org.apache.commons.collections.comparators

## Class TransformingComparator

- java.lang.Object
- - org.apache.commons.collections.comparators.TransformingComparator

- All Implemented Interfaces:
    Comparator

      public class TransformingComparator
      extends Object
      implements Comparator

  Decorates another Comparator with transformation behavior. That is, the return value from the transform operation will be passed to the decorated `compare` method.
  Since:
    Commons Collections 2.0 (?)
  Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  See Also:
    `Transformer`, `ComparableComparator`

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected Comparator` | `decorated` The decorated comparator.
    `protected Transformer` | `transformer` The transformer being used.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `TransformingComparator(Transformer transformer)` Constructs an instance with the given Transformer and a `ComparableComparator`.
    `TransformingComparator(Transformer transformer, Comparator decorated)` Constructs an instance with the given Transformer and Comparator.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `compare(Object obj1, Object obj2)` Returns the result of comparing the values from the transform operation.

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

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

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

      `equals`

- - ### Field Detail

    - #### decorated

          protected Comparator decorated

      The decorated comparator.

    - #### transformer

          protected Transformer transformer

      The transformer being used.

  - ### Constructor Detail

    - #### TransformingComparator

          public TransformingComparator(Transformer transformer)

      Constructs an instance with the given Transformer and a `ComparableComparator`.
      Parameters:
        `transformer` - what will transform the arguments to `compare`

    - #### TransformingComparator

          public TransformingComparator(Transformer transformer,
                                Comparator decorated)

      Constructs an instance with the given Transformer and Comparator.
      Parameters:
        `transformer` - what will transform the arguments to `compare`
        `decorated` - the decorated Comparator

  - ### Method Detail

    - #### compare

          public int compare(Object obj1,
                    Object obj2)

      Returns the result of comparing the values from the transform operation.
      Specified by:
        `compare` in interface `Comparator`
      Parameters:
        `obj1` - the first object to transform then compare
        `obj2` - the second object to transform then compare
      Returns:
        negative if obj1 is less, positive if greater, zero if equal

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