/**
            Retains only the specified items in a list.
            
            @param items: List of elements to keep.
            @return Returns <code>true</code> if the list was changed as a result of the call; otherwise <code>false</code>.
        */
        public function retainItems(items:IList):Boolean {
            return ArrayUtil.retainItems(this._collection, items.toArray());
        }
        
        /**
            Replaces an item at a specified position.
            
            @para