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
028 * for a reload operation is detected. From the pay-load of the event
029 * information about the components involved is available.
030 * </p>
031 *
032 * @since 2.0
033 */
034public class ReloadingEvent extends Event
035{
036    /** The common event super type for all reloading events. */
037    public static final EventType<ReloadingEvent> ANY =
038            new EventType<>(Event.ANY, "RELOAD");
039
040    /**
041     * The serial version UID.
042     */
043    private static final long serialVersionUID = 20140701L;
044
045    /** Stores additional data about this event. */
046    private final Object data;
047
048    /**
049     * Creates a new instance of {@code ReloadingEvent} and initializes it.
050     *
051     * @param source the controller which generated this event
052     * @param addData an arbitrary data object to be evaluated by event
053     *        listeners
054     */
055    public ReloadingEvent(final ReloadingController source, final Object addData)
056    {
057        super(source, ANY);
058        data = addData;
059    }
060
061    /**
062     * Returns the {@code ReloadingController} which caused this event.
063     *
064     * @return the responsible {@code ReloadingController}
065     */
066    public ReloadingController getController()
067    {
068        return (ReloadingController) getSource();
069    }
070
071    /**
072     * Returns an object with additional data about the reload operation. This
073     * is the object that was passed to the {@link ReloadingController} when it
074     * was asked to do a reloading check. This is a generic mechanism to pass
075     * arbitrary data to reloading listeners.
076     *
077     * @return additional data about the reload operation (can be <b>null</b>)
078     */
079    public Object getData()
080    {
081        return data;
082    }
083}