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AbstractSyncCommand

Kind of class:	internal
Package:	com.bourre.commands
Inherits from:	AbstractCommand
Implements:	ASyncCommand
Known subclasses:	AbstractMultiTween AbstractTween ASyncBatch ASyncCommandSequencer LoopCommand
Classpath:	com.bourre.commands.AbstractSyncCommand
File last modified:	Wednesday, 23 January 2008, 14:47:59
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/*
 * Copyright the original author or authors.
 * 
 * Licensed under the MOZILLA PUBLIC LICENSE, Version 1.1 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.mozilla.org/MPL/MPL-1.1.html
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.bourre.commands 
{
    import flash.events.Event;
    
    import com.bourre.events.BasicEvent;
    import com.bourre.events.EventBroadcaster;
    import com.bourre.log.PixlibStringifier;    

    /**
     * <code>AbstractSyncCommand</code> provides a skeleton to create
     * asynchronous stateless commands. As defined in the 
     * <code>ASyncCommand</code> interface, an asynchronous command
     * hasn't finished its process at the end of the <code>execute</code>
     * call. In that context, the command will dispatch an <code>onCommandEnd</code>
     * event to notice its listener of the end of its process.
     * <p>
     * LowRA encourage the creation of stateless commands, it means
     * that commands must realize all their process entirely in
     * the <code>execute</code> call. The constructor of a stateless
     * command should always be empty. In the case of an asynchronous
     * command, the constructor initialize essentials properties which
     * allow command owner to setup the command properly, and to register
     * its <code>FrontController</code> to the command.
     * </p><p>
     * See the <a href="../../../howto/howto-commands.html">How to use
     * the Command pattern implementation in LowRA</a> document for more details
     * on the commands package structure.
     * </p>
     * @author C√©dric N√©h√©mie
     */
    public class AbstractSyncCommand extends AbstractCommand implements ASyncCommand
    {    
        /**
         * Name of the event dispatched at the end of the command's process.
         */
        static public const onCommandEndEVENT : String = "onCommandEnd";
        
        /**
         * The internal event broadcaster.
         */
        protected var _oEB : EventBroadcaster;
        
        /**
         * An event instance used as event object when dispatching
         * the <code>onCommandEnd</code> event to its listener.
         */
        protected var _eOnCommandEnd : BasicEvent;
        
        /**
         * A boolean value which indicates if this command is currently
         * processing.
         */
        protected var _bIsRunning : Boolean;
        
        /**
         * Initializes event dispatching behavior and <code>Runnable</code>
         * implementation
         */
        public function AbstractSyncCommand ()
        {
            _bIsRunning = false;
            _oEB = new EventBroadcaster ( this );
            _eOnCommandEnd = new BasicEvent ( onCommandEndEVENT, this );
        }
        
        /**
         * Adds the passed-in listener as listener for the <code>onCommandEnd</code>
         * event of this command.
         * 
         * @param    listener    object to be added as listener
         * @param    rest        additional arguments such defined by the
         *                         <code>EventBroacaster.addEventListener</code> method
         * @see        com.bourre.events.EventBroacaster#addEventListener() See the
         *             EventBroacaster.addEventListener() documentation
         */
        public function addASyncCommandListener( listener : ASyncCommandListener, ... rest ) : Boolean
        {
            return _oEB.addEventListener.apply( _oEB, rest.length > 0 ? 
                                                [ onCommandEndEVENT, listener ].concat( rest )
                                                : [ onCommandEndEVENT, listener ] );
        }
        
        /**
         * Removes the passed-in listener for listening
         * the <code>onCommandEnd</code> event of this command.
         * 
         * @param    listener    object to be removed as listener
         */
        public function removeASyncCommandListener( listener : ASyncCommandListener ) : Boolean
        {
            return _oEB.removeEventListener( onCommandEndEVENT, listener );
        }

        /**
         * Fires the <code>onCommandEnd</code> event to the listeners
         * of this command. 
         */
        public function fireCommandEndEvent() : void
        {
            _oEB.broadcastEvent( _eOnCommandEnd );
        }
        
        /**
         * By default the implementation of the <code>execute</code> method
         * in the <code>AbstratSyncCommand</code> dispatch immediately the 
         * <code>onCommandEnd</code> event.
         * 
         * @param    e    An event that will be used as data source by the command. 
         */
        public override function execute( e : Event = null) : void
        {
            fireCommandEndEvent();
        }
        
        /**
         * Implementation of the <code>Runnable</code> interface, 
         * a call to <code>run()</code> is equivalent to a call to
         * <code>execute</code> without argument.
         */
        public function run() : void
        {
            execute();
        }
        
        /**
         * Returns <code>true</code> if this command is currently
         * processing.
         * 
         * @return    <code>true</code> if this command is currently
         *             processing
         */
        public function isRunning () : Boolean
        {
            return _bIsRunning;
        }

        /**
         * Returns the string representation of the object.
         * 
         * @return the string representation of the object
         */
        public override function toString():String
        {
            return PixlibStringifier.stringify( this );
        }
    }
}
Name of the event dispatched at the end of the command's process.