/**
* Returns true if and only if $value contains only alphabetic characters
*
* @param string $value
* @return boolean
*/
public function isValid($value)
{
if (!is_string($value)) {
$this->_error(self::INVALID);
return false;
}
$this->_setValue($value);
if ('' === $value) {
$this->_error(self::STRING_EMPTY);
return false;
}
if (null === self::$_filter) {
self::$_filter = new \Zend\Filter\Alpha();
}
self::$_filter->allowWhiteSpace = $this->allowWhiteSpace;
if ($value !== self::$_filter->filter($value)) {
$this->_error(self::NOT_ALPHA);
return false;
}
return true;
}
