filter input with validation on models

<?php
/**
 * Application_Model_User
 *
 * Contains the minimum requirements to identify a specific user to the system.
 *
 * @category    Prozf
 * @package     Application_Model
 *
 */
class Application_Model_User
{
    /**
     * @var     int The ID of a user
     */
    protected $_id;
    /**
     * @var     string The full name of a user
     */
    protected $_fullname;
    /**
     * @var     string The email address of a user
     */
    protected $_email;
    /**
     * @var     string The password of a user
     */
    protected $_password;
    /**
     * @var     array List of filters used on the individual properties
     */
    protected $_filters;
    /**
     * @var     array List of validators used on the individual properties
     */
    protected $_validators;
    /**
     * Constructor class for this User
     *
     * @param   null|string|array $fullname
     * @param   null|string $email
     * @param   null|string $password
     */
    public function __construct($fullname = null, $email = null, $password = null)
    {
        $this->_filters = array (
            'id'        => new Zend_Filter_Int(),
            'fullname'  => array (
                new Zend_Filter_StringTrim(),
                new Zend_Filter_Alnum(true),
                new Zend_Filter_StripTags(),
            ),
            'email'     => array (
                new Zend_Filter_StringTrim(),
                new Zend_Filter_StringToLower(),
                new Zend_Filter_StripTags(),
            ),
        );
        $this->_validators = array (
            'id' => array (
                new Zend_Validate_Int(),
                new Zend_Validate_GreaterThan(-1),
            ),
            'fullname' => array (
                new Prozf_Validate_Mwop(),
                new Zend_Validate_StringLength(array ('min' => 4, 'max' => 50)),
            ),
            'email'    => array (
                'EmailAddress',
                new Zend_Validate_StringLength(array ('min' => 4, 'max' => 50)),
            ),
            'password' => array (
                new Prozf_Validate_PasswordStrength(
                    Prozf_Validate_PasswordStrength::PASSWD_MEDIUM),
                new Zend_Validate_StringLength(array ('min' => 4)),
            ),
        );
        if (null !== $fullname && (is_array($fullname) || $fullname instanceof Zend_Db_Table_Row)) {
            $this->populate($fullname);
        }
        if (null !== $fullname && is_string($fullname)) {
            $this->setFullname($fullname);
        }
        if (null !== $fullname && is_string($email)) {
            $this->setEmail($email);
        }
        if (null !== $password && is_string($password)) {
            $this->setPassword($password);
        }
    }
    /**
     * Sets the sequence ID for a User
     *
     * @param   int $id
     * @throws  UnexpectedValueException
     * @return  Application_Model_User
     */
    public function setId($id)
    {
        $input = new Zend_Filter_Input($this->_filters, $this->_validators);
        $input->setData(array ('id' => $id));

        if (!$input->isValid('id')) {
            throw new UnexpectedValueException('Wrong value for ID');
        }
        $this->_id = (int) $input->id;
        return $this;
    }
    /**
     * Retrieves the sequence ID from a User
     *
     * @return  int
     */
    public function getId()
    {
        return $this->_id;
    }
    /**
     * Sets the full name for a User
     *
     * @param   string $fullname
     * @throws  UnexpectedValueException
     * @return  Application_Model_User
     */
    public function setFullname($fullname)
    {
        $input = new Zend_Filter_Input($this->_filters, $this->_validators);
        $input->setData(array ('fullname' => $fullname));

        if (!$input->isValid('fullname')) {
            throw new UnexpectedValueException('Wrong value for full name');
        }
        $this->_fullname = $input->fullname;
        return $this;
    }
    /**
     * Retrieves the full name from a User
     *
     * @return  string
     */
    public function getFullname()
    {
        return $this->_fullname;
    }
    /**
     * Sets the email address for a User
     *
     * @param   string $email
     * @throws  UnexpectedValueException
     * @return  Application_Model_User
     */
    public function setEmail($email)
    {
        $input = new Zend_Filter_Input($this->_filters, $this->_validators);
        $input->setData(array ('email' => $email));

        if (!$input->isValid('email')) {
            throw new UnexpectedValueException('Wrong value for email');
        }

        $this->_email = $input->email;
        return $this;
    }
    /**
     * Retrieves the email address from a User
     *
     * @return  string
     */
    public function getEmail()
    {
        return $this->_email;
    }
    /**
     * Sets the password for a User
     *
     * @param   string $password
     * @throws  UnexpectedValueException
     * @return  Application_Model_User
     */
    public function setPassword($password)
    {
        $input = new Zend_Filter_Input($this->_filters, $this->_validators);
        $input->setData(array ('password' => $password));

        if (!$input->isValid('password')) {
            throw new UnexpectedValueException('Wrong value for password');
        }

        $this->_password = $input->password;
        return $this;
    }
    /**
     * Retrieve the password from a User
     */
    public function getPassword()
    {
        return $this->_password;
    }
    /**
     * Populates this User profile with an array
     *
     * @param   array $data
     * @return  Application_Model_User
     */
    public function populate($data)
    {
        if (is_array($data)) {
            $data = new ArrayObject($data, ArrayObject::ARRAY_AS_PROPS);
        }
        if (isset ($data->id)) $this->setId($data->id);
        if (isset ($data->fullname)) $this->setFullname($data->fullname);
        if (isset ($data->email)) $this->setEmail($data->email);
        if (isset ($data->password)) $this->setPassword($data->password);
        return $this;
    }
    /**
     * Converts this User data into an array
     *
     * @return  array
     */
    public function toArray()
    {
        return array (
            'id'       => $this->getId(),
            'fullname' => $this->getFullname(),
            'email'    => $this->getEmail(),
            'password' => $this->getPassword(),
        );
    }
}