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 import java.util.HashSet; 023 import java.util.Set; 024 025 import org.apache.hadoop.classification.InterfaceAudience; 026 import org.apache.hadoop.classification.InterfaceStability; 027 import org.apache.hadoop.fs.BlockLocation; 028 import org.apache.hadoop.fs.FileStatus; 029 import org.apache.hadoop.fs.FileSystem; 030 import org.apache.hadoop.fs.Path; 031 import org.apache.hadoop.mapred.lib.CombineFileSplit; 032 033 /** 034 * A sub-collection of input files. Unlike {@link FileSplit}, MultiFileSplit 035 * class does not represent a split of a file, but a split of input files 036 * into smaller sets. The atomic unit of split is a file. <br> 037 * MultiFileSplit can be used to implement {@link RecordReader}'s, with 038 * reading one record per file. 039 * @see FileSplit 040 * @see MultiFileInputFormat 041 */ 042 @InterfaceAudience.Public 043 @InterfaceStability.Stable 044 public class MultiFileSplit extends CombineFileSplit { 045 046 MultiFileSplit() {} 047 048 public MultiFileSplit(JobConf job, Path[] files, long[] lengths) { 049 super(job, files, lengths); 050 } 051 052 public String[] getLocations() throws IOException { 053 HashSet<String> hostSet = new HashSet<String>(); 054 for (Path file : getPaths()) { 055 FileSystem fs = file.getFileSystem(getJob()); 056 FileStatus status = fs.getFileStatus(file); 057 BlockLocation[] blkLocations = fs.getFileBlockLocations(status, 058 0, status.getLen()); 059 if (blkLocations != null && blkLocations.length > 0) { 060 addToSet(hostSet, blkLocations[0].getHosts()); 061 } 062 } 063 return hostSet.toArray(new String[hostSet.size()]); 064 } 065 066 private void addToSet(Set<String> set, String[] array) { 067 for(String s:array) 068 set.add(s); 069 } 070 071 @Override 072 public String toString() { 073 StringBuffer sb = new StringBuffer(); 074 for(int i=0; i < getPaths().length; i++) { 075 sb.append(getPath(i).toUri().getPath() + ":0+" + getLength(i)); 076 if (i < getPaths().length -1) { 077 sb.append("\n"); 078 } 079 } 080 081 return sb.toString(); 082 } 083 } 084