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
This commit is contained in:
James Strachan 2002-06-08 06:42:00 +00:00
parent d7f1ac38d0
commit bde0d09c4c
1 changed files with 106 additions and 0 deletions

View File

@ -0,0 +1,106 @@
package org.apache.commons.collections.comparators;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache Commons" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* "Apache Turbine", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.util.Comparator;
import org.apache.commons.collections.Transformer;
/**
* Decorates another Comparator with transformation behavior.&nbsp;That is, the
* return value from the transform operation will be passed to the decorated
* <CODE>Comparator#compare</CODE> method.
* <p>
* @see org.apache.commons.collections.Transformer
* @see org.apache.commons.collections.comparators.ComparableComparator
*/
public class TransformingComparator implements Comparator
{
protected Comparator decorated;
protected Transformer transformer;
/**
* Constructs an instance with the given Transformer and a ComparableComparator.
* @param transformer what will transform the instance.
*/
public TransformingComparator(Transformer transformer)
{
this(transformer, new ComparableComparator());
}
/**
* Constructs an instance with the given Transformer and Comparator
* @param decorated the decorated Comparator
* @param getterName the getter name
*/
public TransformingComparator(Transformer transformer, Comparator decorated)
{
this.decorated = decorated;
this.transformer = transformer;
}
/**
* Returns the result of comparing the values from the transform operation.
* @return the result of comparing the values from the transform operation
*/
public int compare(Object o1, Object o2)
{
Object value1 = this.transformer.transform(o1);
Object value2 = this.transformer.transform(o2);
return this.decorated.compare(value1, value2);
}
}