2.10. Registry

2.10.1. Purpose

To implement a central storage for objects often used throughout the application, is typically implemented using an abstract class with only static methods (or using the Singleton pattern)

2.10.2. Examples

  • Zend Framework 1: Zend_Registry holds the application’s logger object, front controller etc.
  • Yii Framework: CWebApplication holds all the application components, such as CWebUser, CUrlManager, etc.

2.10.3. UML Diagram

Alt Registry UML Diagram

2.10.4. Code

You can also find these code on GitHub

Registry.php

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<?php

namespace DesignPatterns\Structural\Registry;

/**
 * class Registry
 */
abstract class Registry
{
    const LOGGER = 'logger';

    /**
     * @var array
     */
    protected static $storedValues = array();

    /**
     * sets a value
     *
     * @param string $key
     * @param mixed  $value
     *
     * @static
     * @return void
     */
    public static function set($key, $value)
    {
        self::$storedValues[$key] = $value;
    }

    /**
     * gets a value from the registry
     *
     * @param string $key
     *
     * @static
     * @return mixed
     */
    public static function get($key)
    {
        return self::$storedValues[$key];
    }

    // typically there would be methods to check if a key has already been registered and so on ...
}

2.10.5. Test

Tests/RegistryTest.php

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<?php

namespace DesignPatterns\Structural\Registry\Tests;

use DesignPatterns\Structural\Registry\Registry;

class RegistryTest extends \PHPUnit_Framework_TestCase
{

    public function testSetAndGetLogger()
    {
        Registry::set(Registry::LOGGER, new \StdClass());

        $logger = Registry::get(Registry::LOGGER);
        $this->assertInstanceOf('StdClass', $logger);
    }
}