org.apache.flink.runtime.io.disk.iomanager.AsynchronousBlockWriter 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.io.disk.iomanager;
import java.io.IOException;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import org.apache.flink.core.memory.MemorySegment;
public class AsynchronousBlockWriter extends AsynchronousBlockWriterWithCallback implements BlockChannelWriter {
private final LinkedBlockingQueue returnSegments;
/**
* Creates a new block channel writer for the given channel.
*
* @param channelID The ID of the channel to write to.
* @param requestScheduler The request scheduler of the asynchronous writer thread, to which the I/O requests
* are added.
* @param returnSegments The return queue, to which the processed Memory Segments are added.
* @param bufferSize -1 mean not use buffered.
* @throws IOException Thrown, if the underlying file channel could not be opened exclusively.
*/
protected AsynchronousBlockWriter(FileIOChannel.ID channelID, IORequestScheduler requestScheduler,
LinkedBlockingQueue returnSegments, int bufferSize)
throws IOException
{
super(channelID, requestScheduler, new QueuingCallback<>(returnSegments), bufferSize);
this.returnSegments = returnSegments;
}
/**
* Gets the next memory segment that has been written and is available again.
* This method blocks until such a segment is available, or until an error occurs in the writer, or the
* writer is closed.
*
* NOTE: If this method is invoked without any segment ever returning (for example, because the
* {@link #writeBlock(MemorySegment)} method has not been invoked accordingly), the method may block
* forever.
*
* @return The next memory segment from the writers's return queue.
* @throws IOException Thrown, if an I/O error occurs in the writer while waiting for the request to return.
*/
@Override
public MemorySegment getNextReturnedBlock() throws IOException {
try {
while (true) {
final MemorySegment next = returnSegments.poll(1000, TimeUnit.MILLISECONDS);
if (next != null) {
return next;
} else {
if (this.closed) {
throw new IOException("The writer has been closed.");
}
checkErroneous();
}
}
} catch (InterruptedException e) {
throw new IOException("Writer was interrupted while waiting for the next returning segment.");
}
}
/**
* Gets the queue in which the memory segments are queued after the asynchronous write is completed.
*
* @return The queue with the written memory segments.
*/
@Override
public LinkedBlockingQueue getReturnQueue() {
return this.returnSegments;
}
}