Zend_Validate を継承したバリデータには、 検証に失敗したときに使用するメッセージが用意されています。 You can use this information to set your own messages, or to translate existing messages which a validator could return to something different.

These validation messages are constants which can be found at top of each validator class. Let's look into Zend_Validate_GreaterThan for an descriptive example:

protected $_messageTemplates = array(
    self::NOT_GREATER => "'%value%' is not greater than '%min%'",
);

As you can see the constant self::NOT_GREATER refers to the failure and is used as key, and the message itself is used as value of the message array.

You can retrieve all message templates from a validator by using the getMessageTemplates() method. It returns you the above array which contains all messages a validator could return in the case of a failed validation.

$validator = new Zend_Validate_GreaterThan();
$messages  = $validator->getMessageTemplates();

Using the setMessage() method you can set another message to be returned in case of the specified failure.

$validator = new Zend_Validate_GreaterThan();
$validator->setMessage(
    'Please enter a lower value',
    Zend_Validate_GreaterThan::NOT_GREATER
);

The second parameter defines the failure which will be overridden. When you omit this parameter, then the given message will be set for all possible failures of this validator.

$translator = new Zend_Translate(
    array(
        'adapter' => 'array',
        'content' => '/resources/languages',
        'locale'  => $language,
        'scan' => Zend_Translate::LOCALE_DIRECTORY
    )
);
Zend_Validate_Abstract::setDefaultTranslator($translator);

Zend_Validate::setMessageLength(100);