001/*
002    Licensed to the Apache Software Foundation (ASF) under one
003    or more contributor license agreements.  See the NOTICE file
004    distributed with this work for additional information
005    regarding copyright ownership.  The ASF licenses this file
006    to you under the Apache License, Version 2.0 (the
007    "License"); you may not use this file except in compliance
008    with the License.  You may obtain a copy of the License at
009
010       http://www.apache.org/licenses/LICENSE-2.0
011
012    Unless required by applicable law or agreed to in writing,
013    software distributed under the License is distributed on an
014    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015    KIND, either express or implied.  See the License for the
016    specific language governing permissions and limitations
017    under the License.  
018 */
019
020package org.apache.wiki.event;
021
022import org.apache.wiki.WikiEngine;
023
024/**
025  * WikiEngineEvent indicates a change in the state of the WikiEngine.
026  * 
027  * @see     org.apache.wiki.event.WikiEvent
028  * @since   2.4.20
029  */
030public class WikiEngineEvent extends WikiEvent {
031
032    private static final long serialVersionUID = 1829433967558773970L;
033
034    /** Indicates a WikiEngine initialization event, fired as the 
035      * wiki service is being initialized (in progress). */
036    public static final int INITIALIZING   = -1;
037
038    /** Indicates a WikiEngine initialized event, fired after the 
039      * wiki service is fully available. */
040    public static final int INITIALIZED    = 0;
041
042    /** Indicates a WikiEngine closing event, fired as a signal that
043      * the wiki service is shutting down. */
044    public static final int SHUTDOWN       = 1;
045
046    /** Indicates a WikiEngine stopped event, fired after halting the wiki service.
047      * A WikiEngine in this state is not expected to provide further services. 
048      */
049    public static final int STOPPED        = 2;
050
051    private WikiEngine m_engine;
052
053     /**
054      *  Constructs an instance of this event.
055      * @param eventSource  the Object that is the source of the event,
056      * which <b>must</b> be the WikiEngine. If it is not, this
057      * method thows a ClassCastException
058      * @param type the event type
059      */
060    public WikiEngineEvent( Object eventSource, int type ) {
061        super( eventSource, type );
062        m_engine = (WikiEngine)eventSource;
063    }
064
065    /**
066     *  Sets the type of this event.
067     *
068     * @param type      the type of this WikiEngineEvent.
069     */
070    protected void setType( int type ) {
071        if ( type >= INITIALIZING && type <= STOPPED ) {
072            super.setType(type);
073        } else {
074            super.setType(ERROR);
075        }
076    }
077
078    /**
079     *  Returns the WikiEngine that spawned this event.
080     *
081     * @return  the WikiEngine that spawned this event.
082     */
083    public WikiEngine getEngine()
084    {
085        return m_engine;
086    }
087
088   /**
089     * Returns <code>true</code> if the int value is a WikiPageEvent type.
090     * @param type the event type
091     * @return the result
092     */
093    public static boolean isValidType( int type )
094    {
095        return type >= INITIALIZING && type <= STOPPED;
096    }
097
098    /**
099     *  Returns a textual representation of the event type.
100     *
101     * @return a String representation of the type
102     */
103    public final String eventName() {
104        switch ( getType() ) {
105            case INITIALIZING:         return "INITIALIZING";
106            case INITIALIZED:          return "INITIALIZED";
107            case SHUTDOWN:             return "SHUTDOWN";
108            case STOPPED:              return "STOPPED";
109            default:                   return super.eventName();
110        }
111    }
112
113    /**
114     *  Returns a human-readable description of the event type.
115     *
116     * @return a String description of the type
117     */
118    public final String getTypeDescription() {
119        switch ( getType() ) {
120            case INITIALIZING:         return "wiki engine initializing";
121            case INITIALIZED:          return "wiki engine initialized";
122            case SHUTDOWN:             return "wiki engine shutting down";
123            case STOPPED:              return "wiki engine stopped";
124            default:                   return super.getTypeDescription();
125        }
126    }
127
128}