org.apache.crunch.lib.sort.ReverseWritableComparator.java Source code

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Here is the source code for org.apache.crunch.lib.sort.ReverseWritableComparator.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.crunch.lib.sort;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.io.RawComparator;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
import org.apache.hadoop.mapred.JobConf;

public class ReverseWritableComparator<T> extends Configured implements RawComparator<T> {

    private RawComparator<T> comparator;

    @SuppressWarnings("unchecked")
    @Override
    public void setConf(Configuration conf) {
        super.setConf(conf);
        if (conf != null) {
            JobConf jobConf = new JobConf(conf);
            comparator = WritableComparator
                    .get(jobConf.getMapOutputKeyClass().asSubclass(WritableComparable.class));
        }
    }

    @Override
    public int compare(byte[] arg0, int arg1, int arg2, byte[] arg3, int arg4, int arg5) {
        return -comparator.compare(arg0, arg1, arg2, arg3, arg4, arg5);
    }

    @Override
    public int compare(T o1, T o2) {
        return -comparator.compare(o1, o2);
    }
}