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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,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.iteration.datacache.nonkeyed;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.core.fs.FSDataOutputStream;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.core.fs.Path;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.util.Optional;
/** A class that writes cache data to a target file in given file system. */
@Internal
class FileSegmentWriter implements SegmentWriter {
/** The tool to serialize received records into bytes. */
private final TypeSerializer serializer;
/** The path to the target file. */
private final Path path;
/** The output stream that writes to the target file. */
private final FSDataOutputStream outputStream;
/** A buffer that wraps the output stream to optimize performance. */
private final BufferedOutputStream bufferedOutputStream;
/** The wrapper view of the output stream to be used with TypeSerializer API. */
private final DataOutputView outputView;
/** The number of records added so far. */
private int count;
FileSegmentWriter(TypeSerializer serializer, Path path) throws IOException {
this.serializer = serializer;
this.path = path;
this.outputStream = path.getFileSystem().create(path, FileSystem.WriteMode.NO_OVERWRITE);
this.bufferedOutputStream = new BufferedOutputStream(outputStream);
this.outputView = new DataOutputViewStreamWrapper(bufferedOutputStream);
}
@Override
public boolean addRecord(T record) throws IOException {
if (outputStream.getPos() >= DataCacheWriter.MAX_SEGMENT_SIZE) {
return false;
}
serializer.serialize(record, outputView);
count++;
return true;
}
@Override
public Optional finish() throws IOException {
bufferedOutputStream.flush();
long size = outputStream.getPos();
outputStream.close();
if (count > 0) {
Segment segment = new Segment(path, count, size);
return Optional.of(segment);
} else {
// If there are no records, we tend to directly delete this file
path.getFileSystem().delete(path, false);
return Optional.empty();
}
}
}