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
019package org.apache.hadoop.mapreduce;
020
021import java.io.IOException;
022
023import org.apache.hadoop.classification.InterfaceAudience;
024import org.apache.hadoop.classification.InterfaceStability;
025import org.apache.hadoop.fs.FileSystem;
026
027/**
028 * <code>RecordWriter</code> writes the output &lt;key, value&gt; pairs 
029 * to an output file.
030 
031 * <p><code>RecordWriter</code> implementations write the job outputs to the
032 * {@link FileSystem}.
033 * 
034 * @see OutputFormat
035 */
036@InterfaceAudience.Public
037@InterfaceStability.Stable
038public abstract class RecordWriter<K, V> {
039  /** 
040   * Writes a key/value pair.
041   *
042   * @param key the key to write.
043   * @param value the value to write.
044   * @throws IOException
045   */      
046  public abstract void write(K key, V value
047                             ) throws IOException, InterruptedException;
048
049  /** 
050   * Close this <code>RecordWriter</code> to future operations.
051   * 
052   * @param context the context of the task
053   * @throws IOException
054   */ 
055  public abstract void close(TaskAttemptContext context
056                             ) throws IOException, InterruptedException;
057}