org.apache.commons.collections.comparators
Class ReverseComparator<T>

java.lang.Object
  org.apache.commons.collections.comparators.ReverseComparator<T>

All Implemented Interfaces:

Serializable, Comparator<T>

public class ReverseComparator<T>
extends Object
implements Comparator<T>, Serializable

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

Since:

Commons Collections 2.0

Version:

$Revision: 1.1.1.1 $ $Date: 2005/05/23 04:34:11 $

Author:

Henri Yandell, Matt Hall, John Watkinson, Michael A. Smith

See Also:

Collections.reverseOrder(), Serialized Form

Constructor Summary

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

Method Summary

int	compare(T obj1, T 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.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReverseComparator

public ReverseComparator(Comparator<T> comparator)

Creates a comparator that inverts the comparison of the given comparator. Pass in a ComparableComparator for reversing the natural order, as per Collections.reverseOrder().

Parameters:

comparator - Comparator to reverse

Method Detail

compare

public int compare(T obj1,
                   T obj2)

Compares two objects in reverse order.

Specified by:

compare in interface Comparator<T>

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

hashCode

public int hashCode()

Implement a hash code for this comparator that is consistent with equals.

Overrides:

hashCode in class Object

Returns:

a suitable hash code

Since:

Commons Collections 3.0

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.

Specified by:

equals in interface Comparator<T>

Overrides:

equals in class Object

Parameters:

object - the object to compare to

Returns:

true if equal

Since:

Commons Collections 3.0