/
FileChannelOutputView.java
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/
FileChannelOutputView.java
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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.io.disk;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import java.io.IOException;
import java.util.List;
import org.apache.flink.core.memory.MemorySegment;
import org.apache.flink.runtime.io.disk.iomanager.BlockChannelWriter;
import org.apache.flink.runtime.memorymanager.AbstractPagedOutputView;
import org.apache.flink.runtime.memorymanager.MemoryManager;
/**
* A {@link org.apache.flink.core.memory.DataOutputView} that is backed by a {@link BlockChannelWriter}, making it effectively a data output
* stream. The view writes it data in blocks to the underlying channel.
*/
public class FileChannelOutputView extends AbstractPagedOutputView {
private final BlockChannelWriter writer; // the writer to the channel
private final MemoryManager memManager;
private final List<MemorySegment> memory;
private int numBlocksWritten;
private int bytesInLatestSegment;
// --------------------------------------------------------------------------------------------
public FileChannelOutputView(BlockChannelWriter writer, MemoryManager memManager, List<MemorySegment> memory, int segmentSize) throws IOException {
super(segmentSize, 0);
checkNotNull(writer);
checkNotNull(memManager);
checkNotNull(memory);
checkArgument(!writer.isClosed());
this.writer = writer;
this.memManager = memManager;
this.memory = memory;
for (MemorySegment next : memory) {
writer.getReturnQueue().add(next);
}
// move to the first page
advance();
}
// --------------------------------------------------------------------------------------------
/**
* Closes this output, writing pending data and releasing the memory.
*
* @throws IOException Thrown, if the pending data could not be written.
*/
public void close() throws IOException {
close(false);
}
/**
* Closes this output, writing pending data and releasing the memory.
*
* @throws IOException Thrown, if the pending data could not be written.
*/
public void closeAndDelete() throws IOException {
close(true);
}
private void close(boolean delete) throws IOException {
try {
// send off set last segment, if we have not been closed before
MemorySegment current = getCurrentSegment();
if (current != null) {
writeSegment(current, getCurrentPositionInSegment());
}
clear();
if (delete) {
writer.closeAndDelete();
} else {
writer.close();
}
}
finally {
memManager.release(memory);
}
}
// --------------------------------------------------------------------------------------------
/**
* Gets the number of blocks written by this output view.
*
* @return The number of blocks written by this output view.
*/
public int getBlockCount() {
return numBlocksWritten;
}
/**
* Gets the number of bytes written in the latest memory segment.
*
* @return The number of bytes written in the latest memory segment.
*/
public int getBytesInLatestSegment() {
return bytesInLatestSegment;
}
@Override
protected MemorySegment nextSegment(MemorySegment current, int posInSegment) throws IOException {
if (current != null) {
writeSegment(current, posInSegment);
}
return writer.getNextReturnedSegment();
}
private void writeSegment(MemorySegment segment, int writePosition) throws IOException {
writer.writeBlock(segment);
numBlocksWritten++;
bytesInLatestSegment = writePosition;
}
}