Diemuzi

$this->add(
    array(
        'name'       => 'employeeid',
        'required'   => true,
        'filters'    => array(
            array('name' => 'Zend\Filter\StringTrim')
        ),
        'validators' => array(
            array(
                'name'    => 'Zend\Validator\StringLength',
                'options' => array(
                    'encoding' => 'UTF-8',
                    'min'      => 2,
                    'max'      => 20
                ), true
            ),
            array('name' => 'Zend\Validator\Digits', true)
        )
    )
);