protected function isCacheExpired($fromCurrency, $toCurrency)
    {
        $cacheCreationTime = $this->getCacheCreationTime($fromCurrency, $toCurrency);
        return (time() - $cacheCreationTime) > $this->getCacheTimeOut()->format('%s');
    }
protected function isCacheExpired($fromCurrency, $toCurrency)
    {
        $cacheCreationTime = $this->getCacheCreationTime($fromCurrency, $toCurrency);
        return (time() - $cacheCreationTime) > $this->getCacheTimeOut()->format('%s');
    }
protected function isCacheExpired ( $ fromCurrency , $ toCurrency ) { $ cacheCreationTime = $ this -> getCacheCreationTime ( $ fromCurrency , $ toCurrency ) ; return ( time ( ) - $ cacheCreationTime ) > $ this -> getCacheTimeOut ( ) -> format ( '%s' ) ; }
Checks if cache is expired

@param  string $fromCurrency
@param  string $toCurrency
@return bool
Checks if cache is expired