org.apache.flink.runtime.state.RetrievableStreamStateHandle Maven / Gradle / Ivy
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* 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.core.fs.FSDataInputStream;
import org.apache.flink.core.fs.Path;
import org.apache.flink.runtime.state.filesystem.FileStateHandle;
import org.apache.flink.util.InstantiationUtil;
import org.apache.flink.util.Preconditions;
import java.io.Closeable;
import java.io.IOException;
import java.io.Serializable;
/**
* Wrapper around a {@link StreamStateHandle} to make the referenced state object retrievable trough a simple get call.
* This implementation expects that the object was serialized through default serialization of Java's
* {@link java.io.ObjectOutputStream}.
*
* @param type of the retrievable object which is stored under the wrapped stream handle
*/
public class RetrievableStreamStateHandle implements
StreamStateHandle, RetrievableStateHandle, Closeable {
private static final long serialVersionUID = 314567453677355L;
/** wrapped inner stream state handle from which we deserialize on retrieval */
private final StreamStateHandle wrappedStreamStateHandle;
public RetrievableStreamStateHandle(StreamStateHandle streamStateHandle) {
this.wrappedStreamStateHandle = Preconditions.checkNotNull(streamStateHandle);
}
public RetrievableStreamStateHandle(Path filePath, long stateSize) {
Preconditions.checkNotNull(filePath);
this.wrappedStreamStateHandle = new FileStateHandle(filePath, stateSize);
}
@Override
public T retrieveState() throws IOException, ClassNotFoundException {
try (FSDataInputStream in = openInputStream()) {
return InstantiationUtil.deserializeObject(in, Thread.currentThread().getContextClassLoader());
}
}
@Override
public FSDataInputStream openInputStream() throws IOException {
return wrappedStreamStateHandle.openInputStream();
}
@Override
public void discardState() throws Exception {
wrappedStreamStateHandle.discardState();
}
@Override
public long getStateSize() {
return wrappedStreamStateHandle.getStateSize();
}
@Override
public void close() throws IOException {
// wrappedStreamStateHandle.close();
}
}