3 * A registry for several data types and objects. Objects should be added by
4 * addInstance() and therefore must implement the interface Registerable.
6 * @author Roland Haeder <webmaster@ship-simu.org>
8 * @copyright Copyright (c) 2007, 2008 Roland Haeder, 2009, 2010 Core Developer Team
9 * @license GNU GPL 3.0 or any newer version
10 * @link http://www.ship-simu.org
12 * This program is free software: you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation, either version 3 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program. If not, see <http://www.gnu.org/licenses/>.
25 class Registry extends BaseFrameworkSystem implements Register {
27 * Instance of this class
29 private static $registryInstance = null;
34 private $instanceRegistry = array();
37 * Protected constructor
41 protected function __construct () {
42 // Call parent constructor
43 parent::__construct(__CLASS__);
47 * Singleton getter for self instance. This class has no factory pattern
48 * because here is no need for special parameters.
50 * @return $registryInstance Instance of this class
52 public final static function getRegistry () {
53 // Is an instance there?
54 if (is_null(self::$registryInstance)) {
55 // Not yet, so create one
56 self::$registryInstance = new Registry();
59 // Return the instance
60 return self::$registryInstance;
64 * Checks wether an instance key was found
66 * @param $instanceKey The key holding an instance in registry
67 * @return $exists Wether the key exists in registry
69 public function instanceExists ($instanceKey) {
70 // Does this key exists?
71 $exists = (isset($this->instanceRegistry[$instanceKey]));
78 * Adds/overwrites a new instance to the registry at the given key
80 * @param $instanceKey The key to identify the instance
81 * @param $objectInstance An instance we shall store
84 public function addInstance ($instanceKey, Registerable $objectInstance) {
85 $this->instanceRegistry[$instanceKey] = $objectInstance;
89 * Gets a registered instance or null if not found
91 * @param $instanceKey The key to identify the instance
92 * @return $objectInstance An instance we shall store
93 * @throws NullPointerException If the requested key is not found
95 public function getInstance ($instanceKey) {
96 // By default the instance is not in registry
97 $objectInstance = null;
99 // Is the instance there?
100 if ($this->instanceExists($instanceKey)) {
101 $objectInstance = $this->instanceRegistry[$instanceKey];
104 // Still not fetched?
105 if (is_null($objectInstance)) {
106 // This might happen if a non-registered key was requested
107 throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
111 return $objectInstance;