HadoopCompat (apache-cassandra API)
Date: 2018-02-14

org.apache.cassandra.hadoop

## Class HadoopCompat

- java.lang.Object
- - org.apache.cassandra.hadoop.HadoopCompat

-     public class HadoopCompat
      extends java.lang.Object

  Utility methods to allow applications to deal with inconsistencies between MapReduce Context Objects API between Hadoop 1.x and 2.x.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `HadoopCompat()`

  - ### Method Summary

    All Methods Static Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static org.apache.hadoop.conf.Configuration` | `getConfiguration(org.apache.hadoop.mapreduce.JobContext context)` Invoke getConfiguration() on JobContext.
    `static org.apache.hadoop.mapreduce.Counter` | `getCounter(org.apache.hadoop.mapreduce.TaskInputOutputContext context, java.lang.String groupName, java.lang.String counterName)` Invoke getCounter() on TaskInputOutputContext.
    `static org.apache.hadoop.mapreduce.TaskAttemptID` | `getTaskAttemptID(org.apache.hadoop.mapreduce.TaskAttemptContext taskContext)` returns TaskAttemptContext.getTaskAttemptID().
    `static void` | `incrementCounter(org.apache.hadoop.mapreduce.Counter counter, long increment)` Increment the counter.
    `static boolean` | `isVersion2x()` True if runtime Hadoop version is 2.x, false otherwise.
    `static org.apache.hadoop.mapreduce.Counter` | `newGenericCounter(java.lang.String name, java.lang.String displayName, long value)`
    `static org.apache.hadoop.mapreduce.JobContext` | `newJobContext(org.apache.hadoop.conf.Configuration conf, org.apache.hadoop.mapreduce.JobID jobId)` Creates JobContext from a JobConf and jobId using the correct constructor for based on Hadoop version.
    `static org.apache.hadoop.mapreduce.MapContext` | `newMapContext(org.apache.hadoop.conf.Configuration conf, org.apache.hadoop.mapreduce.TaskAttemptID taskAttemptID, org.apache.hadoop.mapreduce.RecordReader recordReader, org.apache.hadoop.mapreduce.RecordWriter recordWriter, org.apache.hadoop.mapreduce.OutputCommitter outputCommitter, org.apache.hadoop.mapreduce.StatusReporter statusReporter, org.apache.hadoop.mapreduce.InputSplit inputSplit)` Instantiates MapContext under Hadoop 1 and MapContextImpl under Hadoop 2.
    `static org.apache.hadoop.mapreduce.TaskAttemptContext` | `newTaskAttemptContext(org.apache.hadoop.conf.Configuration conf, org.apache.hadoop.mapreduce.TaskAttemptID taskAttemptId)` Creates TaskAttempContext from a JobConf and jobId using the correct constructor for based on Hadoop version.
    `static void` | `progress(org.apache.hadoop.mapreduce.TaskAttemptContext context)` Invoke TaskAttemptContext.progress().
    `static void` | `setStatus(org.apache.hadoop.mapreduce.TaskAttemptContext context, java.lang.String status)` Invoke setStatus() on TaskAttemptContext.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### HadoopCompat

          public HadoopCompat()

  - ### Method Detail

    - #### isVersion2x

          public static boolean isVersion2x()

      True if runtime Hadoop version is 2.x, false otherwise.

    - #### newJobContext

          public static org.apache.hadoop.mapreduce.JobContext newJobContext(org.apache.hadoop.conf.Configuration conf,
                                                                             org.apache.hadoop.mapreduce.JobID jobId)

      Creates JobContext from a JobConf and jobId using the correct constructor for based on Hadoop version. `jobId` could be null.

    - #### newTaskAttemptContext

          public static org.apache.hadoop.mapreduce.TaskAttemptContext newTaskAttemptContext(org.apache.hadoop.conf.Configuration conf,
                                                                                             org.apache.hadoop.mapreduce.TaskAttemptID taskAttemptId)

      Creates TaskAttempContext from a JobConf and jobId using the correct constructor for based on Hadoop version.

    - #### newMapContext

          public static org.apache.hadoop.mapreduce.MapContext newMapContext(org.apache.hadoop.conf.Configuration conf,
                                                                             org.apache.hadoop.mapreduce.TaskAttemptID taskAttemptID,
                                                                             org.apache.hadoop.mapreduce.RecordReader recordReader,
                                                                             org.apache.hadoop.mapreduce.RecordWriter recordWriter,
                                                                             org.apache.hadoop.mapreduce.OutputCommitter outputCommitter,
                                                                             org.apache.hadoop.mapreduce.StatusReporter statusReporter,
                                                                             org.apache.hadoop.mapreduce.InputSplit inputSplit)

      Instantiates MapContext under Hadoop 1 and MapContextImpl under Hadoop 2.

    - #### newGenericCounter

          public static org.apache.hadoop.mapreduce.Counter newGenericCounter(java.lang.String name,
                                                                              java.lang.String displayName,
                                                                              long value)

      Returns:
        with Hadoop 2 : `new GenericCounter(args)`,
        with Hadoop 1 : `new Counter(args)`

    - #### getConfiguration

          public static org.apache.hadoop.conf.Configuration getConfiguration(org.apache.hadoop.mapreduce.JobContext context)

      Invoke getConfiguration() on JobContext. Works with both Hadoop 1 and 2.

    - #### setStatus

          public static void setStatus(org.apache.hadoop.mapreduce.TaskAttemptContext context,
                                       java.lang.String status)

      Invoke setStatus() on TaskAttemptContext. Works with both Hadoop 1 and 2.

    - #### getTaskAttemptID

          public static org.apache.hadoop.mapreduce.TaskAttemptID getTaskAttemptID(org.apache.hadoop.mapreduce.TaskAttemptContext taskContext)

      returns TaskAttemptContext.getTaskAttemptID(). Works with both Hadoop 1 and 2.

    - #### getCounter

          public static org.apache.hadoop.mapreduce.Counter getCounter(org.apache.hadoop.mapreduce.TaskInputOutputContext context,
                                                                       java.lang.String groupName,
                                                                       java.lang.String counterName)

      Invoke getCounter() on TaskInputOutputContext. Works with both Hadoop 1 and 2.

    - #### progress

          public static void progress(org.apache.hadoop.mapreduce.TaskAttemptContext context)

      Invoke TaskAttemptContext.progress(). Works with both Hadoop 1 and 2.

    - #### incrementCounter

          public static void incrementCounter(org.apache.hadoop.mapreduce.Counter counter,
                                              long increment)

      Increment the counter. Works with both Hadoop 1 and 2

Copyright © 2018 The Apache Software Foundation