/**
*
* 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.mapreduce;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapreduce.Reducer;
/**
* Extends the basic <code>Reducer</code> class to add the required key and
* value input/output classes. While the input key and value as well as the
* output key can be anything handed in from the previous map phase the output
* value <u>must</u> be either a {@link org.apache.hadoop.hbase.client.Put Put}
* or a {@link org.apache.hadoop.hbase.client.Delete Delete} instance when
* using the {@link TableOutputFormat} class.
* <p>
* This class is extended by {@link IdentityTableReducer} but can also be
* subclassed to implement similar features or any custom code needed. It has
* the advantage to enforce the output value to a specific basic type.
*
* @param <KEYIN> The type of the input key.
* @param <VALUEIN> The type of the input value.
* @param <KEYOUT> The type of the output key.
* @see org.apache.hadoop.mapreduce.Reducer
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class TableReducer<KEYIN, VALUEIN, KEYOUT>
extends Reducer<KEYIN, VALUEIN, KEYOUT, Writable> {
}