Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.tez.runtime.library.common.task.local.output; import java.io.IOException; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.classification.InterfaceStability; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.LocalDirAllocator; import org.apache.hadoop.fs.Path; import org.apache.tez.common.TezRuntimeFrameworkConfigs; import org.apache.tez.runtime.library.common.Constants; import org.apache.tez.runtime.library.common.InputAttemptIdentifier; /** * Manipulate the working area for the transient store for maps and reduces. * * This class is used by map and reduce tasks to identify the directories that * they need to write to/read from for intermediate files. The callers of * these methods are from the Child running the Task. */ @InterfaceAudience.Private @InterfaceStability.Unstable public class TezLocalTaskOutputFiles extends TezTaskOutput { public TezLocalTaskOutputFiles(Configuration conf, String uniqueId) { super(conf, uniqueId); } private LocalDirAllocator lDirAlloc = new LocalDirAllocator(TezRuntimeFrameworkConfigs.LOCAL_DIRS); /** * Return the path to local map output file created earlier * * @return path * @throws IOException */ @Override public Path getOutputFile() throws IOException { return lDirAlloc.getLocalPathToRead(Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + Path.SEPARATOR + Constants.TEZ_RUNTIME_TASK_OUTPUT_FILENAME_STRING, conf); } /** * Create a local map output file name. * * @param size the size of the file * @return path * @throws IOException */ @Override public Path getOutputFileForWrite(long size) throws IOException { return lDirAlloc.getLocalPathForWrite(Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + Path.SEPARATOR + Constants.TEZ_RUNTIME_TASK_OUTPUT_FILENAME_STRING, size, conf); } /** * Create a local map output file name. This should *only* be used if the size * of the file is not known. Otherwise use the equivalent which accepts a size * parameter. * * @return path * @throws IOException */ @Override public Path getOutputFileForWrite() throws IOException { return lDirAlloc.getLocalPathForWrite(Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + Path.SEPARATOR + Constants.TEZ_RUNTIME_TASK_OUTPUT_FILENAME_STRING, conf); } /** * Create a local map output file name on the same volume. */ @Override public Path getOutputFileForWriteInVolume(Path existing) { return new Path(existing.getParent(), Constants.TEZ_RUNTIME_TASK_OUTPUT_FILENAME_STRING); } /** * Return the path to a local map output index file created earlier * * @return path * @throws IOException */ @Override public Path getOutputIndexFile() throws IOException { return lDirAlloc.getLocalPathToRead(Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + Path.SEPARATOR + Constants.TEZ_RUNTIME_TASK_OUTPUT_FILENAME_STRING + Constants.TEZ_RUNTIME_TASK_OUTPUT_INDEX_SUFFIX_STRING, conf); } /** * Create a local map output index file name. * * @param size the size of the file * @return path * @throws IOException */ @Override public Path getOutputIndexFileForWrite(long size) throws IOException { return lDirAlloc.getLocalPathForWrite(Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + Path.SEPARATOR + Constants.TEZ_RUNTIME_TASK_OUTPUT_FILENAME_STRING + Constants.TEZ_RUNTIME_TASK_OUTPUT_INDEX_SUFFIX_STRING, size, conf); } /** * Create a local map output index file name on the same volume. */ @Override public Path getOutputIndexFileForWriteInVolume(Path existing) { return new Path(existing.getParent(), Constants.TEZ_RUNTIME_TASK_OUTPUT_FILENAME_STRING + Constants.TEZ_RUNTIME_TASK_OUTPUT_INDEX_SUFFIX_STRING); } /** * Return a local map spill file created earlier. * * @param spillNumber the number * @return path * @throws IOException */ @Override public Path getSpillFile(int spillNumber) throws IOException { return lDirAlloc.getLocalPathToRead(Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + "/spill" + spillNumber + ".out", conf); } /** * Create a local map spill file name. * * @param spillNumber the number * @param size the size of the file * @return path * @throws IOException */ @Override public Path getSpillFileForWrite(int spillNumber, long size) throws IOException { return lDirAlloc.getLocalPathForWrite( Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + "/spill" + spillNumber + ".out", size, conf); } /** * Return a local map spill index file created earlier * * @param spillNumber the number * @return path * @throws IOException */ @Override public Path getSpillIndexFile(int spillNumber) throws IOException { return lDirAlloc.getLocalPathToRead( Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + "/spill" + spillNumber + ".out.index", conf); } /** * Create a local map spill index file name. * * @param spillNumber the number * @param size the size of the file * @return path * @throws IOException */ @Override public Path getSpillIndexFileForWrite(int spillNumber, long size) throws IOException { return lDirAlloc.getLocalPathForWrite( Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR + "/spill" + spillNumber + ".out.index", size, conf); } /** * Return a local reduce input file created earlier * * @param mapId a map task id * @return path * @throws IOException */ @Override public Path getInputFile(InputAttemptIdentifier mapId) throws IOException { return lDirAlloc.getLocalPathToRead(String.format(Constants.TEZ_RUNTIME_TASK_INPUT_FILE_FORMAT_STRING, Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR, Integer.valueOf(mapId.getInputIdentifier().getInputIndex())), conf); } /** * Create a local reduce input file name. * * @param taskId a task id * @param size the size of the file * @return path * @throws IOException */ @Override public Path getInputFileForWrite(int taskId, long size) throws IOException { return lDirAlloc.getLocalPathForWrite(getSpillFileName(taskId), size, conf); } @Override public String getSpillFileName(int spillNum) { return (String.format(Constants.TEZ_RUNTIME_TASK_INPUT_FILE_FORMAT_STRING, Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR, spillNum)); } /** Removes all of the files related to a task. */ @Override public void removeAll() throws IOException { deleteLocalFiles(Constants.TEZ_RUNTIME_TASK_OUTPUT_DIR); } private String[] getLocalDirs() throws IOException { return conf.getStrings(TezRuntimeFrameworkConfigs.LOCAL_DIRS); } @SuppressWarnings("deprecation") private void deleteLocalFiles(String subdir) throws IOException { String[] localDirs = getLocalDirs(); for (int i = 0; i < localDirs.length; i++) { FileSystem.getLocal(conf).delete(new Path(localDirs[i], subdir)); } } }