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.commons.scxml2.model;
018
019import java.util.Comparator;
020
021/**
022 * DocumentOrder is implemented by {@link EnterableState} and {@link Transition} elements in the SCXML document
023 * representing their document order,
024 * <p>
025 *   They are ordered with ancestor states before their descendant states,
026 *   and the transitions within a state in document order before any descendant states.
027 * </p>
028 * <p>Note: it is assumed there will be no more than Integer.MAX_VALUE of such elements in a single SCXML document</p>
029 */
030public interface DocumentOrder {
031
032    Comparator<DocumentOrder> documentOrderComparator = new Comparator<DocumentOrder>() {
033        @Override
034        public int compare(final DocumentOrder o1, final DocumentOrder o2) {
035            return o1.getOrder() - o2.getOrder();
036        }
037    };
038
039    Comparator<DocumentOrder> reverseDocumentOrderComparator = new Comparator<DocumentOrder>() {
040        @Override
041        public int compare(final DocumentOrder o1, final DocumentOrder o2) {
042            return o2.getOrder() - o1.getOrder();
043        }
044    };
045
046    /**
047     * @return the relative document order within the SCXML document of this element
048     */
049    int getOrder();
050}