/** * Copyright 2005 The Apache Software Foundation * * Licensed 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.mapred;import org.apache.hadoop.conf.*;import java.io.*;/** Runs a map task. */class MapTaskRunner extends TaskRunner {  private MapOutputFile mapOutputFile;  public MapTaskRunner(Task task, TaskTracker tracker, Configuration conf) {    super(task, tracker, conf);    this.mapOutputFile = new MapOutputFile();    this.mapOutputFile.setConf(conf);  }    /** Delete any temporary files from previous failed attempts. */  public boolean prepare() throws IOException {    this.mapOutputFile.removeAll(getTask().getTaskId());    return true;  }  /** Delete all of the temporary map output files. */  public void close() throws IOException {    LOG.info(getTask()+" done; removing files.");    this.mapOutputFile.removeAll(getTask().getTaskId());  }}