FooFieldset.php

<?php

namespace My\Form;

use Zend\Form\Element;
use Zend\Form\Fieldset;
use Zend\InputFilter\InputFilterProviderInterface;
use Zend\Validator\InArray;

/**
 * Class FooFieldset
 * @package My\Form
 */
class FooFieldset extends Fieldset implements InputFilterProviderInterface
{
    /**
     * Constructor.
     *
     * @param string|null $name
     * @param array $options
     */
    public function __construct($name = null, $options = [])
    {
        parent::__construct($name, $options);

        $select = (new Element\Select('code'))
            ->setAttributes(['options' => ['' => '', 'a' => 'Option 1', 'b' => 'Option 2', 'c' => 'Option 3']]);

        $this->add($select);
    }

    /**
     * Get the input filter specification.
     *
     * @return array
     */
    public function getInputFilterSpecification()
    {
        $validCodes = ['' => '', 'a' => 'Option 1', 'b' => 'Option 2', 'c' => 'Option 3'];
        $inArrayValidator = (new InArray())->setHaystack($validCodes)->setStrict(InArray::COMPARE_STRICT);

        return [
            'code' => [
                'required' => true,
                'filters' => [
                    ['name' => 'Zend\Filter\StringTrim'],
                    ['name' => 'Zend\I18n\Filter\Alpha'],
                    ['name' => 'Zend\Filter\StringToLower'],
                ],
                'validators' => [
                    ['name' => 'Zend\Validator\NotEmpty'],
                    $inArrayValidator,
                ],
            ],
        ];
    }

    /**
     * {@inheritDoc}
     */
    public function getMessages($elementName = null)
    {
        // TODO - This function exists as a work around for https://github.com/zendframework/zf2/issues/5265
        $messages = parent::getMessages($elementName);
        if (null === $elementName) {
            foreach ($this->messages as $error => $message) {
                $messages[$error] = $message;
            }
        }

        return $messages;
    }

    /**
     * {@inheritDoc}
     */
    public function setMessages($messages)
    {
        // TODO - This function exists as a work around for https://github.com/zendframework/zf2/issues/5265
        foreach ($messages as $key => $messageSet) {
            if (!$this->has($key)) {
                $this->messages[$key] = $messageSet;
            }
        }

        parent::setMessages($messages);
    }
}