public function addFilter(Zend_Filter_Interface $filter, $placement = self::CHAIN_APPEND)
    {
        if ($placement == self::CHAIN_PREPEND) {
            array_unshift($this->_filters, $filter);
        } else {
            $this->_filters[] = $filter;
        }
        return $this;
    }
public function addFilter(Zend_Filter_Interface $filter, $placement = self::CHAIN_APPEND)
    {
        if ($placement == self::CHAIN_PREPEND) {
            array_unshift($this->_filters, $filter);
        } else {
            $this->_filters[] = $filter;
        }
        return $this;
    }
public function addFilter ( Zend_Filter_Interface $ filter , $ placement = self :: CHAIN_APPEND ) { if ( $ placement == self :: CHAIN_PREPEND ) { array_unshift ( $ this -> _filters , $ filter ) ; } else { $ this -> _filters [ ] = $ filter ; } return $ this ; }
Adds a filter to the chain

@param  Zend_Filter_Interface $filter
@param  string $placement
@return Zend_Filter Provides a fluent interface
Adds a filter to the chain