[FLINK-3872] [table, connector-kafka] Add JsonRowDeserializationSchema

- Adds a deserialization schema from byte[] to Row to be used in conjunction
  with the Table API.

flink-streaming-connectors/flink-connector-kafka-base/pom.xml

@@ -49,6 +49,16 @@ under the License.
 			<scope>provided</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>org.apache.flink</groupId>
+			<artifactId>flink-table_2.10</artifactId>
+			<version>${project.version}</version>
+			<scope>provided</scope>
+			<!-- Projects depending on this project,
+			won't depend on flink-table. -->
+			<optional>true</optional>
+		</dependency>
+
 		<dependency>
 			<groupId>org.apache.kafka</groupId>
 			<artifactId>kafka_${scala.binary.version}</artifactId>
@@ -101,7 +111,6 @@ under the License.
 			<type>jar</type>
 		</dependency>
 
-
 		<dependency>
 			<groupId>org.apache.curator</groupId>
 			<artifactId>curator-test</artifactId>
@@ -124,7 +133,6 @@ under the License.
 			<type>test-jar</type>
 			<scope>test</scope>
 		</dependency>
-
 	</dependencies>
 
 	<dependencyManagement>

flink-streaming-connectors/flink-connector-kafka-base/src/main/java/org/apache/flink/streaming/util/serialization/JsonRowDeserializationSchema.java

+/*
+ * 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.flink.streaming.util.serialization;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.api.table.Row;
+import org.apache.flink.api.table.typeutils.RowTypeInfo;
+import org.apache.flink.util.Preconditions;
+
+import java.io.IOException;
+
+/**
+ * Deserialization schema from JSON to {@link Row}.
+ *
+ * <p>Deserializes the <code>byte[]</code> messages as a JSON object and reads
+ * the specified fields.
+ *
+ * <p>Failure during deserialization are forwarded as wrapped IOExceptions.
+ */
+public class JsonRowDeserializationSchema implements DeserializationSchema<Row> {
+
+	/** Field names to parse. Indices match fieldTypes indices. */
+	private final String[] fieldNames;
+
+	/** Types to parse fields as. Indices match fieldNames indices. */
+	private final TypeInformation<?>[] fieldTypes;
+
+	/** Object mapper for parsing the JSON. */
+	private final ObjectMapper objectMapper = new ObjectMapper();
+
+	/** Flag indicating whether to fail on a missing field. */
+	private boolean failOnMissingField;
+
+	/**
+	 * Creates a JSON deserializtion schema for the given fields and type classes.
+	 *
+	 * @param fieldNames Names of JSON fields to parse.
+	 * @param fieldTypes Type classes to parse JSON fields as.
+	 */
+	public JsonRowDeserializationSchema(String[] fieldNames, Class<?>[] fieldTypes) {
+		this.fieldNames = Preconditions.checkNotNull(fieldNames, "Field names");
+
+		this.fieldTypes = new TypeInformation[fieldTypes.length];
+		for (int i = 0; i < fieldTypes.length; i++) {
+			this.fieldTypes[i] = TypeExtractor.getForClass(fieldTypes[i]);
+		}
+
+		Preconditions.checkArgument(fieldNames.length == fieldTypes.length,
+				"Number of provided field names and types does not match.");
+	}
+
+	/**
+	 * Creates a JSON deserializtion schema for the given fields and types.
+	 *
+	 * @param fieldNames Names of JSON fields to parse.
+	 * @param fieldTypes Types to parse JSON fields as.
+	 */
+	public JsonRowDeserializationSchema(String[] fieldNames, TypeInformation<?>[] fieldTypes) {
+		this.fieldNames = Preconditions.checkNotNull(fieldNames, "Field names");
+		this.fieldTypes = Preconditions.checkNotNull(fieldTypes, "Field types");
+
+		Preconditions.checkArgument(fieldNames.length == fieldTypes.length,
+				"Number of provided field names and types does not match.");
+	}
+
+	@Override
+	public Row deserialize(byte[] message) throws IOException {
+		try {
+			JsonNode root = objectMapper.readTree(message);
+
+			Row row = new Row(fieldNames.length);
+			for (int i = 0; i < fieldNames.length; i++) {
+				JsonNode node = root.get(fieldNames[i]);
+
+				if (node == null) {
+					if (failOnMissingField) {
+						throw new IllegalStateException("Failed to find field with name '"
+								+ fieldNames[i] + "'.");
+					} else {
+						row.setField(i, null);
+					}
+				} else {
+					// Read the value as specified type
+					Object value = objectMapper.treeToValue(node, fieldTypes[i].getTypeClass());
+					row.setField(i, value);
+				}
+			}
+
+			return row;
+		} catch (Throwable t) {
+			throw new IOException("Failed to deserialize JSON object.", t);
+		}
+	}
+
+	@Override
+	public boolean isEndOfStream(Row nextElement) {
+		return false;
+	}
+
+	@Override
+	public TypeInformation<Row> getProducedType() {
+		return new RowTypeInfo(fieldTypes, fieldNames);
+	}
+
+	/**
+	 * Configures the failure behaviour if a JSON field is missing.
+	 *
+	 * <p>By default, a missing field is ignored and the field is set to null.
+	 *
+	 * @param failOnMissingField Flag indicating whether to fail or not on a missing field.
+	 */
+	public void setFailOnMissingField(boolean failOnMissingField) {
+		this.failOnMissingField = failOnMissingField;
+	}
+
+}

flink-streaming-connectors/flink-connector-kafka-base/src/test/java/org/apache/flink/streaming/connectors/kafka/JsonRowDeserializationSchemaTest.java

+/*
+ * 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.flink.streaming.connectors.kafka;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.apache.flink.api.table.Row;
+import org.apache.flink.streaming.util.serialization.JsonRowDeserializationSchema;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.concurrent.ThreadLocalRandom;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+public class JsonRowDeserializationSchemaTest {
+
+	/**
+	 * Tests simple deserialization.
+	 */
+	@Test
+	public void testDeserialization() throws Exception {
+		long id = 1238123899121L;
+		String name = "asdlkjasjkdla998y1122";
+		byte[] bytes = new byte[1024];
+		ThreadLocalRandom.current().nextBytes(bytes);
+
+		ObjectMapper objectMapper = new ObjectMapper();
+
+		// Root
+		ObjectNode root = objectMapper.createObjectNode();
+		root.put("id", id);
+		root.put("name", name);
+		root.put("bytes", bytes);
+
+		byte[] serializedJson = objectMapper.writeValueAsBytes(root);
+
+		JsonRowDeserializationSchema deserializationSchema = new JsonRowDeserializationSchema(
+				new String[] { "id", "name", "bytes" },
+				new Class<?>[] { Long.class, String.class, byte[].class });
+
+		Row deserialized = deserializationSchema.deserialize(serializedJson);
+
+		assertEquals(3, deserialized.productArity());
+		assertEquals(id, deserialized.productElement(0));
+		assertEquals(name, deserialized.productElement(1));
+		assertArrayEquals(bytes, (byte[]) deserialized.productElement(2));
+	}
+
+	/**
+	 * Tests deserialization with non-existing field name.
+	 */
+	@Test
+	public void testMissingNode() throws Exception {
+		ObjectMapper objectMapper = new ObjectMapper();
+
+		// Root
+		ObjectNode root = objectMapper.createObjectNode();
+		root.put("id", 123123123);
+		byte[] serializedJson = objectMapper.writeValueAsBytes(root);
+
+		JsonRowDeserializationSchema deserializationSchema = new JsonRowDeserializationSchema(
+				new String[] { "name" },
+				new Class<?>[] { String.class });
+
+		Row row = deserializationSchema.deserialize(serializedJson);
+
+		assertEquals(1, row.productArity());
+		assertNull("Missing field not null", row.productElement(0));
+
+		deserializationSchema.setFailOnMissingField(true);
+
+		try {
+			deserializationSchema.deserialize(serializedJson);
+			fail("Did not throw expected Exception");
+		} catch (IOException e) {
+			assertTrue(e.getCause() instanceof IllegalStateException);
+		}
+	}
+
+	/**
+	 * Tests that number of field names and types has to match.
+	 */
+	@Test
+	public void testNumberOfFieldNamesAndTypesMismatch() throws Exception {
+		try {
+			new JsonRowDeserializationSchema(
+					new String[] { "one", "two", "three" },
+					new Class<?>[] { Long.class });
+			fail("Did not throw expected Exception");
+		} catch (IllegalArgumentException ignored) {
+			// Expected
+		}
+
+		try {
+			new JsonRowDeserializationSchema(
+					new String[] { "one" },
+					new Class<?>[] { Long.class, String.class });
+			fail("Did not throw expected Exception");
+		} catch (IllegalArgumentException ignored) {
+			// Expected
+		}
+	}
+}