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.hdfs; 020 021import java.io.IOException; 022import java.util.NoSuchElementException; 023 024import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks; 025import org.apache.hadoop.fs.Path; 026import org.apache.hadoop.fs.RemoteIterator; 027 028/** 029 * Provides an iterator interface for listCorruptFileBlocks. 030 * This class is used by DistributedFileSystem and Hdfs. 031 */ 032public class CorruptFileBlockIterator implements RemoteIterator<Path> { 033 private final DFSClient dfs; 034 private String path; 035 036 private String[] files = null; 037 private int fileIdx = 0; 038 private String cookie = null; 039 private Path nextPath = null; 040 041 private int callsMade = 0; 042 043 public CorruptFileBlockIterator(DFSClient dfs, Path path) throws IOException { 044 this.dfs = dfs; 045 this.path = path2String(path); 046 loadNext(); 047 } 048 049 /** 050 * @return the number of calls made to the DFSClient. 051 * This is for debugging and testing purposes. 052 */ 053 public int getCallsMade() { 054 return callsMade; 055 } 056 057 private String path2String(Path path) { 058 return path.toUri().getPath(); 059 } 060 061 private Path string2Path(String string) { 062 return new Path(string); 063 } 064 065 private void loadNext() throws IOException { 066 if (files == null || fileIdx >= files.length) { 067 CorruptFileBlocks cfb = dfs.listCorruptFileBlocks(path, cookie); 068 files = cfb.getFiles(); 069 cookie = cfb.getCookie(); 070 fileIdx = 0; 071 callsMade++; 072 } 073 074 if (fileIdx >= files.length) { 075 // received an empty response 076 // there are no more corrupt file blocks 077 nextPath = null; 078 } else { 079 nextPath = string2Path(files[fileIdx]); 080 fileIdx++; 081 } 082 } 083 084 085 @Override 086 public boolean hasNext() { 087 return nextPath != null; 088 } 089 090 091 @Override 092 public Path next() throws IOException { 093 if (!hasNext()) { 094 throw new NoSuchElementException("No more corrupt file blocks"); 095 } 096 097 Path result = nextPath; 098 loadNext(); 099 100 return result; 101 } 102}