org.apache.flink.runtime.state.NonClosingCheckpointOutputStream 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.util.Preconditions;
import java.io.IOException;
import java.io.OutputStream;
/**
* Abstract class to implement custom checkpoint output streams which should not be closable for user code.
*
* @param type of the returned state handle.
*/
public abstract class NonClosingCheckpointOutputStream extends OutputStream {
protected final CheckpointStreamFactory.CheckpointStateOutputStream delegate;
public NonClosingCheckpointOutputStream(
CheckpointStreamFactory.CheckpointStateOutputStream delegate) {
this.delegate = Preconditions.checkNotNull(delegate);
}
@Override
public void flush() throws IOException {
delegate.flush();
}
@Override
public void write(int b) throws IOException {
delegate.write(b);
}
@Override
public void write(byte[] b) throws IOException {
delegate.write(b);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
delegate.write(b, off, len);
}
@Override
public void close() throws IOException {
// users should not be able to actually close the stream, it is closed by the system.
// TODO if we want to support async writes, this call could trigger a callback to the snapshot context that a handle is available.
}
/**
* This method should not be public so as to not expose internals to user code.
*/
CheckpointStreamFactory.CheckpointStateOutputStream getDelegate() {
return delegate;
}
/**
* This method should not be public so as to not expose internals to user code. Closes the underlying stream and
* returns a state handle.
*/
abstract T closeAndGetHandle() throws IOException;
}