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Merging from -r468106:814127 of collections_jdk5_branch - namely where this code was generified; mostly in r738956. 

Also see the following revisions:

    ------------------------------------------------------------------------
    r643590 | skestle | 2008-04-01 14:36:59 -0700 (Tue, 01 Apr 2008) | 1 line
    
    Added Equator interface for COLLECTIONS-242.
    ------------------------------------------------------------------------


git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@815047 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Henri Yandell 2009-09-15 05:55:04 +00:00
parent 5362395fe9
commit e47b5cf540
1 changed files with 48 additions and 0 deletions
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src/java/org/apache/commons/collections/functors/Equator.java Normal file
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional information regarding
* copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the License. You may obtain a
* copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable
* law or agreed to in writing, software distributed under the License is distributed on an "AS IS"
* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License
* for the specific language governing permissions and limitations under the License.
*/
package org.apache.commons.collections.functors;
import org.apache.commons.collections.map.HashedMap;
/**
* <p>
* An equation function, which determines equality between objects of type T.
* </p>
* <p>
* It is the functional sibling of {@link java.util.Comparator}; {@link Equator} is to
* {@link Object} as {@link java.util.Comparator} is to {@link java.lang.Comparable}.
* </p>
*
* @param <T> the types of object this {@link Equator} can evaluate.
* @author Stephen Kestle
* @since 4.0
*/
public interface Equator<T> {
/**
* Evaluates the two arguments for their equality.
*
* @param o1 the first object to be equated.
* @param o2 the second object to be equated.
* @return whether the two objects are equal.
*/
boolean equate(T o1, T o2);
/**
* Calculates the hash for the object, based on the method of equality used in the equate
* method. This is used for classes that delegate their {@link #equals(Object)} method to an
* Equator (and so must also delegate their {@link #hashCode()} method), or for implementations
* of {@link HashedMap} that use an Equator for the key objects.
*
* @param o the object to calculate the hash for.
* @return the hash of the object.
*/
int hash(T o);
}