org.apache.hadoop.hdfs.protocol.HdfsBlocksMetadata.java Source code

Introduction

Here is the source code for org.apache.hadoop.hdfs.protocol.HdfsBlocksMetadata.java

Source

/**
 * 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.hadoop.hdfs.protocol;

import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.primitives.Longs;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

import java.util.List;

/**
 * Augments an array of blocks on a datanode with additional information about
 * where the block is stored.
 */
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class HdfsBlocksMetadata {

    /** The block pool that was queried */
    private final String blockPoolId;

    /**
     * List of blocks
     */
    private final long[] blockIds;

    /**
     * List of volumes
     */
    private final List<byte[]> volumeIds;

    /**
     * List of indexes into <code>volumeIds</code>, one per block in
     * <code>blocks</code>. A value of Integer.MAX_VALUE indicates that the
     * block was not found.
     */
    private final List<Integer> volumeIndexes;

    /**
     * Constructs HdfsBlocksMetadata.
     *
     * @param blockIds
     *     List of blocks described
     * @param volumeIds
     *     List of potential volume identifiers, specifying volumes where
     *     blocks may be stored
     * @param volumeIndexes
     *     Indexes into the list of volume identifiers, one per block
     */
    public HdfsBlocksMetadata(String blockPoolId, long[] blockIds, List<byte[]> volumeIds,
            List<Integer> volumeIndexes) {
        Preconditions.checkArgument(blockIds.length == volumeIndexes.size(), "Argument lengths should match");
        this.blockPoolId = blockPoolId;
        this.blockIds = blockIds;
        this.volumeIds = volumeIds;
        this.volumeIndexes = volumeIndexes;
    }

    /**
     * Get the array of blocks.
     *
     * @return array of blocks
     */
    public long[] getBlockIds() {
        return blockIds;
    }

    /**
     * Get the list of volume identifiers in raw byte form.
     *
     * @return list of ids
     */
    public List<byte[]> getVolumeIds() {
        return volumeIds;
    }

    /**
     * Get a list of indexes into the array of {@link VolumeId}s, one per block.
     *
     * @return list of indexes
     */
    public List<Integer> getVolumeIndexes() {
        return volumeIndexes;
    }

    @Override
    public String toString() {
        return "Metadata for " + blockIds.length + " blocks in " + blockPoolId + ": "
                + Joiner.on(",").join(Longs.asList(blockIds));
    }
}