001/*-------------------------------------------------------------------------+
002|                                                                          |
003| Copyright 2005-2011 The ConQAT Project                                   |
004|                                                                          |
005| Licensed under the Apache License, Version 2.0 (the "License");          |
006| you may not use this file except in compliance with the License.         |
007| You may obtain a copy of the License at                                  |
008|                                                                          |
009|    http://www.apache.org/licenses/LICENSE-2.0                            |
010|                                                                          |
011| Unless required by applicable law or agreed to in writing, software      |
012| distributed under the License is distributed on an "AS IS" BASIS,        |
013| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
014| See the License for the specific language governing permissions and      |
015| limitations under the License.                                           |
016+-------------------------------------------------------------------------*/
017package org.conqat.lib.commons.collections;
018
019import java.util.Comparator;
020
021/**
022 * Base class for comparators that compare to objects by comparing a suitable
023 * object identifier.
024 * 
025 * @author deissenb
026 */
027public abstract class IdentifierBasedComparatorBase<I extends Comparable<I>, T> implements Comparator<T> {
028
029        /** Compare by identifier. */
030        @Override
031        public int compare(T object1, T object2) {
032                return obtainIdentifier(object1).compareTo(obtainIdentifier(object2));
033        }
034
035        /** Get identifier for object. */
036        abstract protected I obtainIdentifier(T object);
037}