JobContext (Hadoop 1.2.2-SNAPSHOT API)

java.lang.Object
- org.apache.hadoop.mapreduce.JobContext

直接已知子类:

Job, JobContext, TaskAttemptContext
```
public class JobContext
extends Object
```
A read-only view of the job that is provided to the tasks while they are running.

字段概要

字段
限定符和类型	字段和说明
`static String`	`CACHE_ARCHIVES_VISIBILITIES`
`static String`	`CACHE_FILE_VISIBILITIES`
`protected static String`	`COMBINE_CLASS_ATTR`
`protected JobConf`	`conf`
`protected Credentials`	`credentials`
`protected static String`	`INPUT_FORMAT_CLASS_ATTR`
`static String`	`JOB_ACL_MODIFY_JOB`
`static String`	`JOB_ACL_VIEW_JOB`
`static String`	`JOB_CANCEL_DELEGATION_TOKEN`
`static String`	`JOB_NAMENODES`
`protected static String`	`MAP_CLASS_ATTR`
`protected static String`	`OUTPUT_FORMAT_CLASS_ATTR`
`protected static String`	`PARTITIONER_CLASS_ATTR`
`protected static String`	`REDUCE_CLASS_ATTR`
`protected UserGroupInformation`	`ugi` The UserGroupInformation object that has a reference to the current user
`static String`	`USER_LOG_RETAIN_HOURS`

构造器概要

构造器
构造器和说明

JobContext(Configuration conf, JobID jobId)

构造器
构造器和说明
`JobContext(Configuration conf, JobID jobId)`

方法概要

方法
限定符和类型	方法和说明
`Class<? extends Reducer<?,?,?,?>>`	`getCombinerClass()` Get the combiner class for the job.
`Configuration`	`getConfiguration()` Return the configuration for the job.
`Credentials`	`getCredentials()` Get credentials for the job.
`RawComparator<?>`	`getGroupingComparator()` Get the user defined `RawComparator` comparator for grouping keys of inputs to the reduce.
`Class<? extends InputFormat<?,?>>`	`getInputFormatClass()` Get the `InputFormat` class for the job.
`String`	`getJar()` Get the pathname of the job's jar.
`JobID`	`getJobID()` Get the unique ID for the job.
`String`	`getJobName()` Get the user-specified job name.
`Class<?>`	`getMapOutputKeyClass()` Get the key class for the map output data.
`Class<?>`	`getMapOutputValueClass()` Get the value class for the map output data.
`Class<? extends Mapper<?,?,?,?>>`	`getMapperClass()` Get the `Mapper` class for the job.
`int`	`getNumReduceTasks()` Get configured the number of reduce tasks for this job.
`Class<? extends OutputFormat<?,?>>`	`getOutputFormatClass()` Get the `OutputFormat` class for the job.
`Class<?>`	`getOutputKeyClass()` Get the key class for the job output data.
`Class<?>`	`getOutputValueClass()` Get the value class for job outputs.
`Class<? extends Partitioner<?,?>>`	`getPartitionerClass()` Get the `Partitioner` class for the job.
`Class<? extends Reducer<?,?,?,?>>`	`getReducerClass()` Get the `Reducer` class for the job.
`RawComparator<?>`	`getSortComparator()` Get the `RawComparator` comparator used to compare keys.
`Path`	`getWorkingDirectory()` Get the current working directory for the default file system.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 字段详细资料
  - INPUT_FORMAT_CLASS_ATTR
```
protected static final String INPUT_FORMAT_CLASS_ATTR
```
    另请参阅:
    常量字段值
  - MAP_CLASS_ATTR
```
protected static final String MAP_CLASS_ATTR
```
    另请参阅:
    常量字段值
  - COMBINE_CLASS_ATTR
```
protected static final String COMBINE_CLASS_ATTR
```
    另请参阅:
    常量字段值
  - REDUCE_CLASS_ATTR
```
protected static final String REDUCE_CLASS_ATTR
```
    另请参阅:
    常量字段值
  - OUTPUT_FORMAT_CLASS_ATTR
```
protected static final String OUTPUT_FORMAT_CLASS_ATTR
```
    另请参阅:
    常量字段值
  - PARTITIONER_CLASS_ATTR
```
protected static final String PARTITIONER_CLASS_ATTR
```
    另请参阅:
    常量字段值
  - conf
```
protected final JobConf conf
```
  - credentials
```
protected final Credentials credentials
```
  - JOB_NAMENODES
```
public static final String JOB_NAMENODES
```
    另请参阅:
    常量字段值
  - JOB_ACL_VIEW_JOB
```
public static final String JOB_ACL_VIEW_JOB
```
    另请参阅:
    常量字段值
  - JOB_ACL_MODIFY_JOB
```
public static final String JOB_ACL_MODIFY_JOB
```
    另请参阅:
    常量字段值
  - CACHE_FILE_VISIBILITIES
```
public static final String CACHE_FILE_VISIBILITIES
```
    另请参阅:
    常量字段值
  - CACHE_ARCHIVES_VISIBILITIES
```
public static final String CACHE_ARCHIVES_VISIBILITIES
```
    另请参阅:
    常量字段值
  - JOB_CANCEL_DELEGATION_TOKEN
```
public static final String JOB_CANCEL_DELEGATION_TOKEN
```
    另请参阅:
    常量字段值
  - USER_LOG_RETAIN_HOURS
```
public static final String USER_LOG_RETAIN_HOURS
```
    另请参阅:
    常量字段值
  - ugi
```
protected UserGroupInformation ugi
```
    The UserGroupInformation object that has a reference to the current user
- 构造器详细资料
  - JobContext
```
public JobContext(Configuration conf,
          JobID jobId)
```
- 方法详细资料
  - getConfiguration
```
public Configuration getConfiguration()
```
    Return the configuration for the job.
    
    返回:
    the shared configuration object
  - getCredentials
```
public Credentials getCredentials()
```
    Get credentials for the job.
    
    返回:
    credentials for the job
  - getJobID
```
public JobID getJobID()
```
    Get the unique ID for the job.
    
    返回:
    the object with the job id
  - getNumReduceTasks
```
public int getNumReduceTasks()
```
    Get configured the number of reduce tasks for this job. Defaults to 1.
    
    返回:
    the number of reduce tasks for this job.
  - getWorkingDirectory
```
public Path getWorkingDirectory()
                         throws IOException
```
    Get the current working directory for the default file system.
    
    返回:
    the directory name.
    
    抛出:
    
    IOException
  - getOutputKeyClass
```
public Class<?> getOutputKeyClass()
```
    Get the key class for the job output data.
    
    返回:
    the key class for the job output data.
  - getOutputValueClass
```
public Class<?> getOutputValueClass()
```
    Get the value class for job outputs.
    
    返回:
    the value class for job outputs.
  - getMapOutputKeyClass
```
public Class<?> getMapOutputKeyClass()
```
    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.
    
    返回:
    the map output key class.
  - getMapOutputValueClass
```
public Class<?> getMapOutputValueClass()
```
    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.
    
    返回:
    the map output value class.
  - getJobName
```
public String getJobName()
```
    Get the user-specified job name. This is only used to identify the job to the user.
    
    返回:
    the job's name, defaulting to "".
  - getInputFormatClass
```
public Class<? extends InputFormat<?,?>> getInputFormatClass()
                                                      throws ClassNotFoundException
```
    Get the InputFormat class for the job.
    
    返回:
    the InputFormat class for the job.
    
    抛出:
    
    ClassNotFoundException
  - getMapperClass
```
public Class<? extends Mapper<?,?,?,?>> getMapperClass()
                                                throws ClassNotFoundException
```
    Get the Mapper class for the job.
    
    返回:
    the Mapper class for the job.
    
    抛出:
    
    ClassNotFoundException
  - getCombinerClass
```
public Class<? extends Reducer<?,?,?,?>> getCombinerClass()
                                                   throws ClassNotFoundException
```
    Get the combiner class for the job.
    
    返回:
    the combiner class for the job.
    
    抛出:
    
    ClassNotFoundException
  - getReducerClass
```
public Class<? extends Reducer<?,?,?,?>> getReducerClass()
                                                  throws ClassNotFoundException
```
    Get the Reducer class for the job.
    
    返回:
    the Reducer class for the job.
    
    抛出:
    
    ClassNotFoundException
  - getOutputFormatClass
```
public Class<? extends OutputFormat<?,?>> getOutputFormatClass()
                                                        throws ClassNotFoundException
```
    Get the OutputFormat class for the job.
    
    返回:
    the OutputFormat class for the job.
    
    抛出:
    
    ClassNotFoundException
  - getPartitionerClass
```
public Class<? extends Partitioner<?,?>> getPartitionerClass()
                                                      throws ClassNotFoundException
```
    Get the Partitioner class for the job.
    
    返回:
    the Partitioner class for the job.
    
    抛出:
    
    ClassNotFoundException
  - getSortComparator
```
public RawComparator<?> getSortComparator()
```
    Get the RawComparator comparator used to compare keys.
    
    返回:
    the RawComparator comparator used to compare keys.
  - getJar
```
public String getJar()
```
    Get the pathname of the job's jar.
    
    返回:
    the pathname
  - getGroupingComparator
```
public RawComparator<?> getGroupingComparator()
```
    Get the user defined RawComparator comparator for grouping keys of inputs to the reduce.
    
    返回:
    comparator set by the user for grouping values.
    另请参阅:
    for details.

类 JobContext

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

INPUT_FORMAT_CLASS_ATTR

MAP_CLASS_ATTR

COMBINE_CLASS_ATTR

REDUCE_CLASS_ATTR

OUTPUT_FORMAT_CLASS_ATTR

PARTITIONER_CLASS_ATTR

conf

credentials

JOB_NAMENODES

JOB_ACL_VIEW_JOB

JOB_ACL_MODIFY_JOB

CACHE_FILE_VISIBILITIES

CACHE_ARCHIVES_VISIBILITIES

JOB_CANCEL_DELEGATION_TOKEN

USER_LOG_RETAIN_HOURS

ugi

构造器详细资料

JobContext

方法详细资料

getConfiguration

getCredentials

getJobID

getNumReduceTasks

getWorkingDirectory

getOutputKeyClass

getOutputValueClass

getMapOutputKeyClass

getMapOutputValueClass

getJobName

getInputFormatClass

getMapperClass

getCombinerClass

getReducerClass

getOutputFormatClass

getPartitionerClass

getSortComparator

getJar

getGroupingComparator