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 */
017 package org.apache.commons.scxml;
018
019 import org.apache.commons.scxml.model.Transition;
020 import org.apache.commons.scxml.model.TransitionTarget;
021
022 /**
023 * Listener interface for observable entities in the SCXML model.
024 * Observable entities include {@link org.apache.commons.scxml.model.SCXML}
025 * instances (subscribe to all entry, exit and transition notifications),
026 * {@link org.apache.commons.scxml.model.State} instances (subscribe to
027 * particular entry and exit notifications) and
028 * {@link org.apache.commons.scxml.model.Transition} instances (subscribe to
029 * particular transitions).
030 *
031 */
032 public interface SCXMLListener {
033
034 /**
035 * Handle the entry into a TransitionTarget.
036 *
037 * @param state The TransitionTarget entered
038 */
039 void onEntry(TransitionTarget state);
040
041 /**
042 * Handle the exit out of a TransitionTarget.
043 *
044 * @param state The TransitionTarget exited
045 */
046 void onExit(TransitionTarget state);
047
048 /**
049 * Handle the transition.
050 *
051 * @param from The source TransitionTarget
052 * @param to The destination TransitionTarget
053 * @param transition The Transition taken
054 */
055 void onTransition(TransitionTarget from, TransitionTarget to,
056 Transition transition);
057
058 }
059