SingletonUtil

/*
    CASA Framework for ActionScript 3.0
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*/
package org.casalib.util {
    import flash.utils.Dictionary;
    
    
    /**
        Provides utility functions for creating and managing singletons and multitons.
        
        @author Aaron Clinger
        @version 05/04/11
    */
    public class SingletonUtil {
        protected static var _singletonMap:Dictionary;
        protected static var _multitonMap:Dictionary;
        
        
        /**
            Creates a singleton out of a class without adapting or extending the class itself.
            
            @param type: The class you want a to created a singleton from.
            @return The singleton instance of the class.
            @example
                
                    var stopwatch:Stopwatch = SingletonUtil.singleton(Stopwatch);
                    stopwatch.start();
                
        */
        public static function singleton(type:Class):* {
            if (SingletonUtil._singletonMap == null)
                SingletonUtil._singletonMap = new Dictionary();
            
            return type in SingletonUtil._singletonMap ? SingletonUtil._singletonMap[type] : SingletonUtil._singletonMap[type] = new type();
        }
        
        /**
            Creates a multiton out of a class without adapting or extending the class itself.
            
            @param type: The class you want a to created a multiton from.
            @param id: An unique name per Class type.
            @return The multiton instance of the class.
            @example
                
                    var stopwatch:Stopwatch = SingletonUtil.multiton(Stopwatch, "MyUniqueWatchId");
                    stopwatch.start();
                
        */
        public static function multiton(type:Class, id:String):* {
            if (SingletonUtil._multitonMap == null)
                SingletonUtil._multitonMap = new Dictionary();
            
            if ( ! (type in SingletonUtil._multitonMap))
                SingletonUtil._multitonMap[type] = new Dictionary();
            
            if ( ! (id in SingletonUtil._multitonMap[type]))
                SingletonUtil._multitonMap[type][id] = new type();
            
            return SingletonUtil._multitonMap[type][id];
        }
    }
}