rules-8.x-3.x-dev/src/Engine/ExpressionContainerInterface.php

<?php

namespace Drupal\rules\Engine;

use Drupal\rules\Context\ContextConfig;

/**
 * Defines a common interface for expressions containing other expressions.
 *
 * Usually expression containers also implement the
 * ActionExpressionContainerInterface or ConditionExpressionContainerInterface
 * in order to denote whether it contains action or condition expressions.
 */
interface ExpressionContainerInterface extends ExpressionInterface, \IteratorAggregate {

  /**
   * Creates and adds an expression.
   *
   * @param string $plugin_id
   *   The id of the expression plugin to add.
   * @param \Drupal\rules\Context\ContextConfig|null $config
   *   (optional) The configuration for the specified plugin.
   *
   * @throws \Drupal\rules\Exception\InvalidExpressionException
   *   Thrown if the wrong expression is passed; e.g. if a condition expression
   *   is added to an action expression container.
   *
   * @return $this
   */
  public function addExpression(string $plugin_id, ?ContextConfig $config = NULL);

  /**
   * Adds an expression object.
   *
   * @param \Drupal\rules\Engine\ExpressionInterface $expression
   *   The expression object.
   *
   * @throws \Drupal\rules\Exception\InvalidExpressionException
   *   Thrown if the wrong expression is passed; e.g. if a condition expression
   *   is added to an action expression container.
   *
   * @return $this
   */
  public function addExpressionObject(ExpressionInterface $expression);

  /**
   * Looks up the expression by UUID in this container.
   *
   * @param string $uuid
   *   The UUID of the expression.
   *
   * @return \Drupal\rules\Engine\ExpressionInterface|false
   *   The expression object or FALSE if not expression object with that UUID
   *   could be found.
   */
  public function getExpression($uuid);

  /**
   * Deletes an expression identified by the specified UUID in the container.
   *
   * @param string $uuid
   *   The UUID of the expression.
   *
   * @return bool
   *   TRUE if an expression was deleted, FALSE if no expression with that UUID
   *   was found.
   */
  public function deleteExpression($uuid);

  /**
   * Returns an iterator for expressions in this container.
   *
   * @return \Traversable
   *   An object that may be iterated with "foreach".
   */
  public function getIterator(): \Traversable;

}