Github user JPercivall commented on a diff in the pull request:
https://github.com/apache/nifi/pull/645#discussion_r71074419
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/AbstractDatabaseFetchProcessor.java
---
@@ -0,0 +1,361 @@
+/*
+ * 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.nifi.processors.standard;
+
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.dbcp.DBCPService;
+import org.apache.nifi.processor.AbstractSessionFactoryProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.util.StandardValidators;
+import org.apache.nifi.processors.standard.db.DatabaseAdapter;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Timestamp;
+import java.text.DecimalFormat;
+import java.text.ParseException;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.ServiceLoader;
+import java.util.Set;
+
+import static java.sql.Types.ARRAY;
+import static java.sql.Types.BIGINT;
+import static java.sql.Types.BINARY;
+import static java.sql.Types.BIT;
+import static java.sql.Types.BLOB;
+import static java.sql.Types.BOOLEAN;
+import static java.sql.Types.CLOB;
+import static java.sql.Types.DECIMAL;
+import static java.sql.Types.DOUBLE;
+import static java.sql.Types.FLOAT;
+import static java.sql.Types.INTEGER;
+import static java.sql.Types.LONGVARBINARY;
+import static java.sql.Types.NUMERIC;
+import static java.sql.Types.CHAR;
+import static java.sql.Types.DATE;
+import static java.sql.Types.LONGNVARCHAR;
+import static java.sql.Types.LONGVARCHAR;
+import static java.sql.Types.NCHAR;
+import static java.sql.Types.NVARCHAR;
+import static java.sql.Types.REAL;
+import static java.sql.Types.ROWID;
+import static java.sql.Types.SMALLINT;
+import static java.sql.Types.TIME;
+import static java.sql.Types.TIMESTAMP;
+import static java.sql.Types.TINYINT;
+import static java.sql.Types.VARBINARY;
+import static java.sql.Types.VARCHAR;
+
+/**
+ * A base class for common code shared by processors that fetch RDBMS data.
+ */
+public abstract class AbstractDatabaseFetchProcessor extends
AbstractSessionFactoryProcessor {
+
+ // Relationships
+ public static final Relationship REL_SUCCESS = new
Relationship.Builder()
+ .name("success")
+ .description("Successfully created FlowFile from SQL query
result set.")
+ .build();
+
+ protected Set<Relationship> relationships;
+
+ // Properties
+ public static final PropertyDescriptor DBCP_SERVICE = new
PropertyDescriptor.Builder()
+ .name("Database Connection Pooling Service")
+ .description("The Controller Service that is used to obtain a
connection to the database.")
+ .required(true)
+ .identifiesControllerService(DBCPService.class)
+ .build();
+
+ public static final PropertyDescriptor TABLE_NAME = new
PropertyDescriptor.Builder()
+ .name("Table Name")
+ .description("The name of the database table to be queried.")
+ .required(true)
+ .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor COLUMN_NAMES = new
PropertyDescriptor.Builder()
+ .name("Columns to Return")
+ .description("A comma-separated list of column names to be
used in the query. If your database requires "
+ + "special treatment of the names (quoting, e.g.),
each name should include such treatment. If no "
+ + "column names are supplied, all columns in the
specified table will be returned.")
+ .required(false)
+ .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor MAX_VALUE_COLUMN_NAMES = new
PropertyDescriptor.Builder()
+ .name("Maximum-value Columns")
+ .description("A comma-separated list of column names. The
processor will keep track of the maximum value "
+ + "for each column that has been returned since the
processor started running. This can be used to "
+ + "retrieve only those rows that have been
added/updated since the last retrieval. Note that some "
+ + "JDBC types such as bit/boolean are not conducive to
maintaining maximum value, so columns of these "
+ + "types should not be listed in this property, and
will result in error(s) during processing.")
+ .required(false)
+ .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor QUERY_TIMEOUT = new
PropertyDescriptor.Builder()
+ .name("Max Wait Time")
+ .description("The maximum amount of time allowed for a running
SQL select query "
+ + ", zero means there is no limit. Max time less than
1 second will be equal to zero.")
+ .defaultValue("0 seconds")
+ .required(true)
+ .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
+ .build();
+
+ protected List<PropertyDescriptor> propDescriptors;
+
+ public static final PropertyDescriptor DB_TYPE;
+
+ protected final static Map<String, DatabaseAdapter> dbAdapters = new
HashMap<>();
+ protected final Map<String, Integer> columnTypeMap = new HashMap<>();
+
+ static {
+ // Load the DatabaseAdapters
+ ServiceLoader<DatabaseAdapter> dbAdapterLoader =
ServiceLoader.load(DatabaseAdapter.class);
+ dbAdapterLoader.forEach(it -> dbAdapters.put(it.getName(), it));
+
+ DB_TYPE = new PropertyDescriptor.Builder()
+ .name("db-fetch-db-type")
+ .displayName("Database Type")
+ .description("The type/flavor of database, used for
generating database-specific code. In many cases the Generic type "
+ + "should suffice, but some databases (such as
Oracle) require custom SQL clauses. ")
+ .allowableValues(dbAdapters.keySet())
+
.defaultValue(dbAdapters.values().stream().findFirst().get().getName())
+ .required(true)
+ .build();
+ }
+
+ public void setup(final ProcessContext context) {
+ // Try to fill the columnTypeMap with the types of the desired
max-value columns
+ final DBCPService dbcpService =
context.getProperty(DBCP_SERVICE).asControllerService(DBCPService.class);
+ final String tableName =
context.getProperty(TABLE_NAME).getValue();
+ final String maxValueColumnNames =
context.getProperty(MAX_VALUE_COLUMN_NAMES).getValue();
+ final DatabaseAdapter dbAdapter =
dbAdapters.get(context.getProperty(DB_TYPE).getValue());
+
+ try (final Connection con = dbcpService.getConnection();
+ final Statement st = con.createStatement()) {
+
+ // Try a query that returns no rows, for the purposes of
getting metadata about the columns. It is possible
+ // to use DatabaseMetaData.getColumns(), but not all drivers
support this, notably the schema-on-read
+ // approach as in Apache Drill
+ String query = dbAdapter.getSelectStatement(tableName,
maxValueColumnNames, "1 = 0", null, null, null);
+ ResultSet resultSet = st.executeQuery(query);
+ ResultSetMetaData resultSetMetaData = resultSet.getMetaData();
+ int numCols = resultSetMetaData.getColumnCount();
+ if (numCols > 0) {
+ columnTypeMap.clear();
+ for (int i = 1; i <= numCols; i++) {
+ String colName =
resultSetMetaData.getColumnName(i).toLowerCase();
+ int colType = resultSetMetaData.getColumnType(i);
+ columnTypeMap.put(colName, colType);
+ }
+
+ } else {
+ throw new ProcessException("No columns found in table from
those specified: " + maxValueColumnNames);
+ }
+
+ } catch (SQLException e) {
+ throw new ProcessException("Unable to communicate with
database in order to determine column types", e);
+ }
+ }
+
+ protected static String getMaxValueFromRow(ResultSet resultSet,
+ int columnIndex,
+ Integer type,
+ String maxValueString,
+ String preProcessStrategy)
+ throws ParseException, IOException, SQLException {
+
+ // Skip any columns we're not keeping track of or whose value is
null
+ if (type == null || resultSet.getObject(columnIndex) == null) {
+ return null;
+ }
+
+ switch (type) {
+ case CHAR:
+ case LONGNVARCHAR:
+ case LONGVARCHAR:
+ case NCHAR:
+ case NVARCHAR:
+ case VARCHAR:
+ case ROWID:
+ String colStringValue = resultSet.getString(columnIndex);
+ if (maxValueString == null ||
colStringValue.compareTo(maxValueString) > 0) {
+ return colStringValue;
+ }
+ break;
+
+ case INTEGER:
+ case SMALLINT:
+ case TINYINT:
+ Integer colIntValue = resultSet.getInt(columnIndex);
+ Integer maxIntValue = null;
+ if (maxValueString != null) {
+ maxIntValue = Integer.valueOf(maxValueString);
+ }
+ if (maxIntValue == null || colIntValue > maxIntValue) {
+ return colIntValue.toString();
+ }
+ break;
+
+ case BIGINT:
+ Long colLongValue = resultSet.getLong(columnIndex);
+ Long maxLongValue = null;
+ if (maxValueString != null) {
+ maxLongValue = Long.valueOf(maxValueString);
+ }
+ if (maxLongValue == null || colLongValue > maxLongValue) {
+ return colLongValue.toString();
+ }
+ break;
+
+ case FLOAT:
+ case REAL:
+ case DOUBLE:
+ Double colDoubleValue = resultSet.getDouble(columnIndex);
+ Double maxDoubleValue = null;
+ if (maxValueString != null) {
+ maxDoubleValue = Double.valueOf(maxValueString);
+ }
+ if (maxDoubleValue == null || colDoubleValue >
maxDoubleValue) {
+ return colDoubleValue.toString();
+ }
+ break;
+
+ case DECIMAL:
+ case NUMERIC:
+ BigDecimal colBigDecimalValue =
resultSet.getBigDecimal(columnIndex);
+ BigDecimal maxBigDecimalValue = null;
+ if (maxValueString != null) {
+ DecimalFormat df = new DecimalFormat();
+ df.setParseBigDecimal(true);
+ maxBigDecimalValue = (BigDecimal)
df.parse(maxValueString);
+ }
+ if (maxBigDecimalValue == null ||
colBigDecimalValue.compareTo(maxBigDecimalValue) > 0) {
+ return colBigDecimalValue.toString();
+ }
+ break;
+
+ case DATE:
+ Date rawColDateValue = resultSet.getDate(columnIndex);
+ java.sql.Date colDateValue = new
java.sql.Date(rawColDateValue.getTime());
+ java.sql.Date maxDateValue = null;
+ if (maxValueString != null) {
+ maxDateValue = java.sql.Date.valueOf(maxValueString);
+ }
+ if (maxDateValue == null ||
colDateValue.after(maxDateValue)) {
+ return colDateValue.toString();
+ }
+ break;
+
+ case TIME:
+ Date rawColTimeValue = resultSet.getDate(columnIndex);
+ java.sql.Time colTimeValue = new
java.sql.Time(rawColTimeValue.getTime());
+ java.sql.Time maxTimeValue = null;
+ if (maxValueString != null) {
+ maxTimeValue = java.sql.Time.valueOf(maxValueString);
+ }
+ if (maxTimeValue == null ||
colTimeValue.after(maxTimeValue)) {
+ return colTimeValue.toString();
+ }
+ break;
+
+ case TIMESTAMP:
+ // Oracle timestamp queries must use literals in
java.sql.Date format
+ if ("Oracle".equals(preProcessStrategy)) {
+ Date rawColOracleTimestampValue =
resultSet.getDate(columnIndex);
+ java.sql.Date oracleTimestampValue = new
java.sql.Date(rawColOracleTimestampValue.getTime());
+ java.sql.Date maxOracleTimestampValue = null;
+ if (maxValueString != null) {
+ maxOracleTimestampValue =
java.sql.Date.valueOf(maxValueString);
+ }
+ if (maxOracleTimestampValue == null ||
oracleTimestampValue.after(maxOracleTimestampValue)) {
+ return oracleTimestampValue.toString();
+ }
+ } else {
+ Timestamp rawColTimestampValue =
resultSet.getTimestamp(columnIndex);
+ java.sql.Timestamp colTimestampValue = new
java.sql.Timestamp(rawColTimestampValue.getTime());
+ java.sql.Timestamp maxTimestampValue = null;
+ if (maxValueString != null) {
+ maxTimestampValue =
java.sql.Timestamp.valueOf(maxValueString);
+ }
+ if (maxTimestampValue == null ||
colTimestampValue.after(maxTimestampValue)) {
+ return colTimestampValue.toString();
+ }
+ }
+ break;
+
+ case BIT:
+ case BOOLEAN:
+ case BINARY:
+ case VARBINARY:
+ case LONGVARBINARY:
+ case ARRAY:
+ case BLOB:
+ case CLOB:
+ default:
+ throw new IOException("Type for column " + columnIndex + "
is not valid for maintaining maximum value");
+ }
+ return null;
+ }
+
+ /**
+ * Returns a SQL literal for the given value based on its type. For
example, values of character type need to be enclosed
+ * in single quotes, whereas values of numeric type should not be.
+ *
+ * @param type The JDBC type for the desired literal
+ * @param value The value to be converted to a SQL literal
+ * @return A String representing the given value as a literal of the
given type
+ */
+ protected static String getLiteralByType(int type, String value,
String preProcessStrategy) {
--- End diff --
The last parameter shouldn't be "preProcessStrategy" since that property
was removed in favor of database type.
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