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; 025 026 /** 027 * Expert: Generic interface for {@link Mapper}s. 028 * 029 * <p>Custom implementations of <code>MapRunnable</code> can exert greater 030 * control on map processing e.g. multi-threaded, asynchronous mappers etc.</p> 031 * 032 * @see Mapper 033 * @deprecated Use {@link org.apache.hadoop.mapreduce.Mapper} instead. 034 */ 035 @Deprecated 036 @InterfaceAudience.Public 037 @InterfaceStability.Stable 038 public interface MapRunnable<K1, V1, K2, V2> 039 extends JobConfigurable { 040 041 /** 042 * Start mapping input <tt><key, value></tt> pairs. 043 * 044 * <p>Mapping of input records to output records is complete when this method 045 * returns.</p> 046 * 047 * @param input the {@link RecordReader} to read the input records. 048 * @param output the {@link OutputCollector} to collect the outputrecords. 049 * @param reporter {@link Reporter} to report progress, status-updates etc. 050 * @throws IOException 051 */ 052 void run(RecordReader<K1, V1> input, OutputCollector<K2, V2> output, 053 Reporter reporter) 054 throws IOException; 055 }