/**
* 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.hadoop.mapreduce.task;
import java.io.IOException;
import java.net.URI;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configuration.IntegerRanges;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.RawComparator;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.JobID;
import org.apache.hadoop.mapreduce.MRJobConfig;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.mapreduce.Partitioner;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.filecache.DistributedCache;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.mapreduce.lib.partition.HashPartitioner;
import org.apache.hadoop.security.Credentials;
import org.apache.hadoop.security.UserGroupInformation;
/**
* A read-only view of the job that is provided to the tasks while they
* are running.
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class JobContextImpl implements JobContext {
protected final org.apache.hadoop.mapred.JobConf conf;
private JobID jobId;
/**
* The UserGroupInformation object that has a reference to the current user
*/
protected UserGroupInformation ugi;
protected final Credentials credentials;
public JobContextImpl(Configuration conf, JobID jobId) {
if (conf instanceof JobConf) {
this.conf = (JobConf)conf;
} else {
this.conf = new JobConf(conf);
}
this.jobId = jobId;
this.credentials = this.conf.getCredentials();
try {
this.ugi = UserGroupInformation.getCurrentUser();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* Return the configuration for the job.
* @return the shared configuration object
*/
public Configuration getConfiguration() {
return conf;
}
/**
* Get the unique ID for the job.
* @return the object with the job id
*/
public JobID getJobID() {
return jobId;
}
/**
* Set the JobID.
*/
public void setJobID(JobID jobId) {
this.jobId = jobId;
}
/**
* Get configured the number of reduce tasks for this job. Defaults to
* <code>1</code>.
* @return the number of reduce tasks for this job.
*/
public int getNumReduceTasks() {
return conf.getNumReduceTasks();
}
/**
* Get the current working directory for the default file system.
*
* @return the directory name.
*/
public Path getWorkingDirectory() throws IOException {
return conf.getWorkingDirectory();
}
/**
* Get the key class for the job output data.
* @return the key class for the job output data.
*/
public Class<?> getOutputKeyClass() {
return conf.getOutputKeyClass();
}
/**
* Get the value class for job outputs.
* @return the value class for job outputs.
*/
public Class<?> getOutputValueClass() {
return conf.getOutputValueClass();
}
/**
* Get the key class for the map output data. If it is not set, use the
* (final) output key class. This allows the map output key class to be
* different than the final output key class.
* @return the map output key class.
*/
public Class<?> getMapOutputKeyClass() {
return conf.getMapOutputKeyClass();
}
/**
* Get the value class for the map output data. If it is not set, use the
* (final) output value class This allows the map output value class to be
* different than the final output value class.
*
* @return the map output value class.
*/
public Class<?> getMapOutputValueClass() {
return conf.getMapOutputValueClass();
}
/**
* Get the user-specified job name. This is only used to identify the
* job to the user.
*
* @return the job's name, defaulting to "".
*/
public String getJobName() {
return conf.getJobName();
}
/**
* Get the {@link InputFormat} class for the job.
*
* @return the {@link InputFormat} class for the job.
*/
@SuppressWarnings("unchecked")
public Class<? extends InputFormat<?,?>> getInputFormatClass()
throws ClassNotFoundException {
return (Class<? extends InputFormat<?,?>>)
conf.getClass(INPUT_FORMAT_CLASS_ATTR, TextInputFormat.class);
}
/**
* Get the {@link Mapper} class for the job.
*
* @return the {@link Mapper} class for the job.
*/
@SuppressWarnings("unchecked")
public Class<? extends Mapper<?,?,?,?>> getMapperClass()
throws ClassNotFoundException {
return (Class<? extends Mapper<?,?,?,?>>)
conf.getClass(MAP_CLASS_ATTR, Mapper.class);
}
/**
* Get the combiner class for the job.
*
* @return the combiner class for the job.
*/
@SuppressWarnings("unchecked")
public Class<? extends Reducer<?,?,?,?>> getCombinerClass()
throws ClassNotFoundException {
return (Class<? extends Reducer<?,?,?,?>>)
conf.getClass(COMBINE_CLASS_ATTR, null);
}
/**
* Get the {@link Reducer} class for the job.
*
* @return the {@link Reducer} class for the job.
*/
@SuppressWarnings("unchecked")
public Class<? extends Reducer<?,?,?,?>> getReducerClass()
throws ClassNotFoundException {
return (Class<? extends Reducer<?,?,?,?>>)
conf.getClass(REDUCE_CLASS_ATTR, Reducer.class);
}
/**
* Get the {@link OutputFormat} class for the job.
*
* @return the {@link OutputFormat} class for the job.
*/
@SuppressWarnings("unchecked")
public Class<? extends OutputFormat<?,?>> getOutputFormatClass()
throws ClassNotFoundException {
return (Class<? extends OutputFormat<?,?>>)
conf.getClass(OUTPUT_FORMAT_CLASS_ATTR, TextOutputFormat.class);
}
/**
* Get the {@link Partitioner} class for the job.
*
* @return the {@link Partitioner} class for the job.
*/
@SuppressWarnings("unchecked")
public Class<? extends Partitioner<?,?>> getPartitionerClass()
throws ClassNotFoundException {
return (Class<? extends Partitioner<?,?>>)
conf.getClass(PARTITIONER_CLASS_ATTR, HashPartitioner.class);
}
/**
* Get the {@link RawComparator} comparator used to compare keys.
*
* @return the {@link RawComparator} comparator used to compare keys.
*/
public RawComparator<?> getSortComparator() {
return conf.getOutputKeyComparator();
}
/**
* Get the pathname of the job's jar.
* @return the pathname
*/
public String getJar() {
return conf.getJar();
}
/**
* Get the user defined {@link RawComparator} comparator for
* grouping keys of inputs to the reduce.
*
* @return comparator set by the user for grouping values.
* @see Job#setGroupingComparatorClass(Class) for details.
*/
public RawComparator<?> getGroupingComparator() {
return conf.getOutputValueGroupingComparator();
}
/**
* Get whether job-setup and job-cleanup is needed for the job
*
* @return boolean
*/
public boolean getJobSetupCleanupNeeded() {
return conf.getBoolean(MRJobConfig.SETUP_CLEANUP_NEEDED, true);
}
/**
* Get whether task-cleanup is needed for the job
*
* @return boolean
*/
public boolean getTaskCleanupNeeded() {
return conf.getBoolean(MRJobConfig.TASK_CLEANUP_NEEDED, true);
}
/**
* This method checks to see if symlinks are to be create for the
* localized cache files in the current working directory
* @return true if symlinks are to be created- else return false
*/
public boolean getSymlink() {
return DistributedCache.getSymlink(conf);
}
/**
* Get the archive entries in classpath as an array of Path
*/
public Path[] getArchiveClassPaths() {
return DistributedCache.getArchiveClassPaths(conf);
}
/**
* Get cache archives set in the Configuration
* @return A URI array of the caches set in the Configuration
* @throws IOException
*/
public URI[] getCacheArchives() throws IOException {
return DistributedCache.getCacheArchives(conf);
}
/**
* Get cache files set in the Configuration
* @return A URI array of the files set in the Configuration
* @throws IOException
*/
public URI[] getCacheFiles() throws IOException {
return DistributedCache.getCacheFiles(conf);
}
/**
* Return the path array of the localized caches
* @return A path array of localized caches
* @throws IOException
*/
public Path[] getLocalCacheArchives()
throws IOException {
return DistributedCache.getLocalCacheArchives(conf);
}
/**
* Return the path array of the localized files
* @return A path array of localized files
* @throws IOException
*/
public Path[] getLocalCacheFiles()
throws IOException {
return DistributedCache.getLocalCacheFiles(conf);
}
/**
* Get the file entries in classpath as an array of Path
*/
public Path[] getFileClassPaths() {
return DistributedCache.getFileClassPaths(conf);
}
/**
* Get the timestamps of the archives. Used by internal
* DistributedCache and MapReduce code.
* @return a string array of timestamps
* @throws IOException
*/
public String[] getArchiveTimestamps() {
return DistributedCache.getArchiveTimestamps(conf);
}
/**
* Get the timestamps of the files. Used by internal
* DistributedCache and MapReduce code.
* @return a string array of timestamps
* @throws IOException
*/
public String[] getFileTimestamps() {
return DistributedCache.getFileTimestamps(conf);
}
/**
* Get the configured number of maximum attempts that will be made to run a
* map task, as specified by the <code>mapred.map.max.attempts</code>
* property. If this property is not already set, the default is 4 attempts.
*
* @return the max number of attempts per map task.
*/
public int getMaxMapAttempts() {
return conf.getMaxMapAttempts();
}
/**
* Get the configured number of maximum attempts that will be made to run a
* reduce task, as specified by the <code>mapred.reduce.max.attempts</code>
* property. If this property is not already set, the default is 4 attempts.
*
* @return the max number of attempts per reduce task.
*/
public int getMaxReduceAttempts() {
return conf.getMaxReduceAttempts();
}
/**
* Get whether the task profiling is enabled.
* @return true if some tasks will be profiled
*/
public boolean getProfileEnabled() {
return conf.getProfileEnabled();
}
/**
* Get the profiler configuration arguments.
*
* The default value for this property is
* "-agentlib:hprof=cpu=samples,heap=sites,force=n,thread=y,verbose=n,file=%s"
*
* @return the parameters to pass to the task child to configure profiling
*/
public String getProfileParams() {
return conf.getProfileParams();
}
/**
* Get the range of maps or reduces to profile.
* @param isMap is the task a map?
* @return the task ranges
*/
public IntegerRanges getProfileTaskRange(boolean isMap) {
return conf.getProfileTaskRange(isMap);
}
/**
* Get the reported username for this job.
*
* @return the username
*/
public String getUser() {
return conf.getUser();
}
public Credentials getCredentials() {
return credentials;
}
}