001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package org.apache.hadoop.mapred;
020    
021    import java.io.IOException;
022    
023    import org.apache.hadoop.classification.InterfaceAudience;
024    import org.apache.hadoop.classification.InterfaceStability;
025    import org.apache.hadoop.io.Closeable;
026    
027    /** 
028     * Base class for {@link Mapper} and {@link Reducer} implementations.
029     * 
030     * <p>Provides default no-op implementations for a few methods, most non-trivial
031     * applications need to override some of them.</p>
032     */
033    @InterfaceAudience.Public
034    @InterfaceStability.Stable
035    public class MapReduceBase implements Closeable, JobConfigurable {
036    
037      /** Default implementation that does nothing. */
038      public void close() throws IOException {
039      }
040    
041      /** Default implementation that does nothing. */
042      public void configure(JobConf job) {
043      }
044    
045    }