org.apache.flink.runtime.io.network.partition.external.writer.PartitionIndexGenerator 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.network.partition.external.writer;

import org.apache.flink.runtime.io.network.partition.external.PartitionIndex;

import java.util.ArrayList;
import java.util.List;

/**
 * Maintains the statistics for current partition and generates the partition indices for a partitioned data file.
 */
public class PartitionIndexGenerator {
	private final int numberOfSubpartitions;
	private final List partitionIndices;

	private long lastRecordsWritten = 0;

	private int currentSubpartition = 0;
	private long currentSubpartitionStartOffset = 0;

	public PartitionIndexGenerator(int numberOfSubpartitions) {
		this.numberOfSubpartitions = numberOfSubpartitions;
		this.partitionIndices = new ArrayList<>(numberOfSubpartitions);
	}

	public void updatePartitionIndexBeforeWriting(
		int subpartition, long numBytesWrittenBeforeWriting, long numRecordsWrittenBeforeWriting) {

		if (subpartition != currentSubpartition) {
			PartitionIndex partitionIndex = new PartitionIndex(currentSubpartition, currentSubpartitionStartOffset,
				numBytesWrittenBeforeWriting - currentSubpartitionStartOffset,
				numRecordsWrittenBeforeWriting - lastRecordsWritten);
			partitionIndices.add(partitionIndex);

			for (int i = currentSubpartition + 1; i < subpartition; ++i) {
				partitionIndices.add(new PartitionIndex(i, numBytesWrittenBeforeWriting, 0, 0));
			}

			lastRecordsWritten = numRecordsWrittenBeforeWriting;

			currentSubpartition = subpartition;
			currentSubpartitionStartOffset = numBytesWrittenBeforeWriting;
		}
	}

	public void finishWriting(long numBytesWrittenBefore, long numRecordsWrittenBefore) {
		PartitionIndex partitionIndex = new PartitionIndex(currentSubpartition, currentSubpartitionStartOffset,
			numBytesWrittenBefore - currentSubpartitionStartOffset, numRecordsWrittenBefore - lastRecordsWritten);
		partitionIndices.add(partitionIndex);

		for (int i = currentSubpartition + 1; i < numberOfSubpartitions; ++i) {
			partitionIndices.add(new PartitionIndex(i, numBytesWrittenBefore, 0, 0));
		}
	}

	public List getPartitionIndices() {
		return partitionIndices;
	}
}