eturn (this.indexOf(item) == -1) ? false : true;
        }
        
        /**
            Determines if this list contains all of the elements of the specified list.
            
            @param items: List of elements to be checked for containment.
            @return Returns <code>true</code> if list contains all elements of the list; otherwise <code>false</code>.
        */
        public function containsAll(items:IList):Boolean {
            return ArrayUtil.containsAll(this._collection, items.toA