org.magicwerk.brownies.collections.helper

Class AnyComparator<T>

java.lang.Object

org.magicwerk.brownies.collections.helper.AnyComparator<T>

Type Parameters:

T - element type

All Implemented Interfaces:

java.util.Comparator<T>

public class AnyComparator<T>
extends java.lang.Object
implements java.util.Comparator<T>

The AnyComparator can compare elements of any object type, even if they do not implement Comparable. As the comparison bases on the identity hash code, order is not stable after serialization.

Version:

$Id: AnyComparator.java 1909 2013-10-10 21:22:36Z origo $

Author:

Thomas Mauch

Field Summary

Fields

Modifier and Type	Field and Description
static AnyComparator	INSTANCE Singleton instance.

Method Summary

Methods

Modifier and Type	Method and Description
int	compare(T key1, T key2) Compares its two arguments for order.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

equals

Field Detail

INSTANCE

public static final AnyComparator INSTANCE

Singleton instance.

Method Detail

compare

public int compare(T key1,
          T key2)

Description copied from interface: java.util.Comparator

Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

In the foregoing description, the notation sgn(expression) designates the mathematical signum function, which is defined to return one of -1, 0, or 1 according to whether the value of expression is negative, zero or positive.

The implementor must ensure that sgn(compare(x, y)) == -sgn(compare(y, x)) for all x and y. (This implies that compare(x, y) must throw an exception if and only if compare(y, x) throws an exception.)

The implementor must also ensure that the relation is transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0.

Finally, the implementor must ensure that compare(x, y)==0 implies that sgn(compare(x, z))==sgn(compare(y, z)) for all z.

It is generally the case, but not strictly required that (compare(x, y)==0) == (x.equals(y)). Generally speaking, any comparator that violates this condition should clearly indicate this fact. The recommended language is "Note: this comparator imposes orderings that are inconsistent with equals."

Specified by:

compare in interface java.util.Comparator<T>

Parameters:

key1 - the first object to be compared.

key2 - the second object to be compared.

Returns:

a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.