ExpressionBase.php

<?php

namespace Drupal\rules\Engine;

use Drupal\Core\Plugin\PluginBase;
use Drupal\rules\Context\ExecutionState;

/**
 * Base class for rules expressions.
 */
abstract class ExpressionBase extends PluginBase implements ExpressionInterface {
    
    /**
     * The plugin configuration.
     *
     * @var array
     */
    protected $configuration;
    
    /**
     * The root expression if this object is nested.
     *
     * @var \Drupal\rules\Engine\ExpressionInterface
     */
    protected $root;
    
    /**
     * The config entity this expression is associated with, if any.
     *
     * @var string
     */
    protected $configEntityId;
    
    /**
     * The UUID of this expression.
     *
     * @var string
     */
    protected $uuid;
    
    /**
     * The weight (list order) of this expression.
     *
     * @var int
     */
    protected $weight = 0;
    
    /**
     * Constructor.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->setConfiguration($configuration);
    }
    
    /**
     * Executes a rules expression.
     */
    public function execute() {
        // If there is no state given, we have to assume no required context.
        $state = ExecutionState::create();
        $result = $this->executeWithState($state);
        // Save specifically registered variables in the end after execution.
        $state->autoSave();
        return $result;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getConfiguration() {
        return [
            'id' => $this->getPluginId(),
            'uuid' => $this->uuid,
            'weight' => $this->weight,
        ] + $this->configuration;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setConfiguration(array $configuration) {
        $this->configuration = $configuration + $this->defaultConfiguration();
        if (isset($configuration['uuid'])) {
            $this->uuid = $configuration['uuid'];
        }
        if (isset($configuration['weight'])) {
            $this->weight = $configuration['weight'];
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function defaultConfiguration() {
        return [];
    }
    
    /**
     * {@inheritdoc}
     */
    public function calculateDependencies() {
        return [];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormHandler() {
        if (isset($this->pluginDefinition['form_class'])) {
            $class_name = $this->pluginDefinition['form_class'];
            return new $class_name($this);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function getRoot() {
        if (isset($this->root)) {
            // @todo This seems to be the parent, not root.
            return $this->root
                ->getRoot();
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setRoot(ExpressionInterface $root) {
        $this->root = $root;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getLabel() {
        return $this->pluginDefinition['label'];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getUuid() {
        return $this->uuid;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setUuid($uuid) {
        $this->uuid = $uuid;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getWeight() {
        return $this->weight;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setWeight($weight) {
        $this->weight = $weight;
        return $this;
    }

}