Callbacks.php

1. 8.x drupal/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/Callbacks.php
2. 8.x drupal/core/modules/system/tests/modules/ajax_forms_test/lib/Drupal/ajax_forms_test/Callbacks.php

<?php

/**
 * @file
 * Definition of Drupal\form_test\Callbacks.
 */
namespace Drupal\form_test;


/**
 * Simple class for testing methods as Form API callbacks.
 */
class Callbacks {

  /**
   * Form element validation handler for 'name' in form_test_validate_form().
   */
  public function validateName(&$element, &$form_state) {
    $triggered = FALSE;
    if ($form_state['values']['name'] == 'element_validate') {

      // Alter the form element.
      $element['#value'] = '#value changed by #element_validate';

      // Alter the submitted value in $form_state.
      form_set_value($element, 'value changed by form_set_value() in #element_validate', $form_state);
      $triggered = TRUE;
    }
    if ($form_state['values']['name'] == 'element_validate_access') {
      $form_state['storage']['form_test_name'] = $form_state['values']['name'];

      // Alter the form element.
      $element['#access'] = FALSE;
      $triggered = TRUE;
    }
    elseif (!empty($form_state['storage']['form_test_name'])) {

      // To simplify this test, just take over the element's value into $form_state.
      form_set_value($element, $form_state['storage']['form_test_name'], $form_state);
      $triggered = TRUE;
    }
    if ($triggered) {

      // Output the element's value from $form_state.
      drupal_set_message(t('@label value: @value', array(
        '@label' => $element['#title'],
        '@value' => $form_state['values']['name'],
      )));

      // Trigger a form validation error to see our changes.
      form_set_error('');
    }
  }

}