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;
018
019import org.apache.commons.scxml2.model.EnterableState;
020import org.apache.commons.scxml2.model.Transition;
021import org.apache.commons.scxml2.model.TransitionTarget;
022
023/**
024 * Listener interface for observable entities in the SCXML model.
025 * Observable entities include {@link org.apache.commons.scxml2.model.SCXML}
026 * instances (subscribe to all entry, exit and transition notifications),
027 * {@link org.apache.commons.scxml2.model.State} instances (subscribe to
028 * particular entry and exit notifications) and
029 * {@link org.apache.commons.scxml2.model.Transition} instances (subscribe to
030 * particular transitions).
031 *
032 */
033public interface SCXMLListener {
034
035    /**
036     * Handle the entry into a EnterableState.
037     *
038     * @param state The EnterableState entered
039     */
040    void onEntry(EnterableState state);
041
042    /**
043     * Handle the exit out of a EnterableState.
044     *
045     * @param state The EnterableState exited
046     */
047    void onExit(EnterableState state);
048
049    /**
050     * Handle the transition.
051     *
052     * @param from The source TransitionTarget
053     * @param to The destination TransitionTarget
054     * @param transition The Transition taken
055     * @param event The event name triggering the transition
056     */
057    void onTransition(TransitionTarget from, TransitionTarget to,
058            Transition transition, String event);
059
060}
061