001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  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.apache.camel.processor.resequencer;
018
019import java.util.Comparator;
020
021/**
022 * A strategy for comparing elements of a sequence.
023 * 
024 * @version 
025 */
026public interface SequenceElementComparator<E> extends Comparator<E> {
027
028    /**
029     * Returns <code>true</code> if <code>o1</code> is an immediate predecessor
030     * of <code>o2</code>.
031     * 
032     * @param o1 a sequence element.
033     * @param o2 a sequence element.
034     * @return true if its an immediate predecessor
035     */
036    boolean predecessor(E o1, E o2);
037    
038    /**
039     * Returns <code>true</code> if <code>o1</code> is an immediate successor
040     * of <code>o2</code>.
041     * 
042     * @param o1 a sequence element.
043     * @param o2 a sequence element.
044     * @return true if its an immediate successor
045     */
046    boolean successor(E o1, E o2);
047
048    /**
049     * Returns <tt>true</tt> if the <code>o1</code> can be used in this comparator.
050     *
051     * @param o1 a sequence element
052     * @return true if its usable for this comparator
053     */
054    boolean isValid(E o1);
055    
056}