Added Jonathan Carlson's patch for a Comparator that uses a Transformer
git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@130708 13f79535-47bb-0310-9956-ffa450edef68
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package org.apache.commons.collections.comparators;
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/* ====================================================================
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* The Apache Software License, Version 1.1
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*
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* Copyright (c) 2001 The Apache Software Foundation. All rights
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* reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. The end-user documentation included with the redistribution,
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* if any, must include the following acknowledgment:
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* "This product includes software developed by the
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* Apache Software Foundation (http://www.apache.org/)."
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* Alternately, this acknowledgment may appear in the software itself,
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* if and wherever such third-party acknowledgments normally appear.
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*
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* 4. The names "Apache" and "Apache Software Foundation" and
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* "Apache Commons" must not be used to endorse or promote products
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* derived from this software without prior written permission. For
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* written permission, please contact apache@apache.org.
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*
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* 5. Products derived from this software may not be called "Apache",
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* "Apache Turbine", nor may "Apache" appear in their name, without
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* prior written permission of the Apache Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* ====================================================================
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*
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* This software consists of voluntary contributions made by many
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* individuals on behalf of the Apache Software Foundation. For more
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* information on the Apache Software Foundation, please see
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* <http://www.apache.org/>.
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*/
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import java.util.Comparator;
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import org.apache.commons.collections.Transformer;
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/**
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* Decorates another Comparator with transformation behavior. That is, the
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* return value from the transform operation will be passed to the decorated
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* <CODE>Comparator#compare</CODE> method.
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* <p>
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* @see org.apache.commons.collections.Transformer
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* @see org.apache.commons.collections.comparators.ComparableComparator
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*/
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public class TransformingComparator implements Comparator
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{
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protected Comparator decorated;
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protected Transformer transformer;
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/**
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* Constructs an instance with the given Transformer and a ComparableComparator.
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* @param transformer what will transform the instance.
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*/
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public TransformingComparator(Transformer transformer)
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{
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this(transformer, new ComparableComparator());
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}
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/**
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* Constructs an instance with the given Transformer and Comparator
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* @param decorated the decorated Comparator
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* @param getterName the getter name
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*/
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public TransformingComparator(Transformer transformer, Comparator decorated)
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{
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this.decorated = decorated;
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this.transformer = transformer;
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}
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/**
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* Returns the result of comparing the values from the transform operation.
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* @return the result of comparing the values from the transform operation
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*/
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public int compare(Object o1, Object o2)
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{
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Object value1 = this.transformer.transform(o1);
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Object value2 = this.transformer.transform(o2);
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return this.decorated.compare(value1, value2);
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}
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}
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