    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