SequenceFile.Sorter (Hadoop 1.2.1 API)
Date: 2013-07-22

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## org.apache.hadoop.io
Class SequenceFile.Sorter

    java.lang.Object
      org.apache.hadoop.io.SequenceFile.Sorter

Enclosing class:
  SequenceFile

    public static class SequenceFile.Sorter

extends Object

Sorts key/value pairs in a sequence-format file.

For best performance, applications should make sure that the `Writable.readFields(DataInput)` implementation of their keys is very efficient. In particular, it should avoid allocating memory.

Nested Class Summary
`static interface` | `SequenceFile.Sorter.RawKeyValueIterator` The interface to iterate over raw keys/values of SequenceFiles.
`class` | `SequenceFile.Sorter.SegmentDescriptor` This class defines a merge segment.

Constructor Summary
`SequenceFile.Sorter(FileSystem fs, Class<? extends WritableComparable> keyClass, Class valClass, Configuration conf)` Sort and merge files containing the named classes.
`SequenceFile.Sorter(FileSystem fs, RawComparator comparator, Class keyClass, Class valClass, Configuration conf)` Sort and merge using an arbitrary `RawComparator`.

Method Summary
`SequenceFile.Writer` | `cloneFileAttributes(Path inputFile, Path outputFile, Progressable prog)` Clones the attributes (like compression of the input file and creates a corresponding Writer
`int` | `getFactor()` Get the number of streams to merge at once.
`int` | `getMemory()` Get the total amount of buffer memory, in bytes.
`SequenceFile.Sorter.RawKeyValueIterator` | `merge(List<SequenceFile.Sorter.SegmentDescriptor> segments, Path tmpDir)` Merges the list of segments of type `SegmentDescriptor`
`SequenceFile.Sorter.RawKeyValueIterator` | `merge(Path[] inNames, boolean deleteInputs, int factor, Path tmpDir)` Merges the contents of files passed in Path[]
`SequenceFile.Sorter.RawKeyValueIterator` | `merge(Path[] inNames, boolean deleteInputs, Path tmpDir)` Merges the contents of files passed in Path[] using a max factor value that is already set
`void` | `merge(Path[] inFiles, Path outFile)` Merge the provided files.
`SequenceFile.Sorter.RawKeyValueIterator` | `merge(Path[] inNames, Path tempDir, boolean deleteInputs)` Merges the contents of files passed in Path[]
`void` | `setFactor(int factor)` Set the number of streams to merge at once.
`void` | `setMemory(int memory)` Set the total amount of buffer memory, in bytes.
`void` | `setProgressable(Progressable progressable)` Set the progressable object in order to report progress.
`void` | `sort(Path[] inFiles, Path outFile, boolean deleteInput)` Perform a file sort from a set of input files into an output file.
`void` | `sort(Path inFile, Path outFile)` The backwards compatible interface to sort.
`SequenceFile.Sorter.RawKeyValueIterator` | `sortAndIterate(Path[] inFiles, Path tempDir, boolean deleteInput)` Perform a file sort from a set of input files and return an iterator.
`void` | `writeFile(SequenceFile.Sorter.RawKeyValueIterator records, SequenceFile.Writer writer)` Writes records from RawKeyValueIterator into a file represented by the passed writer

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

Constructor Detail

### SequenceFile.Sorter

    public SequenceFile.Sorter(FileSystem fs,
                               Class<? extends WritableComparable> keyClass,
                               Class valClass,
                               Configuration conf)

  Sort and merge files containing the named classes.

### SequenceFile.Sorter

    public SequenceFile.Sorter(FileSystem fs,
                               RawComparator comparator,
                               Class keyClass,
                               Class valClass,
                               Configuration conf)

  Sort and merge using an arbitrary `RawComparator`.

Method Detail

### setFactor

    public void setFactor(int factor)

  Set the number of streams to merge at once.

### getFactor

    public int getFactor()

  Get the number of streams to merge at once.

### setMemory

    public void setMemory(int memory)

  Set the total amount of buffer memory, in bytes.

### getMemory

    public int getMemory()

  Get the total amount of buffer memory, in bytes.

### setProgressable

    public void setProgressable(Progressable progressable)

  Set the progressable object in order to report progress.

### sort

    public void sort(Path[] inFiles,
                     Path outFile,
                     boolean deleteInput)
              throws IOException

  Perform a file sort from a set of input files into an output file.

  Parameters:
    `inFiles` - the files to be sorted
    `outFile` - the sorted output file
    `deleteInput` - should the input files be deleted as they are read?
  Throws:
    `IOException`

### sortAndIterate

    public SequenceFile.Sorter.RawKeyValueIterator sortAndIterate(Path[] inFiles,
                                                                  Path tempDir,
                                                                  boolean deleteInput)
                                                           throws IOException

  Perform a file sort from a set of input files and return an iterator.

  Parameters:
    `inFiles` - the files to be sorted
    `tempDir` - the directory where temp files are created during sort
    `deleteInput` - should the input files be deleted as they are read?
  Returns:
    iterator the RawKeyValueIterator
  Throws:
    `IOException`

### sort

    public void sort(Path inFile,
                     Path outFile)
              throws IOException

  The backwards compatible interface to sort.

  Parameters:
    `inFile` - the input file to sort
    `outFile` - the sorted output file
  Throws:
    `IOException`

### merge

    public SequenceFile.Sorter.RawKeyValueIterator merge(List<SequenceFile.Sorter.SegmentDescriptor> segments,
                                                         Path tmpDir)
                                                  throws IOException

  Merges the list of segments of type `SegmentDescriptor`

  Parameters:
    `segments` - the list of SegmentDescriptors
    `tmpDir` - the directory to write temporary files into
  Returns:
    RawKeyValueIterator
  Throws:
    `IOException`

### merge

    public SequenceFile.Sorter.RawKeyValueIterator merge(Path[] inNames,
                                                         boolean deleteInputs,
                                                         Path tmpDir)
                                                  throws IOException

  Merges the contents of files passed in Path[] using a max factor value that is already set

  Parameters:
    `inNames` - the array of path names
    `deleteInputs` - true if the input files should be deleted when unnecessary
    `tmpDir` - the directory to write temporary files into
  Returns:
    RawKeyValueIteratorMergeQueue
  Throws:
    `IOException`

### merge

    public SequenceFile.Sorter.RawKeyValueIterator merge(Path[] inNames,
                                                         boolean deleteInputs,
                                                         int factor,
                                                         Path tmpDir)
                                                  throws IOException

  Merges the contents of files passed in Path[]

  Parameters:
    `inNames` - the array of path names
    `deleteInputs` - true if the input files should be deleted when unnecessary
    `factor` - the factor that will be used as the maximum merge fan-in
    `tmpDir` - the directory to write temporary files into
  Returns:
    RawKeyValueIteratorMergeQueue
  Throws:
    `IOException`

### merge

    public SequenceFile.Sorter.RawKeyValueIterator merge(Path[] inNames,
                                                         Path tempDir,
                                                         boolean deleteInputs)
                                                  throws IOException

  Merges the contents of files passed in Path[]

  Parameters:
    `inNames` - the array of path names
    `tempDir` - the directory for creating temp files during merge
    `deleteInputs` - true if the input files should be deleted when unnecessary
  Returns:
    RawKeyValueIteratorMergeQueue
  Throws:
    `IOException`

### cloneFileAttributes

    public SequenceFile.Writer cloneFileAttributes(Path inputFile,
                                                   Path outputFile,
                                                   Progressable prog)
                                            throws IOException

  Clones the attributes (like compression of the input file and creates a corresponding Writer

  Parameters:
    `inputFile` - the path of the input file whose attributes should be cloned
    `outputFile` - the path of the output file
    `prog` - the Progressable to report status during the file write
  Returns:
    Writer
  Throws:
    `IOException`

### writeFile

    public void writeFile(SequenceFile.Sorter.RawKeyValueIterator records,
                          SequenceFile.Writer writer)
                   throws IOException

  Writes records from RawKeyValueIterator into a file represented by the passed writer

  Parameters:
    `records` - the RawKeyValueIterator
    `writer` - the Writer created earlier
  Throws:
    `IOException`

### merge

    public void merge(Path[] inFiles,
                      Path outFile)
               throws IOException

  Merge the provided files.

  Parameters:
    `inFiles` - the array of input path names
    `outFile` - the final output file
  Throws:
    `IOException`

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