ -46,13 +38,10 @@ import java.nio.charset.StandardCharsets;
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.LocalTime;
-import java.util.AbstractMap;
 import java.util.Arrays;
 import java.util.Base64;
 import java.util.Collections;
 import java.util.List;
-import java.util.Map;
-import java.util.stream.Collectors;
 import org.apache.avro.Conversions;
 import org.apache.avro.LogicalTypes;
 import org.apache.avro.generic.GenericData;
@@ -64,10 +53,7 @@ import 
org.apache.beam.sdk.schemas.logicaltypes.EnumerationType;
 import org.apache.beam.sdk.schemas.logicaltypes.SqlTypes;
 import org.apache.beam.sdk.schemas.utils.AvroUtils;
 import org.apache.beam.sdk.values.Row;
-import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Functions;
-import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableList;
 import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableMap;
-import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.io.BaseEncoding;
 import org.joda.time.DateTime;
 import org.joda.time.Instant;
 import org.joda.time.chrono.ISOChronology;
@@ -787,250 +773,4 @@ public class BigQueryUtilsTest {
             record, AVRO_ARRAY_ARRAY_TYPE, 
BigQueryUtils.ConversionOptions.builder().build());
     assertEquals(expected, beamRow);
   }
-
-  private static final TableSchema BASE_TABLE_SCHEMA =
-      new TableSchema()
-          .setFields(
-              ImmutableList.<TableFieldSchema>builder()
-                  .add(new 
TableFieldSchema().setType("STRING").setName("stringValue"))
-                  .add(new 
TableFieldSchema().setType("BYTES").setName("bytesValue"))
-                  .add(new 
TableFieldSchema().setType("INT64").setName("int64Value"))
-                  .add(new 
TableFieldSchema().setType("INTEGER").setName("intValue"))
-                  .add(new 
TableFieldSchema().setType("FLOAT64").setName("float64Value"))
-                  .add(new 
TableFieldSchema().setType("FLOAT").setName("floatValue"))
-                  .add(new 
TableFieldSchema().setType("BOOL").setName("boolValue"))
-                  .add(new 
TableFieldSchema().setType("BOOLEAN").setName("booleanValue"))
-                  .add(new 
TableFieldSchema().setType("TIMESTAMP").setName("timestampValue"))
-                  .add(new 
TableFieldSchema().setType("TIME").setName("timeValue"))
-                  .add(new 
TableFieldSchema().setType("DATETIME").setName("datetimeValue"))
-                  .add(new 
TableFieldSchema().setType("DATE").setName("dateValue"))
-                  .build());
-
-  private static final DescriptorProto BASE_TABLE_SCHEMA_PROTO =
-      DescriptorProto.newBuilder()
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("stringValue")
-                  .setNumber(1)
-                  .setType(Type.TYPE_STRING)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("bytesValue")
-                  .setNumber(2)
-                  .setType(Type.TYPE_BYTES)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("int64Value")
-                  .setNumber(3)
-                  .setType(Type.TYPE_INT64)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("intValue")
-                  .setNumber(4)
-                  .setType(Type.TYPE_INT64)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("float64Value")
-                  .setNumber(5)
-                  .setType(Type.TYPE_FLOAT)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("floatValue")
-                  .setNumber(6)
-                  .setType(Type.TYPE_FLOAT)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("boolValue")
-                  .setNumber(7)
-                  .setType(Type.TYPE_BOOL)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("booleanValue")
-                  .setNumber(8)
-                  .setType(Type.TYPE_BOOL)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("timestampValue")
-                  .setNumber(9)
-                  .setType(Type.TYPE_INT64)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("timeValue")
-                  .setNumber(10)
-                  .setType(Type.TYPE_INT64)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("datetimeValue")
-                  .setNumber(11)
-                  .setType(Type.TYPE_INT64)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .addField(
-              FieldDescriptorProto.newBuilder()
-                  .setName("dateValue")
-                  .setNumber(12)
-                  .setType(Type.TYPE_INT32)
-                  .setLabel(Label.LABEL_OPTIONAL)
-                  .build())
-          .build();
-
-  private static final TableSchema NESTED_TABLE_SCHEMA =
-      new TableSchema()
-          .setFields(
-              ImmutableList.<TableFieldSchema>builder()
-                  .add(
-                      new TableFieldSchema()
-                          .setType("STRUCT")
-                          .setName("nestedValue1")
-                          .setFields(BASE_TABLE_SCHEMA.getFields()))
-                  .add(
-                      new TableFieldSchema()
-                          .setType("RECORD")
-                          .setName("nestedValue2")
-                          .setFields(BASE_TABLE_SCHEMA.getFields()))
-                  .build());
-
-  // For now, test that no exceptions are thrown.
-  @Test
-  public void testDescriptorFromTableSchema() {
-    DescriptorProto descriptor = 
BigQueryUtils.descriptorSchemaFromTableSchema(BASE_TABLE_SCHEMA);
-    Map<String, Type> types =
-        descriptor.getFieldList().stream()
-            .collect(
-                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
-    Map<String, Type> expectedTypes =
-        BASE_TABLE_SCHEMA_PROTO.getFieldList().stream()
-            .collect(
-                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
-    assertEquals(expectedTypes, types);
-  }
-
-  @Test
-  public void testNestedFromTableSchema() {
-    DescriptorProto descriptor = 
BigQueryUtils.descriptorSchemaFromTableSchema(NESTED_TABLE_SCHEMA);
-    Map<String, Type> expectedBaseTypes =
-        BASE_TABLE_SCHEMA_PROTO.getFieldList().stream()
-            .collect(
-                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
-
-    Map<String, Type> types =
-        descriptor.getFieldList().stream()
-            .collect(
-                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
-    Map<String, String> typeNames =
-        descriptor.getFieldList().stream()
-            .collect(
-                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getTypeName));
-    assertEquals(2, types.size());
-
-    Map<String, DescriptorProto> nestedTypes =
-        descriptor.getNestedTypeList().stream()
-            .collect(Collectors.toMap(DescriptorProto::getName, 
Functions.identity()));
-    assertEquals(2, nestedTypes.size());
-    assertEquals(Type.TYPE_MESSAGE, types.get("nestedValue1"));
-    String nestedTypeName1 = typeNames.get("nestedValue1");
-    Map<String, Type> nestedTypes1 =
-        nestedTypes.get(nestedTypeName1).getFieldList().stream()
-            .collect(
-                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
-    assertEquals(expectedBaseTypes, nestedTypes1);
-
-    assertEquals(Type.TYPE_MESSAGE, types.get("nestedValue2"));
-    String nestedTypeName2 = typeNames.get("nestedValue2");
-    Map<String, Type> nestedTypes2 =
-        nestedTypes.get(nestedTypeName2).getFieldList().stream()
-            .collect(
-                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
-    assertEquals(expectedBaseTypes, nestedTypes2);
-  }
-
-  @Test
-  public void testRepeatedDescriptorFromTableSchema() {
-    BigQueryUtils.descriptorSchemaFromTableSchema(BASE_TABLE_SCHEMA);
-  }
-
-  private TableRow getBaseRecord() {
-    return new TableRow()
-        .set("stringValue", "string")
-        .set("bytesValue", 
BaseEncoding.base64().encode("string".getBytes(StandardCharsets.UTF_8)))
-        .set("int64Value", 42L)
-        .set("intValue", 43L)
-        .set("float64Value", (float) 2.8168)
-        .set("floatValue", (float) 2.817)
-        .set("boolValue", true)
-        .set("booleanValue", true)
-        .set("timestampValue", 1L)
-        .set("timeValue", 2L)
-        .set("datetimeValue", 3L)
-        .set("dateValue", 4);
-  }
-
-  @Test
-  public void testMessageFromTableRow() throws Exception {
-    TableRow baseRecord = getBaseRecord();
-    Map<String, Object> baseRecordFields = ImmutableMap.copyOf(baseRecord);
-
-    TableRow tableRow =
-        new TableRow().set("nestedValue1", baseRecord).set("nestedValue2", 
baseRecord);
-    Descriptor descriptor = 
BigQueryUtils.getDescriptorFromTableSchema(NESTED_TABLE_SCHEMA);
-    DynamicMessage msg = BigQueryUtils.messageFromTableRow(descriptor, 
tableRow);
-    assertEquals(2, msg.getAllFields().size());
-
-    Map<String, FieldDescriptor> fieldDescriptors =
-        descriptor.getFields().stream()
-            .collect(Collectors.toMap(FieldDescriptor::getName, 
Functions.identity()));
-    DynamicMessage nestedMsg1 = (DynamicMessage) 
msg.getField(fieldDescriptors.get("nestedValue1"));
-    Map<String, Object> nestedMsg1Fields =
-        nestedMsg1.getAllFields().entrySet().stream()
-            .map(
-                entry -> {
-                  if (entry.getKey().getType() == FieldDescriptor.Type.BYTES) {
-                    ByteString byteString = (ByteString) entry.getValue();
-                    return new AbstractMap.SimpleEntry<>(
-                        entry.getKey(), 
BaseEncoding.base64().encode(byteString.toByteArray()));
-                  } else {
-                    return entry;
-                  }
-                })
-            .collect(
-                Collectors.toMap(entry -> entry.getKey().getName(), entry -> 
entry.getValue()));
-    assertEquals(baseRecordFields, nestedMsg1Fields);
-
-    DynamicMessage nestedMsg2 = (DynamicMessage) 
msg.getField(fieldDescriptors.get("nestedValue2"));
-    Map<String, Object> nestedMsg2Fields =
-        nestedMsg2.getAllFields().entrySet().stream()
-            .map(
-                entry -> {
-                  if (entry.getKey().getType() == FieldDescriptor.Type.BYTES) {
-                    ByteString byteString = (ByteString) entry.getValue();
-                    return new AbstractMap.SimpleEntry<>(
-                        entry.getKey(), 
BaseEncoding.base64().encode(byteString.toByteArray()));
-                  } else {
-                    return entry;
-                  }
-                })
-            .collect(
-                Collectors.toMap(entry -> entry.getKey().getName(), entry -> 
entry.getValue()));
-    assertEquals(baseRecordFields, nestedMsg2Fields);
-  }
 }
diff --git 
a/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/TableRowToStorageApiProtoTest.java
 
b/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/TableRowToStorageApiProtoTest.java
new file mode 100644
index 0000000..0acc41f
--- /dev/null
+++ 
b/sdks/java/io/google-cloud-platform/src/test/java/org/apache/beam/sdk/io/gcp/bigquery/TableRowToStorageApiProtoTest.java
@@ -0,0 +1,312 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.io.gcp.bigquery;
+
+import static org.junit.Assert.assertEquals;
+
+import com.google.api.services.bigquery.model.TableFieldSchema;
+import com.google.api.services.bigquery.model.TableRow;
+import com.google.api.services.bigquery.model.TableSchema;
+import com.google.protobuf.ByteString;
+import com.google.protobuf.DescriptorProtos.DescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label;
+import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Type;
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.DynamicMessage;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+import java.util.stream.Collectors;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Functions;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableList;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableMap;
+import 
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.io.BaseEncoding;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+@SuppressWarnings({
+  "nullness" // TODO(https://issues.apache.org/jira/browse/BEAM-10402)
+})
+/** Unit tests for {@link 
org.apache.beam.sdk.io.gcp.bigquery.TableRowToStorageApiProto}. */
+public class TableRowToStorageApiProtoTest {
+  private static final TableSchema BASE_TABLE_SCHEMA =
+      new TableSchema()
+          .setFields(
+              ImmutableList.<TableFieldSchema>builder()
+                  .add(new 
TableFieldSchema().setType("STRING").setName("stringValue"))
+                  .add(new 
TableFieldSchema().setType("BYTES").setName("bytesValue"))
+                  .add(new 
TableFieldSchema().setType("INT64").setName("int64Value"))
+                  .add(new 
TableFieldSchema().setType("INTEGER").setName("intValue"))
+                  .add(new 
TableFieldSchema().setType("FLOAT64").setName("float64Value"))
+                  .add(new 
TableFieldSchema().setType("FLOAT").setName("floatValue"))
+                  .add(new 
TableFieldSchema().setType("BOOL").setName("boolValue"))
+                  .add(new 
TableFieldSchema().setType("BOOLEAN").setName("booleanValue"))
+                  .add(new 
TableFieldSchema().setType("TIMESTAMP").setName("timestampValue"))
+                  .add(new 
TableFieldSchema().setType("TIME").setName("timeValue"))
+                  .add(new 
TableFieldSchema().setType("DATETIME").setName("datetimeValue"))
+                  .add(new 
TableFieldSchema().setType("DATE").setName("dateValue"))
+                  .add(new 
TableFieldSchema().setType("NUMERIC").setName("numericValue"))
+                  .add(
+                      new TableFieldSchema()
+                          .setType("STRING")
+                          .setMode("REPEATED")
+                          .setName("arrayValue"))
+                  .build());
+
+  private static final DescriptorProto BASE_TABLE_SCHEMA_PROTO =
+      DescriptorProto.newBuilder()
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("stringvalue")
+                  .setNumber(1)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("bytesvalue")
+                  .setNumber(2)
+                  .setType(Type.TYPE_BYTES)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("int64value")
+                  .setNumber(3)
+                  .setType(Type.TYPE_INT64)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("intvalue")
+                  .setNumber(4)
+                  .setType(Type.TYPE_INT64)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("float64value")
+                  .setNumber(5)
+                  .setType(Type.TYPE_DOUBLE)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("floatvalue")
+                  .setNumber(6)
+                  .setType(Type.TYPE_DOUBLE)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("boolvalue")
+                  .setNumber(7)
+                  .setType(Type.TYPE_BOOL)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("booleanvalue")
+                  .setNumber(8)
+                  .setType(Type.TYPE_BOOL)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("timestampvalue")
+                  .setNumber(9)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("timevalue")
+                  .setNumber(10)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("datetimevalue")
+                  .setNumber(11)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("datevalue")
+                  .setNumber(12)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("numericvalue")
+                  .setNumber(13)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_OPTIONAL)
+                  .build())
+          .addField(
+              FieldDescriptorProto.newBuilder()
+                  .setName("arrayvalue")
+                  .setNumber(14)
+                  .setType(Type.TYPE_STRING)
+                  .setLabel(Label.LABEL_REPEATED)
+                  .build())
+          .build();
+
+  private static final TableSchema NESTED_TABLE_SCHEMA =
+      new TableSchema()
+          .setFields(
+              ImmutableList.<TableFieldSchema>builder()
+                  .add(
+                      new TableFieldSchema()
+                          .setType("STRUCT")
+                          .setName("nestedValue1")
+                          .setFields(BASE_TABLE_SCHEMA.getFields()))
+                  .add(
+                      new TableFieldSchema()
+                          .setType("RECORD")
+                          .setName("nestedValue2")
+                          .setFields(BASE_TABLE_SCHEMA.getFields()))
+                  .build());
+
+  // For now, test that no exceptions are thrown.
+  @Test
+  public void testDescriptorFromTableSchema() {
+    DescriptorProto descriptor =
+        
TableRowToStorageApiProto.descriptorSchemaFromTableSchema(BASE_TABLE_SCHEMA);
+    Map<String, Type> types =
+        descriptor.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    Map<String, Type> expectedTypes =
+        BASE_TABLE_SCHEMA_PROTO.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    assertEquals(expectedTypes, types);
+  }
+
+  @Test
+  public void testNestedFromTableSchema() {
+    DescriptorProto descriptor =
+        
TableRowToStorageApiProto.descriptorSchemaFromTableSchema(NESTED_TABLE_SCHEMA);
+    Map<String, Type> expectedBaseTypes =
+        BASE_TABLE_SCHEMA_PROTO.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+
+    Map<String, Type> types =
+        descriptor.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    Map<String, String> typeNames =
+        descriptor.getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getTypeName));
+    assertEquals(2, types.size());
+
+    Map<String, DescriptorProto> nestedTypes =
+        descriptor.getNestedTypeList().stream()
+            .collect(Collectors.toMap(DescriptorProto::getName, 
Functions.identity()));
+    assertEquals(2, nestedTypes.size());
+    assertEquals(Type.TYPE_MESSAGE, types.get("nestedvalue1"));
+    String nestedTypeName1 = typeNames.get("nestedvalue1");
+    Map<String, Type> nestedTypes1 =
+        nestedTypes.get(nestedTypeName1).getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    assertEquals(expectedBaseTypes, nestedTypes1);
+
+    assertEquals(Type.TYPE_MESSAGE, types.get("nestedvalue2"));
+    String nestedTypeName2 = typeNames.get("nestedvalue2");
+    Map<String, Type> nestedTypes2 =
+        nestedTypes.get(nestedTypeName2).getFieldList().stream()
+            .collect(
+                Collectors.toMap(FieldDescriptorProto::getName, 
FieldDescriptorProto::getType));
+    assertEquals(expectedBaseTypes, nestedTypes2);
+  }
+
+  @Test
+  public void testRepeatedDescriptorFromTableSchema() {
+    
TableRowToStorageApiProto.descriptorSchemaFromTableSchema(BASE_TABLE_SCHEMA);
+  }
+
+  private static final TableRow BASE_TABLE_ROW =
+      new TableRow()
+          .set("stringValue", "string")
+          .set(
+              "bytesValue", 
BaseEncoding.base64().encode("string".getBytes(StandardCharsets.UTF_8)))
+          .set("int64Value", "42")
+          .set("intValue", "43")
+          .set("float64Value", "2.8168")
+          .set("floatValue", "2.817")
+          .set("boolValue", "true")
+          .set("booleanValue", "true")
+          .set("timestampValue", "43")
+          .set("timeValue", "00:52:07[.123]|[.123456] UTC")
+          .set("datetimeValue", "2019-08-16 00:52:07[.123]|[.123456] UTC")
+          .set("dateValue", "2019-08-16")
+          .set("numericValue", "23.4")
+          .set("arrayValue", ImmutableList.of("hello", "goodbye"));
+
+  private static final Map<String, Object> BASE_ROW_EXPECTED_PROTO_VALUES =
+      ImmutableMap.<String, Object>builder()
+          .put("stringvalue", "string")
+          .put("bytesvalue", 
ByteString.copyFrom("string".getBytes(StandardCharsets.UTF_8)))
+          .put("int64value", (long) 42)
+          .put("intvalue", (long) 43)
+          .put("float64value", (double) 2.8168)
+          .put("floatvalue", (double) 2.817)
+          .put("boolvalue", true)
+          .put("booleanvalue", true)
+          .put("timestampvalue", "43")
+          .put("timevalue", "00:52:07[.123]|[.123456] UTC")
+          .put("datetimevalue", "2019-08-16 00:52:07[.123]|[.123456] UTC")
+          .put("datevalue", "2019-08-16")
+          .put("numericvalue", "23.4")
+          .put("arrayvalue", ImmutableList.of("hello", "goodbye"))
+          .build();
+
+  private void assertBaseRecord(DynamicMessage msg) {
+    Map<String, Object> recordFields =
+        msg.getAllFields().entrySet().stream()
+            .collect(
+                Collectors.toMap(entry -> entry.getKey().getName(), entry -> 
entry.getValue()));
+    assertEquals(BASE_ROW_EXPECTED_PROTO_VALUES, recordFields);
+  }
+
+  @Test
+  public void testMessageFromTableRow() throws Exception {
+    TableRow tableRow =
+        new TableRow().set("nestedValue1", BASE_TABLE_ROW).set("nestedValue2", 
BASE_TABLE_ROW);
+    Descriptor descriptor =
+        
TableRowToStorageApiProto.getDescriptorFromTableSchema(NESTED_TABLE_SCHEMA);
+    DynamicMessage msg = 
TableRowToStorageApiProto.messageFromTableRow(descriptor, tableRow);
+    assertEquals(2, msg.getAllFields().size());
+
+    Map<String, FieldDescriptor> fieldDescriptors =
+        descriptor.getFields().stream()
+            .collect(Collectors.toMap(FieldDescriptor::getName, 
Functions.identity()));
+    assertBaseRecord((DynamicMessage) 
msg.getField(fieldDescriptors.get("nestedvalue1")));
+    assertBaseRecord((DynamicMessage) 
msg.getField(fieldDescriptors.get("nestedvalue2")));
+  }
+}

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