jaggregate
Class Comparing

java.lang.Object
  jaggregate.Comparing

public class Comparing
extends Object

Utility class that offers common comparators.

Version:

$Id: Comparing.java,v 1.5 2008/10/03 19:01:23 pholser Exp $

Author:

Paul Holser

Method Summary

static <T extends Comparable<? super T>> Comparator<T>	byNaturalOrdering() Answers a comparator that compares its two Comparable arguments according to their natural ordering; that is, by how they answer compareTo.
static <T> Comparator<T>	nullSafe(Comparator<T> comparator) Answers a comparator that defends against null actual arguments to its wrapped comparator's compare method.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

nullSafe

public static <T> Comparator<T> nullSafe(Comparator<T> comparator)

Answers a comparator that defends against null actual arguments to its wrapped comparator's compare method.

A null value compares "less than" a non-null value.

Type Parameters:

T - the type of elements to be compared

Parameters:

comparator - the comparator to wrap

Returns:

the wrapped comparator

Throws:

NullPointerException - if comparator is null

byNaturalOrdering

public static <T extends Comparable<? super T>> Comparator<T> byNaturalOrdering()

Answers a comparator that compares its two Comparable arguments according to their natural ordering; that is, by how they answer compareTo. The comparator is "null safe".

Type Parameters:

T - the type of elements to be compared

Returns:

a comparator of comparables that answers based on the arguments' natural ordering

See Also:

nullSafe(Comparator)