org.apache.commons.collections.comparators
Class ReverseComparator

java.lang.Object
  |
  +--org.apache.commons.collections.comparators.ReverseComparator

All Implemented Interfaces:

Comparator, Serializable

public class ReverseComparator

extends Object

implements Comparator, Serializable

Reverses the order of another comparator by reversing the arguments to its compare method.

Since:

Commons Collections 2.0

Version:

$Revision: 1.17 $ $Date: 2004/01/14 21:43:18 $

Author:

Henri Yandell, Michael A. Smith

See Also:

Collections.reverseOrder(), Serialized Form

Constructor Summary

ReverseComparator()
Creates a comparator that compares objects based on the inverse of their natural ordering.

ReverseComparator(Comparator comparator)
Creates a comparator that inverts the comparison of the given comparator.

Method Summary

int	compare(Object o1, Object o2)
boolean	equals(Object that) Returns true iff that Object is is a Comparator whose ordering is known to be equivalent to mine.
int	hashCode() Implement a hash code for this comparator that is consistent with equals(java.lang.Object).

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReverseComparator

public ReverseComparator()

Creates a comparator that compares objects based on the inverse of their natural ordering. Using this Constructor will create a ReverseComparator that is functionally identical to the Comparator returned by java.util.Collections.reverseOrder().

See Also:

Collections.reverseOrder()

ReverseComparator

public ReverseComparator(Comparator comparator)

Creates a comparator that inverts the comparison of the given comparator. If you pass in null, the ReverseComparator defaults to reversing the natural order, as per Collections.reverseOrder().

Parameters:

comparator - Comparator to reverse

Method Detail

compare

public int compare(Object o1,
                   Object o2)

Specified by:

compare in interface Comparator

hashCode

public int hashCode()

Implement a hash code for this comparator that is consistent with equals(java.lang.Object).

Overrides:

hashCode in class Object

Since:

Commons Collections 3.0

equals

public boolean equals(Object that)

Returns true iff that Object is is a Comparator whose ordering is known to be equivalent to mine.

This implementation returns true iff that.getClass() equals this.getClass(), and the underlying comparators are equal. Subclasses may want to override this behavior to remain consistent with the Comparator.equals(java.lang.Object) contract.

Specified by:

equals in interface Comparator

Overrides:

equals in class Object

Since:

Commons Collections 3.0