PublisherSubscriberManager.php

<?php
/**
 * Copyright 2014 Openstack Foundation
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/

/**
 * Class PublisherSubscriberManager
 */
final class PublisherSubscriberManager
{
    /**
     * @var PublisherSubscriberManager
     */
    private static $instance;

    private $events = []; // all subscriptions

    private function __construct(){}

    private function __clone(){}

    /**
     * @return PublisherSubscriberManager
     */
    public static function getInstance()
    {
        if (!is_object(self::$instance)) {
            self::$instance = new PublisherSubscriberManager();
        }

        return self::$instance;
    }

    /**
     * @param string $event_name
     * @param $callback
     */
    public function subscribe($event_name, $callback)
    {

        // Make sure the subscription isn't null
        if (empty($this->events[$event_name])) {
            $this->events[$event_name] = array();
        }
        // push the $callback onto the subscription stack
        array_push($this->events[$event_name], $callback);
    }

    /**
     * @param string $event_name
     * @param array $params
     * @return bool
     */
    public function publish($event_name, array $params = array())
    {
        // Check to see if the subscribe isn't null
        if (empty($this->events[$event_name])) {
            return false;
        }

        // Loop through all the events and call them
        // call it inside tx
        foreach ($this->events[$event_name] as $event) {
            if (is_callable($event)) {
                SapphireTransactionManager::getInstance()->transaction(function() use($event, $params) {
                    call_user_func_array($event, $params);
                });
            }
        }
    }

    /**
     * @param string $event_name
     */
    public function unsubscribe($event_name)
    {
        if (!empty($this->events[$event_name])) {
            unset($this->events[$event_name]);
        }
    }

}