org.apache.flink.runtime.state.ListDelimitedSerializer 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.runtime.state;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.core.memory.DataInputDeserializer;
import org.apache.flink.core.memory.DataOutputSerializer;
import org.apache.flink.util.FlinkRuntimeException;
import org.apache.flink.util.Preconditions;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
/**
* Encapsulates a logic of serialization and deserialization of a list with a delimiter. Used in the
* savepoint format.
*/
public final class ListDelimitedSerializer {
private static final byte DELIMITER = ',';
private final DataInputDeserializer dataInputView = new DataInputDeserializer();
private final DataOutputSerializer dataOutputView = new DataOutputSerializer(128);
public List deserializeList(byte[] valueBytes, TypeSerializer elementSerializer) {
if (valueBytes == null) {
return null;
}
dataInputView.setBuffer(valueBytes);
List result = new ArrayList<>();
T next;
while ((next = deserializeNextElement(dataInputView, elementSerializer)) != null) {
result.add(next);
}
return result;
}
public byte[] serializeList(List valueList, TypeSerializer elementSerializer)
throws IOException {
dataOutputView.clear();
boolean first = true;
for (T value : valueList) {
Preconditions.checkNotNull(value, "You cannot add null to a value list.");
if (first) {
first = false;
} else {
dataOutputView.write(DELIMITER);
}
elementSerializer.serialize(value, dataOutputView);
}
return dataOutputView.getCopyOfBuffer();
}
/** Deserializes a single element from a serialized list. */
public static T deserializeNextElement(
DataInputDeserializer in, TypeSerializer elementSerializer) {
try {
if (in.available() > 0) {
T element = elementSerializer.deserialize(in);
if (in.available() > 0) {
in.readByte();
}
return element;
}
} catch (IOException e) {
throw new FlinkRuntimeException("Unexpected list element deserialization failure", e);
}
return null;
}
}