/**
* Copyright [2012] [Datasalt Systems S.L.]
*
* Licensed 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 com.datasalt.pangool.tuplemr.mapred;
import java.io.IOException;
import java.io.Serializable;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.DataOutputBuffer;
import org.apache.hadoop.io.RawComparator;
import org.apache.hadoop.io.WritableComparator;
import com.datasalt.pangool.serialization.HadoopSerialization;
/**
* A simple {@link RawComparator} and {@link Serializable} that
* compares in binary. It also implements Comparator<Object>{@link #compare(Object, Object)}
* by serializing the objects using {@link HadoopSerialization},
* and then comparing the bytes. That is useful for testing purposes.
* <br>
* This class needs to receive a configuration via {@link #setConf(Configuration)} before
* being ready to use the {@link #compare(Object, Object)} method.
*/
@SuppressWarnings("serial")
public class BinaryComparator implements RawComparator<Object>, Serializable, Configurable {
protected Configuration conf;
protected HadoopSerialization ser;
private DataOutputBuffer buf1;
private DataOutputBuffer buf2;
@Override
public int compare(Object o1, Object o2) {
try {
if (o1 == null) {
return (o2 == null) ? 0 : -1;
} else if (o2 == null) {
return 1;
}
buf1.reset();
ser.ser(o1, buf1);
buf2.reset();
ser.ser(o2, buf2);
return compare(buf1.getData(), 0, buf1.getLength(), buf2.getData(), 0, buf2.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 WritableComparator.compareBytes(b1, s1, l1, b2, s2, l2);
}
@Override
public void setConf(Configuration conf) {
buf1 = new DataOutputBuffer();
buf2 = new DataOutputBuffer();
try {
ser = new HadoopSerialization(conf);
} catch(IOException e) {
throw new RuntimeException(e);
}
}
@Override
public Configuration getConf() {
return conf;
}
}