DirectoryFileComparator (Commons IO 2.5)
Date: 2016-12-01

org.apache.commons.io.comparator

## Class DirectoryFileComparator

- java.lang.Object
- - org.apache.commons.io.comparator.AbstractFileComparator
  - - org.apache.commons.io.comparator.DirectoryFileComparator

- All Implemented Interfaces:
    java.io.Serializable, java.util.Comparator<java.io.File>

      public class DirectoryFileComparator
      extends AbstractFileComparator
      implements java.io.Serializable

  Compare two files using the `File.isDirectory()` method.

  This comparator can be used to sort lists or arrays by directories and files.

  Example of sorting a list of files/directories using the `DIRECTORY_COMPARATOR` singleton instance:

             List<File> list = ...
             ((AbstractFileComparator) DirectoryFileComparator.DIRECTORY_COMPARATOR).sort(list);

  Example of doing a reverse sort of an array of files/directories using the `DIRECTORY_REVERSE` singleton instance:

             File[] array = ...
             ((AbstractFileComparator) DirectoryFileComparator.DIRECTORY_REVERSE).sort(array);

  Since:
    2.0
  Version:
    $Id: DirectoryFileComparator.java 1642757 2014-12-01 21:09:30Z sebb $
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static java.util.Comparator<java.io.File>` | `DIRECTORY_COMPARATOR` Singleton default comparator instance
    `static java.util.Comparator<java.io.File>` | `DIRECTORY_REVERSE` Singleton reverse default comparator instance
    `private static long` | `serialVersionUID`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `DirectoryFileComparator()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `compare(java.io.File file1, java.io.File file2)` Compare the two files using the `File.isDirectory()` method.
    `private int` | `getType(java.io.File file)` Convert type to numeric value.

    - ### Methods inherited from class org.apache.commons.io.comparator.AbstractFileComparator

      `sort, sort, toString`

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

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

    - ### Methods inherited from interface java.util.Comparator

      `equals`

- - ### Field Detail

    - #### serialVersionUID

          private static final long serialVersionUID

      See Also:
        Constant Field Values

    - #### DIRECTORY_COMPARATOR

          public static final java.util.Comparator<java.io.File> DIRECTORY_COMPARATOR

      Singleton default comparator instance

    - #### DIRECTORY_REVERSE

          public static final java.util.Comparator<java.io.File> DIRECTORY_REVERSE

      Singleton reverse default comparator instance

  - ### Constructor Detail

    - #### DirectoryFileComparator

          public DirectoryFileComparator()

  - ### Method Detail

    - #### compare

          public int compare(java.io.File file1,
                    java.io.File file2)

      Compare the two files using the `File.isDirectory()` method.
      Specified by:
        `compare` in interface `java.util.Comparator<java.io.File>`
      Parameters:
        `file1` - The first file to compare
        `file2` - The second file to compare
      Returns:
        the result of calling file1's `File.compareTo(File)` with file2 as the parameter.

    - #### getType

          private int getType(java.io.File file)

      Convert type to numeric value.
      Parameters:
        `file` - The file
      Returns:
        1 for directories and 2 for files

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