IdDatum.java

/**
 * Copyright [2011] [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.utils.io;

import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.WritableComparator;

/**
 * A class with a number, that can be used as an identifier of the types
 * of the data that the other item, stored as byte array, belongs to. These arrays can be
 * objects serialized with the {@link Serialization}.
 * <br/>
 * The advantages of this class is that the comparison is done at the binary level,
 * without deserializing the item. That can be useful for using this class as key 
 * on a Map Reduce job.
 * <br/>
 * Item must be present and cannot be null. 
 *
 * @author ivan,eric
 *
 */
public class IdDatum extends IdDatumBase {

  static {                                        // register this comparator
    WritableComparator.define(IdDatum.class, new Comparator());
  }

	@Override
  public int getIdentifier() {
	  return super.getIdentifier();
  }

	@Override
  public void setIdentifier(int identifier) {
	  super.setIdentifier(identifier);
  }

	@Override
  public BytesWritable getItem1() {
	  return super.getItem1();
  }

	@Override
  public void setItem1(byte[] datum, int offset, int length) {
	  super.setItem1(datum, offset, length);
  }

	@Override
  public void setItem1(BytesWritable writable) {
	  super.setItem1(writable);
  }

	@Override
  public void setItem1(byte[] datum) {
	  super.setItem1(datum);
  }
}