CombineFileInputFormat (Hadoop 0.20.2-cdh3u3 API)
Date: 2012-03-20

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## org.apache.hadoop.mapred.lib
Class CombineFileInputFormat<K,V>

    java.lang.Object
      org.apache.hadoop.mapred.FileInputFormat<K,V>
          org.apache.hadoop.mapred.lib.CombineFileInputFormat<K,V>

All Implemented Interfaces:
  InputFormat<K,V>

    public abstract class CombineFileInputFormat<K,V>

extends FileInputFormat<K,V>

An abstract `InputFormat` that returns `CombineFileSplit`'s in `InputFormat.getSplits(JobConf, int)` method. Splits are constructed from the files under the input paths. A split cannot have files from different pools. Each split returned may contain blocks from different files. If a maxSplitSize is specified, then blocks on the same node are combined to form a single split. Blocks that are left over are then combined with other blocks in the same rack. If maxSplitSize is not specified, then blocks from the same rack are combined in a single split; no attempt is made to create node-local splits. If the maxSplitSize is equal to the block size, then this class is similar to the default spliting behaviour in Hadoop: each block is a locally processed split. Subclasses implement `InputFormat.getRecordReader(InputSplit, JobConf, Reporter)` to construct `RecordReader`'s for `CombineFileSplit`'s.

See Also:
  `CombineFileSplit`

Field Summary

Fields inherited from class org.apache.hadoop.mapred.FileInputFormat
`LOG`

Constructor Summary
`CombineFileInputFormat()` default constructor

Method Summary
`protected void` | `createPool(JobConf conf, List<PathFilter> filters)` Create a new pool and add the filters to it.
`protected void` | `createPool(JobConf conf, PathFilter... filters)` Create a new pool and add the filters to it.
`abstract RecordReader<K,V>` | `getRecordReader(InputSplit split, JobConf job, Reporter reporter)` This is not implemented yet.
`InputSplit[]` | `getSplits(JobConf job, int numSplits)` Splits files returned by `FileInputFormat.listStatus(JobConf)` when they're too big.
`protected void` | `setMaxSplitSize(long maxSplitSize)` Specify the maximum size (in bytes) of each split.
`protected void` | `setMinSplitSizeNode(long minSplitSizeNode)` Specify the minimum size (in bytes) of each split per node.
`protected void` | `setMinSplitSizeRack(long minSplitSizeRack)` Specify the minimum size (in bytes) of each split per rack.

Methods inherited from class org.apache.hadoop.mapred.FileInputFormat
`addInputPath, addInputPaths, computeSplitSize, getBlockIndex, getInputPathFilter, getInputPaths, getSplitHosts, isSplitable, listStatus, setInputPathFilter, setInputPaths, setInputPaths, setMinSplitSize`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### CombineFileInputFormat

    public CombineFileInputFormat()

  default constructor

Method Detail

### setMaxSplitSize

    protected void setMaxSplitSize(long maxSplitSize)

  Specify the maximum size (in bytes) of each split. Each split is approximately equal to the specified size.

### setMinSplitSizeNode

    protected void setMinSplitSizeNode(long minSplitSizeNode)

  Specify the minimum size (in bytes) of each split per node. This applies to data that is left over after combining data on a single node into splits that are of maximum size specified by maxSplitSize. This leftover data will be combined into its own split if its size exceeds minSplitSizeNode.

### setMinSplitSizeRack

    protected void setMinSplitSizeRack(long minSplitSizeRack)

  Specify the minimum size (in bytes) of each split per rack. This applies to data that is left over after combining data on a single rack into splits that are of maximum size specified by maxSplitSize. This leftover data will be combined into its own split if its size exceeds minSplitSizeRack.

### createPool

    protected void createPool(JobConf conf,
                              List<PathFilter> filters)

  Create a new pool and add the filters to it. A split cannot have files from different pools.

### createPool

    protected void createPool(JobConf conf,
                              PathFilter... filters)

  Create a new pool and add the filters to it. A pathname can satisfy any one of the specified filters. A split cannot have files from different pools.

### getSplits

    public InputSplit[] getSplits(JobConf job,
                                  int numSplits)
                           throws IOException

  Description copied from class: `FileInputFormat`
  Splits files returned by `FileInputFormat.listStatus(JobConf)` when they're too big.

  Specified by:
    `getSplits` in interface `InputFormat<K,V>`
  Overrides:
    `getSplits` in class `FileInputFormat<K,V>`
  Parameters:
    `job` - job configuration.
    `numSplits` - the desired number of splits, a hint.
  Returns:
    an array of `InputSplit`s for the job.
  Throws:
    `IOException`

### getRecordReader

    public abstract RecordReader<K,V> getRecordReader(InputSplit split,
                                                      JobConf job,
                                                      Reporter reporter)
                                               throws IOException

  This is not implemented yet.

  Specified by:
    `getRecordReader` in interface `InputFormat<K,V>`
  Specified by:
    `getRecordReader` in class `FileInputFormat<K,V>`
  Parameters:
    `split` - the `InputSplit`
    `job` - the job that this split belongs to
  Returns:
    a `RecordReader`
  Throws:
    `IOException`

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