org.apache.commons.io.comparator

## Class CompositeFileComparator

- java.lang.Object
- - org.apache.commons.io.comparator.CompositeFileComparator

- All Implemented Interfaces:
    Serializable, Comparator<File>

      public class CompositeFileComparator
      extends Object
      implements Serializable

  Compare two files using a set of delegate file `Comparator`.

  This comparator can be used to sort lists or arrays of files by combining a number other comparators.

  Example of sorting a list of files by type (i.e. directory or file) and then by name:

             CompositeFileComparator comparator =
                             new CompositeFileComparator(
                                       (AbstractFileComparator) DirectoryFileComparator.DIRECTORY_COMPARATOR,
                                       (AbstractFileComparator) NameFileComparator.NAME_COMPARATOR);
             List<File> list = ...
             comparator.sort(list);

  Since:
    2.0
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `CompositeFileComparator(Comparator<File>... delegates)` Create a composite comparator for the set of delegate comparators.
    `CompositeFileComparator(Iterable<Comparator<File>> delegates)` Create a composite comparator for the set of delegate comparators.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `compare(File file1, File file2)` Compare the two files using delegate comparators.
    `File[]` | `sort(File... files)` Sort an array of files.
    `List<File>` | `sort(List<File> files)` Sort a List of files.
    `String` | `toString()` String representation of this file comparator.

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

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

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

      `comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong`

- - ### Constructor Detail

    - #### CompositeFileComparator

          public CompositeFileComparator(Comparator<File>... delegates)

      Create a composite comparator for the set of delegate comparators.
      Parameters:
        `delegates` - The delegate file comparators

    - #### CompositeFileComparator

          public CompositeFileComparator(Iterable<Comparator<File>> delegates)

      Create a composite comparator for the set of delegate comparators.
      Parameters:
        `delegates` - The delegate file comparators

  - ### Method Detail

    - #### compare

          public int compare(File file1,
                             File file2)

      Compare the two files using delegate comparators.
      Specified by:
        `compare` in interface `Comparator<File>`
      Parameters:
        `file1` - The first file to compare
        `file2` - The second file to compare
      Returns:
        the first non-zero result returned from the delegate comparators or zero.

    - #### toString

          public String toString()

      String representation of this file comparator.
      Returns:
        String representation of this file comparator

    - #### sort

          public File[] sort(File... files)

      Sort an array of files.

      This method uses `Arrays.sort(Object[], Comparator)` and returns the original array.

      Parameters:
        `files` - The files to sort, may be null
      Returns:
        The sorted array
      Since:
        2.0

    - #### sort

          public List<File> sort(List<File> files)

      Sort a List of files.

      This method uses `Collections.sort(List, Comparator)` and returns the original list.

      Parameters:
        `files` - The files to sort, may be null
      Returns:
        The sorted list
      Since:
        2.0

Copyright © 2002–2020 The Apache Software Foundation. All rights reserved.