class views_handler_field_prerender_list

class views_handler_field_prerender_list extends views_handler_field {

  /**
   * Stores all items which are used to render the items.
   *
   * It should be keyed first by the id of the base table, for example nid.
   * The second key is the id of the thing which is displayed multiple times
   * per row, for example the tid.
   *
   * @var array
   */
  public $items = array();

  /**
   * {@inheritdoc}
   */
  public function option_definition() {
    $options = parent::option_definition();
    $options['type'] = array(
      'default' => 'separator',
    );
    $options['separator'] = array(
      'default' => ', ',
    );
    return $options;
  }

  /**
   * {@inheritdoc}
   */
  public function options_form(&$form, &$form_state) {
    $form['type'] = array(
      '#type' => 'radios',
      '#title' => t('Display type'),
      '#options' => array(
        'ul' => t('Unordered list'),
        'ol' => t('Ordered list'),
        'separator' => t('Simple separator'),
      ),
      '#default_value' => $this->options['type'],
    );
    $form['separator'] = array(
      '#type' => 'textfield',
      '#title' => t('Separator'),
      '#default_value' => $this->options['separator'],
      '#dependency' => array(
        'radio:options[type]' => array(
          'separator',
        ),
      ),
    );
    parent::options_form($form, $form_state);
  }

  /**
   * Render the field.
   *
   * This function is deprecated, but left in for older systems that have not
   * yet or won't update their prerender list fields. If a render_item method
   * exists, this will not get used by advanced_render.
   */
  public function render($values) {
    $field = $this
      ->get_value($values);
    if (!empty($this->items[$field])) {
      if ($this->options['type'] == 'separator') {
        return implode($this
          ->sanitize_value($this->options['separator']), $this->items[$field]);
      }
      else {
        return theme('item_list', array(
          'items' => $this->items[$field],
          'title' => NULL,
          'type' => $this->options['type'],
        ));
      }
    }
  }

  /**
   * Render all items in this field together.
   *
   * When using advanced render, each possible item in the list is rendered
   * individually. Then the items are all pasted together.
   */
  public function render_items($items) {
    if (!empty($items)) {
      if ($this->options['type'] == 'separator') {
        return implode($this
          ->sanitize_value($this->options['separator'], 'xss_admin'), $items);
      }
      else {
        return theme('item_list', array(
          'items' => $items,
          'title' => NULL,
          'type' => $this->options['type'],
        ));
      }
    }
  }

  /**
   * Return an array of items for the field.
   *
   * Items should be stored in the result array, if possible, as an array with
   * 'value' as the actual displayable value of the item, plus any items that
   * might be found in the 'alter' options array for creating links, such as
   * 'path', 'fragment', 'query' etc, such a thing is to be made. Additionally,
   * items that might be turned into tokens should also be in this array.
   *
   * @param mixed $values
   *
   * @return array
   *   The items.
   */
  public function get_items($values) {

    // Only the parent get_value returns a single field.
    $field = parent::get_value($values);
    if (!empty($this->items[$field])) {
      return $this->items[$field];
    }
    return array();
  }

  /**
   * Get the value that's supposed to be rendered.
   *
   * @param object $values
   *   An object containing all retrieved values.
   * @param string $field
   *   Optional name of the field where the value is stored.
   * @param bool $raw
   *   Use the raw data and not the data defined in pre_render
   */
  public function get_value($values, $field = NULL, $raw = FALSE) {
    if ($raw) {
      return parent::get_value($values, $field);
    }
    $item = $this
      ->get_items($values);
    $item = (array) $item;
    if (isset($field) && isset($item[$field])) {
      return $item[$field];
    }
    return $item;
  }

  /**
   * Determine if advanced rendering is allowed.
   *
   * By default, advanced rendering will NOT be allowed if the class
   * inheriting from this does not implement a 'render_items' method.
   *
   * @return bool
   *   Whether or not the the render method exists.
   */
  public function allow_advanced_render() {

    // Note that the advanced render bits also use the presence of
    // this method to determine if it needs to render items as a list.
    return method_exists($this, 'render_item');
  }

}