public function add($element)
    {
        if (!$this->contains($element)) {
            $hashIndex = $this->hashIndex($element);

            $this->_items[$hashIndex] = $element;
            $this->_iterator = null;
            return true;
        } else {
            // element already exist
            return false;
        }
    }
public function add($element)
    {
        if (!$this->contains($element)) {
            $hashIndex = $this->hashIndex($element);

            $this->_items[$hashIndex] = $element;
            $this->_iterator = null;
            return true;
        } else {
            // element already exist
            return false;
        }
    }
public function add ( $ element ) { if ( ! $ this -> contains ( $ element ) ) { $ hashIndex = $ this -> hashIndex ( $ element ) ; $ this -> _items [ $ hashIndex ] = $ element ; $ this -> _iterator = null ; return true ; } else { // element already exist return false ; } }
add a element to the end of the collection

@param    mixed      $element        element
@return   bool
add a element to the end of the collection