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.configuration2.reloading;
018
019import org.apache.commons.configuration2.event.Event;
020import org.apache.commons.configuration2.event.EventType;
021
022/**
023 * <p>
024 * An event that is fired when a reload operation is required.
025 * </p>
026 * <p>
027 * Events of this type are generated by {@link ReloadingController} if the need for a reload operation is detected. From
028 * the pay-load of the event information about the components involved is available.
029 * </p>
030 *
031 * @since 2.0
032 */
033public class ReloadingEvent extends Event {
034    /** The common event super type for all reloading events. */
035    public static final EventType<ReloadingEvent> ANY = new EventType<>(Event.ANY, "RELOAD");
036
037    /**
038     * The serial version UID.
039     */
040    private static final long serialVersionUID = 20140701L;
041
042    /** Stores additional data about this event. */
043    private final Object data;
044
045    /**
046     * Creates a new instance of {@code ReloadingEvent} and initializes it.
047     *
048     * @param source the controller which generated this event
049     * @param addData an arbitrary data object to be evaluated by event listeners
050     */
051    public ReloadingEvent(final ReloadingController source, final Object addData) {
052        super(source, ANY);
053        data = addData;
054    }
055
056    /**
057     * Gets the {@code ReloadingController} which caused this event.
058     *
059     * @return the responsible {@code ReloadingController}
060     */
061    public ReloadingController getController() {
062        return (ReloadingController) getSource();
063    }
064
065    /**
066     * Gets an object with additional data about the reload operation. This is the object that was passed to the
067     * {@link ReloadingController} when it was asked to do a reloading check. This is a generic mechanism to pass arbitrary
068     * data to reloading listeners.
069     *
070     * @return additional data about the reload operation (can be <b>null</b>)
071     */
072    public Object getData() {
073        return data;
074    }
075}