uk.ac.cam.eng.extraction.hadoop.merge.MergeComparator.java Source code

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Here is the source code for uk.ac.cam.eng.extraction.hadoop.merge.MergeComparator.java

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/*******************************************************************************
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use these files 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.
 *
 * Copyright 2014 - Juan Pino, Aurelien Waite, William Byrne
 *******************************************************************************/
package uk.ac.cam.eng.extraction.hadoop.merge;

import java.io.IOException;

import org.apache.hadoop.io.DataOutputBuffer;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;

import uk.ac.cam.eng.extraction.hadoop.datatypes.RuleWritable;

/**
 * Need a byte level comparator for rule writable. Otherwise we are unable to
 * add it to the HFILE
 * 
 * @author Aurelien Waite
 * @date 28 May 2014
 */
public class MergeComparator extends WritableComparator {

    private final DataOutputBuffer buffera = new DataOutputBuffer();
    private final DataOutputBuffer bufferb = new DataOutputBuffer();

    public MergeComparator() {
        super(RuleWritable.class);
    }

    @Override
    @SuppressWarnings("rawtypes")
    public int compare(WritableComparable a, WritableComparable b) {
        try {
            buffera.reset();
            a.write(buffera);
            bufferb.reset();
            b.write(bufferb);
            return compareBytes(buffera.getData(), 0, buffera.getLength(), bufferb.getData(), 0,
                    bufferb.getLength());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
        return compareBytes(b1, s1, l1, b2, s2, l2);
    }

}