Event.php

<?php

abstract class CRM_Civirules_Event {

  protected $ruleId;

  protected $eventId;

  protected $eventParams;

  /**
   * @var string
   */
  protected $ruleTitle;

  public function setRuleId($ruleId) {
    $this->ruleId = $ruleId;
  }

  public function setEventParams($eventParams) {
    $this->eventParams = $eventParams;
  }

  public function getRuleId() {
    return $this->ruleId;
  }

  public function setEventId($eventId) {
    $this->eventId = $eventId;
  }

  public function getEventId() {
    return $this->eventId;
  }

  public function getRuleTitle() {
    if (empty($this->ruleTitle) && !empty($this->ruleId)) {
      $rule = new CRM_Civirules_BAO_Rule();
      $rule->id = $this->ruleId;
      if ($rule->find(true)) {
        $this->ruleTitle = $rule->label;
      }
    }
    return $this->ruleTitle;
  }

  /**
   * Returns an array of entities on which the event reacts
   *
   * @return CRM_Civirules_EventData_EntityDefinition
   */
  abstract protected function reactOnEntity();


  public function getProvidedEntities() {
    $additionalEntities = $this->getAdditionalEntities();
    foreach($additionalEntities as $entity) {
      $entities[$entity->key] = $entity;
    }

    $entity = $this->reactOnEntity();
    $entities[$entity->key] = $entity;

    return $entities;
  }

  /**
   * Returns an array of additional entities provided in this event
   *
   * @return array of CRM_Civirules_EventData_EntityDefinition
   */
  protected function getAdditionalEntities() {
    return array();
  }

  /**
   * Returns a redirect url to extra data input from the user after adding a condition
   *
   * Return false if you do not need extra data input
   *
   * @param int $ruleId
   * @return bool|string
   * @access public
   * @abstract
   */
  public function getExtraDataInputUrl($ruleId) {
    return false;
  }

  /**
   * Returns a description of this event
   *
   * @return string
   * @access public
   * @abstract
   */
  public function getEventDescription() {
    return '';
  }

}