yashmayya commented on code in PR #12637:
URL: https://github.com/apache/kafka/pull/12637#discussion_r974127639
##########
connect/api/src/main/java/org/apache/kafka/connect/transforms/Transformation.java:
##########
@@ -24,20 +24,31 @@
/**
* Single message transformation for Kafka Connect record types.
- *
+ * <br/>
* Connectors can be configured with transformations to make lightweight
message-at-a-time modifications.
*/
public interface Transformation<R extends ConnectRecord<R>> extends
Configurable, Closeable {
+ String FIELD_SYNTAX_VERSION_CONFIG = "field.syntax.version";
+ String FIELD_SYNTAX_VERSION_DOC = "Defines the version of the syntax to
access fields. "
+ + "If set to `V1`, then the field paths are limited to access the
elements at the root level of the struct or map."
+ + "If set to `V2`, the syntax will support accessing nested elements.
o access nested elements, "
+ + "dotted notation is used. If dots are already included in the field
name, then backtick pairs "
+ + "can be used to wrap field names containing dots. "
+ + "e.g. to access elements from a struct/map named \"foo.bar\", "
+ + "the following format can be used to access its elements:
\"`foo.bar`.baz\".";
Review Comment:
I think this should be `from a field in a struct/map named ...` instead?
##########
connect/transforms/src/main/java/org/apache/kafka/connect/transforms/ExtractField.java:
##########
@@ -39,33 +41,35 @@
private static final String FIELD_CONFIG = "field";
public static final ConfigDef CONFIG_DEF = new ConfigDef()
- .define(FIELD_CONFIG, ConfigDef.Type.STRING,
ConfigDef.NO_DEFAULT_VALUE, ConfigDef.Importance.MEDIUM, "Field name to
extract.");
+ .define(FIELD_CONFIG, ConfigDef.Type.STRING,
ConfigDef.NO_DEFAULT_VALUE, ConfigDef.Importance.MEDIUM, "Field name to
extract.")
+ .define(FIELD_SYNTAX_VERSION_CONFIG, ConfigDef.Type.STRING,
FIELD_SYNTAX_VERSION_DEFAULT_VALUE, ConfigDef.Importance.HIGH,
FIELD_SYNTAX_VERSION_DOC);
Review Comment:
Could we add a validator here to ensure that `FIELD_SYNTAX_VERSION_CONFIG`
belongs to `FieldSyntaxVersion.values()` (maybe case-insensitive match if
desired)?
##########
connect/transforms/src/main/java/org/apache/kafka/connect/transforms/field/FieldPath.java:
##########
@@ -0,0 +1,377 @@
+/*
+ * 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.kafka.connect.transforms.field;
+
+import org.apache.kafka.connect.data.Field;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.data.Schema.Type;
+import org.apache.kafka.connect.data.SchemaBuilder;
+import org.apache.kafka.connect.data.Struct;
+import org.apache.kafka.connect.transforms.util.SchemaUtil;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+/**
+ * Represents a path to a field within a structure within a Connect key/value
(e.g. Struct or
+ * Map<String, Object>).
+ * <ul>
+ * <li>It follows a dotted notation to represent nested values.</li>
+ * <li>If field names contain dots, can be escaped by wrapping field names
with backticks.</li>
+ * <li>If field names contain dots at wrapping positions (beginning or end of
path, before or after dots), then backticks need to be
+ * escaped by backslash.</li>
+ * </ul>
+ * Paths are calculated once and cached for further access.
+ */
+public class FieldPath {
+
+ private static final String BACKTICK = "`";
+ private static final String DOT = ".";
+ public static final char BACKTICK_CHAR = '`';
+ public static final char DOT_CHAR = '.';
+ public static final char BACKSLASH_CHAR = '\\';
+
+ private static final Map<String, FieldPath> PATHS_CACHE = new HashMap<>();
+
+ private final String[] path;
+
+ public static FieldPath ofV1(String field) {
+ return of(field, FieldSyntaxVersion.V1);
+ }
+
+ public static FieldPath ofV2(String field) {
+ return of(field, FieldSyntaxVersion.V2);
+ }
+
+ /**
+ * If version is V2, then paths are cached for further access.
+ *
+ * @param field field path expression
+ * @param version field syntax version
+ */
+ public static FieldPath of(String field, FieldSyntaxVersion version) {
+ if (field == null || field.isEmpty() ||
version.equals(FieldSyntaxVersion.V1)) {
+ return new FieldPath(field, version);
+ } else {
+ if (PATHS_CACHE.containsKey(field)) {
+ return PATHS_CACHE.get(field);
+ } else {
+ final FieldPath fieldPath = new FieldPath(field, version);
+ PATHS_CACHE.put(field, fieldPath);
+ return fieldPath;
+ }
+ }
+ }
+
+ FieldPath(String path, FieldSyntaxVersion version) {
+ if (path == null || path.isEmpty()) { // empty path
+ this.path = new String[] {};
+ } else {
+ switch (version) {
+ case V1: // backward compatibility
+ this.path = new String[] {path};
+ break;
+ case V2:
+ // if no dots or wrapping backticks are used, then return
path with single step
+ if (!path.contains(DOT)
+ && !(path.startsWith(BACKTICK) && path.endsWith(
+ BACKTICK))) {
+ this.path = new String[] {path};
+ } else {
+ // prepare for tracking path steps
+ final List<String> steps = new ArrayList<>();
+ final StringBuilder s = new StringBuilder(
+ path); // avoid creating new string on changes
Review Comment:
```suggestion
final StringBuilder s = new StringBuilder(path); //
avoid creating new string on changes
```
nit: unnecessary newline
##########
connect/transforms/src/main/java/org/apache/kafka/connect/transforms/field/FieldPath.java:
##########
@@ -0,0 +1,377 @@
+/*
+ * 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.kafka.connect.transforms.field;
+
+import org.apache.kafka.connect.data.Field;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.data.Schema.Type;
+import org.apache.kafka.connect.data.SchemaBuilder;
+import org.apache.kafka.connect.data.Struct;
+import org.apache.kafka.connect.transforms.util.SchemaUtil;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+/**
+ * Represents a path to a field within a structure within a Connect key/value
(e.g. Struct or
+ * Map<String, Object>).
+ * <ul>
+ * <li>It follows a dotted notation to represent nested values.</li>
+ * <li>If field names contain dots, can be escaped by wrapping field names
with backticks.</li>
+ * <li>If field names contain dots at wrapping positions (beginning or end of
path, before or after dots), then backticks need to be
+ * escaped by backslash.</li>
+ * </ul>
+ * Paths are calculated once and cached for further access.
+ */
+public class FieldPath {
+
+ private static final String BACKTICK = "`";
+ private static final String DOT = ".";
+ public static final char BACKTICK_CHAR = '`';
+ public static final char DOT_CHAR = '.';
+ public static final char BACKSLASH_CHAR = '\\';
+
+ private static final Map<String, FieldPath> PATHS_CACHE = new HashMap<>();
+
+ private final String[] path;
+
+ public static FieldPath ofV1(String field) {
+ return of(field, FieldSyntaxVersion.V1);
+ }
+
+ public static FieldPath ofV2(String field) {
+ return of(field, FieldSyntaxVersion.V2);
+ }
+
+ /**
+ * If version is V2, then paths are cached for further access.
+ *
+ * @param field field path expression
+ * @param version field syntax version
+ */
+ public static FieldPath of(String field, FieldSyntaxVersion version) {
+ if (field == null || field.isEmpty() ||
version.equals(FieldSyntaxVersion.V1)) {
+ return new FieldPath(field, version);
+ } else {
+ if (PATHS_CACHE.containsKey(field)) {
+ return PATHS_CACHE.get(field);
+ } else {
+ final FieldPath fieldPath = new FieldPath(field, version);
+ PATHS_CACHE.put(field, fieldPath);
+ return fieldPath;
+ }
+ }
+ }
+
+ FieldPath(String path, FieldSyntaxVersion version) {
+ if (path == null || path.isEmpty()) { // empty path
+ this.path = new String[] {};
+ } else {
+ switch (version) {
+ case V1: // backward compatibility
+ this.path = new String[] {path};
+ break;
+ case V2:
+ // if no dots or wrapping backticks are used, then return
path with single step
+ if (!path.contains(DOT)
+ && !(path.startsWith(BACKTICK) && path.endsWith(
+ BACKTICK))) {
Review Comment:
Why do we need this check?
##########
connect/api/src/main/java/org/apache/kafka/connect/transforms/Transformation.java:
##########
@@ -24,20 +24,31 @@
/**
* Single message transformation for Kafka Connect record types.
- *
+ * <br/>
* Connectors can be configured with transformations to make lightweight
message-at-a-time modifications.
*/
public interface Transformation<R extends ConnectRecord<R>> extends
Configurable, Closeable {
+ String FIELD_SYNTAX_VERSION_CONFIG = "field.syntax.version";
+ String FIELD_SYNTAX_VERSION_DOC = "Defines the version of the syntax to
access fields. "
+ + "If set to `V1`, then the field paths are limited to access the
elements at the root level of the struct or map."
+ + "If set to `V2`, the syntax will support accessing nested elements.
o access nested elements, "
+ + "dotted notation is used. If dots are already included in the field
name, then backtick pairs "
+ + "can be used to wrap field names containing dots. "
+ + "e.g. to access elements from a struct/map named \"foo.bar\", "
+ + "the following format can be used to access its elements:
\"`foo.bar`.baz\".";
+
+ String FIELD_SYNTAX_VERSION_DEFAULT_VALUE = "V1";
Review Comment:
I think this (and the above config too) can be moved to `FieldPath` or
`FieldSyntaxVersion` in the `connect:transforms` subproject since they don't
need to be added to the public interface? And then you can avoid using the
string form "V1" directly here.
Or else, if the intention *is* to add it to the public interface and allow
custom SMT builders to also use this new notation, then should we consider
moving the `FieldPath` and related classes to the `connect:api` subproject?
##########
connect/transforms/src/main/java/org/apache/kafka/connect/transforms/field/FieldPath.java:
##########
@@ -0,0 +1,377 @@
+/*
+ * 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.kafka.connect.transforms.field;
+
+import org.apache.kafka.connect.data.Field;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.data.Schema.Type;
+import org.apache.kafka.connect.data.SchemaBuilder;
+import org.apache.kafka.connect.data.Struct;
+import org.apache.kafka.connect.transforms.util.SchemaUtil;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+/**
+ * Represents a path to a field within a structure within a Connect key/value
(e.g. Struct or
+ * Map<String, Object>).
+ * <ul>
+ * <li>It follows a dotted notation to represent nested values.</li>
+ * <li>If field names contain dots, can be escaped by wrapping field names
with backticks.</li>
+ * <li>If field names contain dots at wrapping positions (beginning or end of
path, before or after dots), then backticks need to be
Review Comment:
```suggestion
* <li>If field names contain backticks at wrapping positions (beginning or
end of path, before or after dots), then backticks need to be
```
##########
connect/transforms/src/main/java/org/apache/kafka/connect/transforms/field/FieldPath.java:
##########
@@ -0,0 +1,377 @@
+/*
+ * 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.kafka.connect.transforms.field;
+
+import org.apache.kafka.connect.data.Field;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.data.Schema.Type;
+import org.apache.kafka.connect.data.SchemaBuilder;
+import org.apache.kafka.connect.data.Struct;
+import org.apache.kafka.connect.transforms.util.SchemaUtil;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+/**
+ * Represents a path to a field within a structure within a Connect key/value
(e.g. Struct or
+ * Map<String, Object>).
+ * <ul>
+ * <li>It follows a dotted notation to represent nested values.</li>
+ * <li>If field names contain dots, can be escaped by wrapping field names
with backticks.</li>
+ * <li>If field names contain dots at wrapping positions (beginning or end of
path, before or after dots), then backticks need to be
+ * escaped by backslash.</li>
+ * </ul>
+ * Paths are calculated once and cached for further access.
+ */
+public class FieldPath {
+
+ private static final String BACKTICK = "`";
+ private static final String DOT = ".";
+ public static final char BACKTICK_CHAR = '`';
+ public static final char DOT_CHAR = '.';
+ public static final char BACKSLASH_CHAR = '\\';
+
+ private static final Map<String, FieldPath> PATHS_CACHE = new HashMap<>();
+
+ private final String[] path;
+
+ public static FieldPath ofV1(String field) {
+ return of(field, FieldSyntaxVersion.V1);
+ }
+
+ public static FieldPath ofV2(String field) {
+ return of(field, FieldSyntaxVersion.V2);
+ }
+
+ /**
+ * If version is V2, then paths are cached for further access.
+ *
+ * @param field field path expression
+ * @param version field syntax version
+ */
+ public static FieldPath of(String field, FieldSyntaxVersion version) {
+ if (field == null || field.isEmpty() ||
version.equals(FieldSyntaxVersion.V1)) {
+ return new FieldPath(field, version);
+ } else {
+ if (PATHS_CACHE.containsKey(field)) {
+ return PATHS_CACHE.get(field);
+ } else {
+ final FieldPath fieldPath = new FieldPath(field, version);
+ PATHS_CACHE.put(field, fieldPath);
+ return fieldPath;
+ }
+ }
+ }
+
+ FieldPath(String path, FieldSyntaxVersion version) {
+ if (path == null || path.isEmpty()) { // empty path
+ this.path = new String[] {};
+ } else {
+ switch (version) {
+ case V1: // backward compatibility
+ this.path = new String[] {path};
+ break;
+ case V2:
+ // if no dots or wrapping backticks are used, then return
path with single step
+ if (!path.contains(DOT)
+ && !(path.startsWith(BACKTICK) && path.endsWith(
+ BACKTICK))) {
+ this.path = new String[] {path};
+ } else {
+ // prepare for tracking path steps
+ final List<String> steps = new ArrayList<>();
+ final StringBuilder s = new StringBuilder(
+ path); // avoid creating new string on changes
+
+ while (s.length() > 0) { // until path is traverse
+ // process backtick pair if any
+ if (s.charAt(0) == BACKTICK_CHAR) {
+ s.deleteCharAt(0);
+
+ // find backtick pair
+ int idx = 0;
+ while (idx >= 0) {
+ idx = s.indexOf(BACKTICK, idx);
+ if (idx == -1) {
+ throw new IllegalArgumentException(
+ "Incomplete backtick pair at
[...]`" + s);
+ }
+ if (idx != s.length() - 1) { // non-global
backtick
+ if (s.charAt(idx + 1) != DOT_CHAR
+ || s.charAt(idx - 1)
+ == BACKSLASH_CHAR) { // not
wrapped or escaped
+ idx++; // move index forward and
keep searching
+ } else { // it's end pair
+ steps.add(
+
checkIncompleteBacktickPair(s.substring(0, idx)));
+ s.delete(0, idx + 2); // rm
backtick and dot
+ break;
+ }
+ } else { // global backtick
Review Comment:
Is a "global" backtick referring to a pair of backticks that wrap the whole
field path? I didn't get why that requires special handling?
##########
connect/api/src/main/java/org/apache/kafka/connect/transforms/Transformation.java:
##########
@@ -24,20 +24,31 @@
/**
* Single message transformation for Kafka Connect record types.
- *
+ * <br/>
* Connectors can be configured with transformations to make lightweight
message-at-a-time modifications.
*/
public interface Transformation<R extends ConnectRecord<R>> extends
Configurable, Closeable {
+ String FIELD_SYNTAX_VERSION_CONFIG = "field.syntax.version";
+ String FIELD_SYNTAX_VERSION_DOC = "Defines the version of the syntax to
access fields. "
+ + "If set to `V1`, then the field paths are limited to access the
elements at the root level of the struct or map."
+ + "If set to `V2`, the syntax will support accessing nested elements.
o access nested elements, "
Review Comment:
```suggestion
+ "If set to `V2`, the syntax will support accessing nested
elements. To access nested elements, "
```
##########
connect/transforms/src/main/java/org/apache/kafka/connect/transforms/field/FieldPath.java:
##########
@@ -0,0 +1,377 @@
+/*
+ * 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.kafka.connect.transforms.field;
+
+import org.apache.kafka.connect.data.Field;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.data.Schema.Type;
+import org.apache.kafka.connect.data.SchemaBuilder;
+import org.apache.kafka.connect.data.Struct;
+import org.apache.kafka.connect.transforms.util.SchemaUtil;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+/**
+ * Represents a path to a field within a structure within a Connect key/value
(e.g. Struct or
+ * Map<String, Object>).
+ * <ul>
+ * <li>It follows a dotted notation to represent nested values.</li>
+ * <li>If field names contain dots, can be escaped by wrapping field names
with backticks.</li>
+ * <li>If field names contain dots at wrapping positions (beginning or end of
path, before or after dots), then backticks need to be
+ * escaped by backslash.</li>
+ * </ul>
+ * Paths are calculated once and cached for further access.
+ */
+public class FieldPath {
+
+ private static final String BACKTICK = "`";
+ private static final String DOT = ".";
+ public static final char BACKTICK_CHAR = '`';
+ public static final char DOT_CHAR = '.';
+ public static final char BACKSLASH_CHAR = '\\';
+
+ private static final Map<String, FieldPath> PATHS_CACHE = new HashMap<>();
+
+ private final String[] path;
+
+ public static FieldPath ofV1(String field) {
+ return of(field, FieldSyntaxVersion.V1);
+ }
+
+ public static FieldPath ofV2(String field) {
+ return of(field, FieldSyntaxVersion.V2);
+ }
Review Comment:
nit: can be package-private if only visible for testing
##########
connect/transforms/src/main/java/org/apache/kafka/connect/transforms/field/FieldPath.java:
##########
@@ -0,0 +1,377 @@
+/*
+ * 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.kafka.connect.transforms.field;
+
+import org.apache.kafka.connect.data.Field;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.data.Schema.Type;
+import org.apache.kafka.connect.data.SchemaBuilder;
+import org.apache.kafka.connect.data.Struct;
+import org.apache.kafka.connect.transforms.util.SchemaUtil;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+/**
+ * Represents a path to a field within a structure within a Connect key/value
(e.g. Struct or
+ * Map<String, Object>).
+ * <ul>
+ * <li>It follows a dotted notation to represent nested values.</li>
+ * <li>If field names contain dots, can be escaped by wrapping field names
with backticks.</li>
+ * <li>If field names contain dots at wrapping positions (beginning or end of
path, before or after dots), then backticks need to be
+ * escaped by backslash.</li>
+ * </ul>
+ * Paths are calculated once and cached for further access.
+ */
+public class FieldPath {
+
+ private static final String BACKTICK = "`";
+ private static final String DOT = ".";
+ public static final char BACKTICK_CHAR = '`';
+ public static final char DOT_CHAR = '.';
+ public static final char BACKSLASH_CHAR = '\\';
+
+ private static final Map<String, FieldPath> PATHS_CACHE = new HashMap<>();
+
+ private final String[] path;
+
+ public static FieldPath ofV1(String field) {
+ return of(field, FieldSyntaxVersion.V1);
+ }
+
+ public static FieldPath ofV2(String field) {
+ return of(field, FieldSyntaxVersion.V2);
+ }
+
+ /**
+ * If version is V2, then paths are cached for further access.
+ *
+ * @param field field path expression
+ * @param version field syntax version
+ */
+ public static FieldPath of(String field, FieldSyntaxVersion version) {
+ if (field == null || field.isEmpty() ||
version.equals(FieldSyntaxVersion.V1)) {
+ return new FieldPath(field, version);
+ } else {
+ if (PATHS_CACHE.containsKey(field)) {
+ return PATHS_CACHE.get(field);
+ } else {
+ final FieldPath fieldPath = new FieldPath(field, version);
+ PATHS_CACHE.put(field, fieldPath);
+ return fieldPath;
+ }
+ }
+ }
+
+ FieldPath(String path, FieldSyntaxVersion version) {
+ if (path == null || path.isEmpty()) { // empty path
+ this.path = new String[] {};
+ } else {
+ switch (version) {
+ case V1: // backward compatibility
+ this.path = new String[] {path};
+ break;
+ case V2:
+ // if no dots or wrapping backticks are used, then return
path with single step
+ if (!path.contains(DOT)
+ && !(path.startsWith(BACKTICK) && path.endsWith(
+ BACKTICK))) {
+ this.path = new String[] {path};
+ } else {
+ // prepare for tracking path steps
+ final List<String> steps = new ArrayList<>();
+ final StringBuilder s = new StringBuilder(
+ path); // avoid creating new string on changes
+
+ while (s.length() > 0) { // until path is traverse
+ // process backtick pair if any
+ if (s.charAt(0) == BACKTICK_CHAR) {
+ s.deleteCharAt(0);
+
+ // find backtick pair
+ int idx = 0;
+ while (idx >= 0) {
+ idx = s.indexOf(BACKTICK, idx);
+ if (idx == -1) {
+ throw new IllegalArgumentException(
+ "Incomplete backtick pair at
[...]`" + s);
+ }
+ if (idx != s.length() - 1) { // non-global
backtick
+ if (s.charAt(idx + 1) != DOT_CHAR
+ || s.charAt(idx - 1)
+ == BACKSLASH_CHAR) { // not
wrapped or escaped
+ idx++; // move index forward and
keep searching
+ } else { // it's end pair
+ steps.add(
+
checkIncompleteBacktickPair(s.substring(0, idx)));
+ s.delete(0, idx + 2); // rm
backtick and dot
+ break;
+ }
+ } else { // global backtick
+
steps.add(checkIncompleteBacktickPair(s.substring(0, idx)));
+ s.delete(0, s.length());
+ break;
+ }
+ }
+ } else { // process path dots
+ final int atDot = s.indexOf(DOT);
+ if (atDot > 0) { // get step and move forward
+
steps.add(checkIncompleteBacktickPair(s.substring(0, atDot)));
+ s.delete(0, atDot + 1);
+ } else { // add all
+
steps.add(checkIncompleteBacktickPair(s.toString()));
+ s.delete(0, s.length());
+ }
+ }
+ }
+
+ this.path = steps.toArray(new String[0]);
+ }
+ break;
+ default:
+ throw new IllegalArgumentException("Unknown syntax
version: " + version);
+ }
+ }
+ }
+
+ private String checkIncompleteBacktickPair(String field) {
Review Comment:
Would it be possible to add a doc comment for this method? Also
`checkIncompleteBacktickPair` seems like a misnomer for a method that is
returning a String
##########
connect/transforms/src/test/java/org/apache/kafka/connect/transforms/field/FieldPathTest.java:
##########
@@ -0,0 +1,183 @@
+/*
+ * 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.kafka.connect.transforms.field;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Collections;
+import java.util.Map;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.data.SchemaBuilder;
+import org.apache.kafka.connect.data.Struct;
+import org.apache.kafka.connect.transforms.util.SchemaUtil;
+import org.junit.jupiter.api.Test;
+
+class FieldPathTest {
+ final static String[] EMPTY_PATH = new String[]{};
+
+ @Test void shouldBuildV1WithDotsAndBacktickPair() {
+ assertArrayEquals(new String[] {"foo.bar.baz"},
FieldPath.ofV1("foo.bar.baz").path());
+ assertArrayEquals(new String[] {"foo.`bar.baz`"},
FieldPath.ofV1("foo.`bar.baz`").path());
+ }
+
+ @Test void shouldBuildV2WithEmptyPath() {
+ assertArrayEquals(EMPTY_PATH, FieldPath.of("",
FieldSyntaxVersion.V2).path());
+ }
+
+ @Test void shouldBuildV2WithNullPath() {
+ assertArrayEquals(EMPTY_PATH, FieldPath.of(null,
FieldSyntaxVersion.V2).path());
+ }
+
+ @Test void shouldBuildV2WithoutDots() {
+ assertArrayEquals(new String[] {"foobarbaz"},
FieldPath.of("foobarbaz", FieldSyntaxVersion.V2).path());
+ }
+ @Test void shouldBuildV2WithoutWrappingBackticks() {
+ assertArrayEquals(new String[] {"foo`bar`baz"},
FieldPath.of("foo`bar`baz", FieldSyntaxVersion.V2).path());
+ }
+
+ @Test void shouldBuildV2WhenIncludesDots() {
+ assertArrayEquals(new String[] {"foo", "bar", "baz"},
FieldPath.of("foo.bar.baz", FieldSyntaxVersion.V2).path());
+ }
+
+ @Test void shouldBuildV2WhenIncludesDotsAndBacktickPair() {
+ assertArrayEquals(new String[] {"foo", "bar.baz"},
FieldPath.of("foo.`bar.baz`", FieldSyntaxVersion.V2).path());
+ assertArrayEquals(new String[] {"foo", "bar", "baz"},
FieldPath.of("foo.`bar`.baz", FieldSyntaxVersion.V2).path());
+ }
+
+ @Test void shouldBuildV2AndIgnoreBackticksThatAreNotWrapping() {
+ assertArrayEquals(new String[] {"foo", "ba`r.baz"},
FieldPath.of("foo.`ba`r.baz`", FieldSyntaxVersion.V2).path());
+ assertArrayEquals(new String[] {"foo", "ba`r", "baz"},
FieldPath.of("foo.ba`r.baz", FieldSyntaxVersion.V2).path());
+ }
+
+ @Test void shouldBuildV2AndEscapeBackticks() {
+ assertArrayEquals(new String[] {"foo", "bar`.`baz"},
FieldPath.of("foo.`bar\\`.\\`baz`", FieldSyntaxVersion.V2).path());
+ assertArrayEquals(new String[] {"foo", "bar\\`.`baz"},
FieldPath.of("foo.`bar\\\\`.\\`baz`", FieldSyntaxVersion.V2).path());
+ }
+
+ @Test void shouldBuildV2WithBackticksWrappingBackticks() {
Review Comment:
The rules defined in the KIP don't seem to include this case (although there
is an example in the subsequent section)?
https://cwiki.apache.org/confluence/display/KAFKA/KIP-821%3A+Connect+Transforms+support+for+nested+structures#KIP821:ConnectTransformssupportfornestedstructures-Rules
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