001 /*--------------------------------------------------------------------------+ 002 $Id: IdentifierBasedComparatorBase.java 26283 2010-02-18 11:18:57Z juergens $ 003 | | 004 | Copyright 2005-2010 Technische Universitaet Muenchen | 005 | | 006 | Licensed under the Apache License, Version 2.0 (the "License"); | 007 | you may not use this file except in compliance with the License. | 008 | You may obtain a copy of the License at | 009 | | 010 | http://www.apache.org/licenses/LICENSE-2.0 | 011 | | 012 | Unless required by applicable law or agreed to in writing, software | 013 | distributed under the License is distributed on an "AS IS" BASIS, | 014 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 015 | See the License for the specific language governing permissions and | 016 | limitations under the License. | 017 +--------------------------------------------------------------------------*/ 018 package edu.tum.cs.commons.collections; 019 020 import java.util.Comparator; 021 022 /** 023 * Base class for comparators that compare to objects by comparing a suitable 024 * object identifier. 025 * 026 * @author deissenb 027 * @author $Author: juergens $ 028 * @version $Rev: 26283 $ 029 * @levd.rating GREEN Hash: FFF69AADA13F4571BB8935BD37068935 030 */ 031 public abstract class IdentifierBasedComparatorBase<I extends Comparable<I>, T> 032 implements Comparator<T> { 033 034 /** Compare by identifier. */ 035 public int compare(T object1, T object2) { 036 return obtainIdentifier(object1).compareTo(obtainIdentifier(object2)); 037 } 038 039 /** Get identifier for object. */ 040 abstract protected I obtainIdentifier(T object); 041 }