com.metamx.druid.indexer.SortableBytes.java Source code

Introduction

Here is the source code for com.metamx.druid.indexer.SortableBytes.java

Source

/*
 * Druid - a distributed column store.
 * Copyright (C) 2012  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package com.metamx.druid.indexer;

import com.google.common.base.Charsets;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.WritableComparator;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Partitioner;

import java.nio.ByteBuffer;
import java.util.Arrays;

/**
 */
public class SortableBytes {
    private final byte[] groupKey;
    private final byte[] sortKey;

    public SortableBytes(byte[] groupKey, byte[] sortKey) {
        this.groupKey = groupKey;
        this.sortKey = sortKey;

        if ("".equals(sortKey)) {
            throw new IllegalArgumentException();
        }
    }

    public byte[] getGroupKey() {
        return groupKey;
    }

    public byte[] getSortKey() {
        return sortKey;
    }

    public byte[] toBytes() {
        ByteBuffer outBytes = ByteBuffer.wrap(new byte[4 + groupKey.length + sortKey.length]);
        outBytes.putInt(groupKey.length);
        outBytes.put(groupKey);
        outBytes.put(sortKey);
        return outBytes.array();
    }

    public BytesWritable toBytesWritable() {
        return new BytesWritable(toBytes());
    }

    @Override
    public String toString() {
        return "SortableBytes{" + "groupKey='" + new String(groupKey, Charsets.UTF_8) + '\'' + ", sortKey='"
                + new String(sortKey, Charsets.UTF_8) + '\'' + '}';
    }

    public static SortableBytes fromBytes(byte[] bytes) {
        return fromBytes(bytes, 0, bytes.length);
    }

    public static SortableBytes fromBytesWritable(BytesWritable bytes) {
        return fromBytes(bytes.getBytes(), 0, bytes.getLength());
    }

    public static SortableBytes fromBytes(byte[] bytes, int offset, int length) {
        int groupKeySize = ByteBuffer.wrap(bytes, offset, length).getInt();

        int sortKeyOffset = offset + 4 + groupKeySize;
        return new SortableBytes(Arrays.copyOfRange(bytes, offset + 4, sortKeyOffset),
                Arrays.copyOfRange(bytes, sortKeyOffset, offset + length));
    }

    public static void useSortableBytesAsMapOutputKey(Job job) {
        job.setMapOutputKeyClass(BytesWritable.class);
        job.setGroupingComparatorClass(SortableBytesGroupingComparator.class);
        job.setSortComparatorClass(SortableBytesSortingComparator.class);
        job.setPartitionerClass(SortableBytesPartitioner.class);
    }

    public static class SortableBytesGroupingComparator extends WritableComparator {

        protected SortableBytesGroupingComparator() {
            super(BytesWritable.class);
        }

        @Override
        public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
            int b1Length = ByteBuffer.wrap(b1, s1 + 4, l1 - 4).getInt();
            int b2Length = ByteBuffer.wrap(b2, s2 + 4, l2 - 4).getInt();

            final int retVal = compareBytes(b1, s1 + 8, b1Length, b2, s2 + 8, b2Length);

            return retVal;
        }
    }

    public static class SortableBytesSortingComparator extends WritableComparator {

        protected SortableBytesSortingComparator() {
            super(BytesWritable.class);
        }

        @Override
        public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
            int b1Length = ByteBuffer.wrap(b1, s1 + 4, l1 - 4).getInt();
            int b2Length = ByteBuffer.wrap(b2, s2 + 4, l2 - 4).getInt();

            int retVal = compareBytes(b1, s1 + 8, b1Length, b2, s2 + 8, b2Length);

            if (retVal == 0) {
                retVal = compareBytes(b1, s1 + 8 + b1Length, l1 - 8 - b1Length, b2, s2 + 8 + b2Length,
                        l2 - 8 - b2Length);
            }

            return retVal;
        }
    }

    public static class SortableBytesPartitioner extends Partitioner<BytesWritable, Object> {
        @Override
        public int getPartition(BytesWritable bytesWritable, Object o, int numPartitions) {
            final byte[] bytes = bytesWritable.getBytes();
            int length = ByteBuffer.wrap(bytes).getInt();

            return (ByteBuffer.wrap(bytes, 4, length).hashCode() & Integer.MAX_VALUE) % numPartitions;
        }
    }
}