org.apache.commons.collections.comparators

Class ReverseComparator

Implemented Interfaces:
Comparator, Serializable

public class ReverseComparator
extends java.lang.Object
implements Comparator, Serializable

Reverses the order of another comparator by reversing the arguments to its compare method.
Version:
$Revision: 1.20 $ $Date: 2004/05/16 11:49:24 $
Authors:
Henri Yandell
Michael A. Smith
Since:
Commons Collections 2.0
See Also:
java.util.Collections.reverseOrder()

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 obj1, Object obj2)
Compares two objects in reverse order.
boolean
equals(Object object)
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.

Constructor Details

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:
java.util.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 java.util.Collections.reverseOrder().
Parameters:
comparator - Comparator to reverse

Method Details

compare

public int compare(Object obj1,
                   Object obj2)
Compares two objects in reverse order.
Parameters:
obj1 - the first object to compare
obj2 - the second object to compare
Returns:
negative if obj1 is less, positive if greater, zero if equal

equals

public boolean equals(Object object)
Returns true iff that Object is is a Comparator whose ordering is known to be equivalent to mine.

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

Parameters:
object - the object to compare to
Returns:
true if equal
Since:
Commons Collections 3.0

hashCode

public int hashCode()
Returns:
a suitable hash code
Since:
Commons Collections 3.0

Copyright © 2001-2006 Apache Software Foundation. All Rights Reserved.