org.apache.flink.formats.json.JsonRowSerializationSchema Maven / Gradle / Ivy
/*
* 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.formats.json;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.serialization.SerializationSchema;
import org.apache.flink.api.common.typeinfo.BasicArrayTypeInfo;
import org.apache.flink.api.common.typeinfo.PrimitiveArrayTypeInfo;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.api.java.typeutils.ObjectArrayTypeInfo;
import org.apache.flink.api.java.typeutils.RowTypeInfo;
import org.apache.flink.types.Row;
import org.apache.flink.util.Preconditions;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.JsonNode;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.node.ArrayNode;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.node.ContainerNode;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.node.ObjectNode;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.sql.Time;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
/**
* Serialization schema that serializes an object of Flink types into a JSON bytes.
*
* Serializes the input Flink object into a JSON string and
* converts it into byte[].
*
*
Result byte[] messages can be deserialized using {@link JsonRowDeserializationSchema}.
*/
@PublicEvolving
public class JsonRowSerializationSchema implements SerializationSchema {
private static final long serialVersionUID = -2885556750743978636L;
/** Type information describing the input type. */
private final TypeInformation typeInfo;
/** Object mapper that is used to create output JSON objects. */
private final ObjectMapper mapper = new ObjectMapper();
/** Formatter for RFC 3339-compliant string representation of a time value (with UTC timezone, without milliseconds). */
private SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss'Z'");
/** Formatter for RFC 3339-compliant string representation of a time value (with UTC timezone). */
private SimpleDateFormat timeFormatWithMillis = new SimpleDateFormat("HH:mm:ss.SSS'Z'");
/** Formatter for RFC 3339-compliant string representation of a timestamp value (with UTC timezone). */
private SimpleDateFormat timestampFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
/** Reusable object node. */
private transient ObjectNode node;
/**
* Creates a JSON serialization schema for the given type information.
*
* @param typeInfo The field names of {@link Row} are used to map to JSON properties.
*/
public JsonRowSerializationSchema(TypeInformation typeInfo) {
Preconditions.checkNotNull(typeInfo, "Type information");
this.typeInfo = typeInfo;
}
/**
* Creates a JSON serialization schema for the given JSON schema.
*
* @param jsonSchema JSON schema describing the result type
*
* @see http://json-schema.org/
*/
public JsonRowSerializationSchema(String jsonSchema) {
this(JsonSchemaConverter.convert(jsonSchema));
}
@Override
public byte[] serialize(Row row) {
if (node == null) {
node = mapper.createObjectNode();
}
try {
convertRow(node, (RowTypeInfo) typeInfo, row);
return mapper.writeValueAsBytes(node);
} catch (Throwable t) {
throw new RuntimeException("Could not serialize row '" + row + "'. " +
"Make sure that the schema matches the input.", t);
}
}
// --------------------------------------------------------------------------------------------
private ObjectNode convertRow(ObjectNode reuse, RowTypeInfo info, Row row) {
if (reuse == null) {
reuse = mapper.createObjectNode();
}
final String[] fieldNames = info.getFieldNames();
final TypeInformation[] fieldTypes = info.getFieldTypes();
// validate the row
if (row.getArity() != fieldNames.length) {
throw new IllegalStateException(String.format(
"Number of elements in the row '%s' is different from number of field names: %d", row, fieldNames.length));
}
for (int i = 0; i < fieldNames.length; i++) {
final String name = fieldNames[i];
final JsonNode fieldConverted = convert(reuse, reuse.get(name), fieldTypes[i], row.getField(i));
reuse.set(name, fieldConverted);
}
return reuse;
}
private JsonNode convert(ContainerNode container, JsonNode reuse, TypeInformation info, Object object) {
if (info == Types.VOID || object == null) {
return container.nullNode();
} else if (info == Types.BOOLEAN) {
return container.booleanNode((Boolean) object);
} else if (info == Types.STRING) {
return container.textNode((String) object);
} else if (info == Types.BIG_DEC) {
// convert decimal if necessary
if (object instanceof BigDecimal) {
return container.numberNode((BigDecimal) object);
}
return container.numberNode(BigDecimal.valueOf(((Number) object).doubleValue()));
} else if (info == Types.BIG_INT) {
// convert integer if necessary
if (object instanceof BigInteger) {
return container.numberNode((BigInteger) object);
}
return container.numberNode(BigInteger.valueOf(((Number) object).longValue()));
} else if (info == Types.SQL_DATE) {
return container.textNode(object.toString());
} else if (info == Types.SQL_TIME) {
final Time time = (Time) object;
// strip milliseconds if possible
if (time.getTime() % 1000 > 0) {
return container.textNode(timeFormatWithMillis.format(time));
}
return container.textNode(timeFormat.format(time));
} else if (info == Types.SQL_TIMESTAMP) {
return container.textNode(timestampFormat.format((Timestamp) object));
} else if (info instanceof RowTypeInfo) {
if (reuse != null && reuse instanceof ObjectNode) {
return convertRow((ObjectNode) reuse, (RowTypeInfo) info, (Row) object);
} else {
return convertRow(null, (RowTypeInfo) info, (Row) object);
}
} else if (info instanceof ObjectArrayTypeInfo) {
if (reuse != null && reuse instanceof ArrayNode) {
return convertObjectArray((ArrayNode) reuse, ((ObjectArrayTypeInfo) info).getComponentInfo(), (Object[]) object);
} else {
return convertObjectArray(null, ((ObjectArrayTypeInfo) info).getComponentInfo(), (Object[]) object);
}
} else if (info instanceof BasicArrayTypeInfo) {
if (reuse != null && reuse instanceof ArrayNode) {
return convertObjectArray((ArrayNode) reuse, ((BasicArrayTypeInfo) info).getComponentInfo(), (Object[]) object);
} else {
return convertObjectArray(null, ((BasicArrayTypeInfo) info).getComponentInfo(), (Object[]) object);
}
} else if (info instanceof PrimitiveArrayTypeInfo && ((PrimitiveArrayTypeInfo) info).getComponentType() == Types.BYTE) {
return container.binaryNode((byte[]) object);
} else {
// for types that were specified without JSON schema
// e.g. POJOs
try {
return mapper.valueToTree(object);
} catch (IllegalArgumentException e) {
throw new IllegalStateException("Unsupported type information '" + info + "' for object: " + object, e);
}
}
}
private ArrayNode convertObjectArray(ArrayNode reuse, TypeInformation info, Object[] array) {
if (reuse == null) {
reuse = mapper.createArrayNode();
} else {
reuse.removeAll();
}
for (Object object : array) {
reuse.add(convert(reuse, null, info, object));
}
return reuse;
}
}