AS3- using quick sort algorithm to sort on an arbitrarily specified attribute of a typed vector.

task_quick_sort.as

    
    /**
    * Some constants we use to choose sorting methods.
    */
    public static const SORT_BY_DATE_START:String = "DATE_START";
    public static const SORT_BY_ID_ASC:String = "ID_ASC";
        
    /** 
    * Example function that calls the quick sort on a vector of some beans
    */
    public static function getTopLevelTasks( taskList:Vector.<Task2>, sortBy:String = SORT_BY_ID_ASC ):Vector.<Task2> {
        var topLevelTasks:Vector.<Task2> = new Vector.<Task2>();
        for( var i:int = 0;  i < taskList.length; i++) {
            if( taskList[i].parentTaskID == 0 || taskList[i].parentTaskID == -1) {
                topLevelTasks.push( taskList[i] );
            }
        }
        
        if( sortBy == SORT_BY_DATE_START ) {
            topLevelTasks = vectorQuickSortByAttr( topLevelTasks, "dateStart" );
        } else if( sortBy == SORT_BY_ID_ASC ) {
            topLevelTasks = vectorQuickSortByAttr( topLevelTasks, "task_id" );
        }
        
        return topLevelTasks;
    }
        
    /***
     * Wamp wamp implement quick sort...
     */
    public static function vectorQuickSortByAttr(tosort:Vector.<Task2>, sortAttr:String):Vector.<Task2> {
        if( tosort.length <= 1) 
            return tosort;
        
        var pivot_index:int = Math.round(Math.random() * (tosort.length - 1));
        var pivot:Task2 = tosort[ pivot_index ];
        // remove pivot from the vector:
        tosort.splice(pivot_index, 1);
        
        var l_list:Vector.<Task2> = new Vector.<Task2>();
        var g_list:Vector.<Task2> = new Vector.<Task2>();
        
        for( var i:int = 0; i < tosort.length; i++ ) { 
            if( tosort[i][sortAttr] > pivot[sortAttr] ) {
                g_list.push( tosort[i] );
            } else {
                l_list.push( tosort[i] );
            }
        }
        // return l_list + pivot + g_list
        l_list.push( pivot )
        return l_list.concat( g_list );
    }