SimpleIndexKeyGenerator.java

/**
 * Copyright 2009 The Apache Software Foundation
 *
 * 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.hadoop.hbase.client.tableindexed;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Map;

import org.apache.hadoop.hbase.util.Bytes;

/** Creates indexed keys for a single column....
 * 
 */
public class SimpleIndexKeyGenerator implements IndexKeyGenerator {

  private byte [] column;
  
  public SimpleIndexKeyGenerator(byte [] column) {
    this.column = column;
  }
  
  public SimpleIndexKeyGenerator() {
    // For Writable
  }
  
  /** {@inheritDoc} */
  public byte[] createIndexKey(byte[] rowKey, Map<byte[], byte[]> columns) {
    return Bytes.add(columns.get(column), rowKey);
  }

  /** {@inheritDoc} */
  public void readFields(DataInput in) throws IOException {
    column = Bytes.readByteArray(in);
  }

  /** {@inheritDoc} */
  public void write(DataOutput out) throws IOException {
    Bytes.writeByteArray(out, column);
  }

}