public function filter($value, $context = array())
 {
     if (!($field = $this->getField())) {
         throw new Zend_Filter_Exception("Missing currency field in filter");
     }
     if ($customer = $context->{$field}) {
         $this->_currencyId = $customer->currency;
     }
     return parent::filter($value, $context);
 }
 public function filter($value, $context = array())
 {
     if (!($field = $this->getField())) {
         throw new Zend_Filter_Exception("Missing currency field in filter");
     }
     if ($currencyId = App_Util_Array::getItem($context, $field)) {
         $this->_currencyId = $currencyId;
     }
     return parent::filter($value, $context);
 }