Zend_Currency_Exception example

        if (!isset($this->_options['name']) || !is_array($options)) {
            $this->_options['name']     = self::getName($options, $this->_options['locale']);
        }

        if (!isset($this->_options['symbol']) || !is_array($options)) {
            $this->_options['symbol']   = self::getSymbol($options, $this->_options['locale']);
        }

        if (($this->_options['currency'] === null) and ($this->_options['name'] === null)) {
            throw new Zend_Currency_Exception("Currency '$options' not found");
        }

        // Get the format         if ((is_array($calloptions) && !isset($calloptions['display']))
                || (!is_array($calloptions) && $this->_options['display'] == self::NO_SYMBOL)) {
            if (!empty($this->_options['symbol'])) {
                $this->_options['display'] = self::USE_SYMBOL;
            } else if (!empty($this->_options['currency'])) {
                $this->_options['display'] = self::USE_SHORTNAME;
            }
        }
    }