eventespresso / event-espresso-core

core/EE_Dependency_Map.core.php

Indentation +575 added lines, -575 removed lines

@@ -4,7 +4,7 @@ 
 use EventEspresso\core\services\loaders\LoaderInterface;
 
 if (! defined('EVENT_ESPRESSO_VERSION')) {
-    exit('No direct script access allowed');
+	exit('No direct script access allowed');
 }
 
 
@@ -22,580 +22,580 @@ 
 {
 
 
-    /**
-     * This means that the requested class dependency is not present in the dependency map
-     */
-    const not_registered = 0;
-
-
-    /**
-     * This instructs class loaders to ALWAYS return a newly instantiated object for the requested class.
-     */
-    const load_new_object = 1;
-
-    /**
-     * This instructs class loaders to return a previously instantiated and cached object for the requested class.
-     * IF a previously instantiated object does not exist, a new one will be created and added to the cache.
-     */
-    const load_from_cache = 2;
-
-    /**
-     * @type EE_Dependency_Map $_instance
-     */
-    protected static $_instance;
-
-    /**
-     * @type EE_Request $request
-     */
-    protected $_request;
-
-    /**
-     * @type EE_Response $response
-     */
-    protected $_response;
-
-    /**
-     * @type LoaderInterface $loader
-     */
-    protected $loader;
-
-    /**
-     * @type array $_dependency_map
-     */
-    protected $_dependency_map = array();
-
-    /**
-     * @type array $_class_loaders
-     */
-    protected $_class_loaders = array();
-
-    /**
-     * @type array $_aliases
-     */
-    protected $_aliases = array();
-
-
-
-    /**
-     * EE_Dependency_Map constructor.
-     *
-     * @param EE_Request  $request
-     * @param EE_Response $response
-     */
-    protected function __construct(EE_Request $request, EE_Response $response)
-    {
-        $this->_request = $request;
-        $this->_response = $response;
-        add_action('EE_Load_Espresso_Core__handle_request__initialize_core_loading', array($this, 'initialize'));
-        do_action('EE_Dependency_Map____construct');
-    }
-
-
-
-    /**
-     * @throws InvalidDataTypeException
-     * @throws InvalidInterfaceException
-     * @throws InvalidArgumentException
-     */
-    public function initialize()
-    {
-        $this->_register_core_dependencies();
-        $this->_register_core_class_loaders();
-        $this->_register_core_aliases();
-    }
-
-
-
-    /**
-     * @singleton method used to instantiate class object
-     * @access    public
-     * @param EE_Request  $request
-     * @param EE_Response $response
-     * @return EE_Dependency_Map
-     */
-    public static function instance(EE_Request $request = null, EE_Response $response = null)
-    {
-        // check if class object is instantiated, and instantiated properly
-        if (! self::$_instance instanceof EE_Dependency_Map) {
-            self::$_instance = new EE_Dependency_Map($request, $response);
-        }
-        return self::$_instance;
-    }
-
-
-
-    /**
-     * @param LoaderInterface $loader
-     */
-    public function setLoader(LoaderInterface $loader)
-    {
-        $this->loader = $loader;
-    }
-
-
-
-    /**
-     * @param string $class
-     * @param array  $dependencies
-     * @return boolean
-     */
-    public static function register_dependencies($class, $dependencies)
-    {
-        if (! isset(self::$_instance->_dependency_map[$class])) {
-            // we need to make sure that any aliases used when registering a dependency
-            // get resolved to the correct class name
-            foreach ((array)$dependencies as $dependency => $load_source) {
-                $alias = self::$_instance->get_alias($dependency);
-                unset($dependencies[$dependency]);
-                $dependencies[$alias] = $load_source;
-            }
-            self::$_instance->_dependency_map[$class] = (array)$dependencies;
-            return true;
-        }
-        return false;
-    }
-
-
-
-    /**
-     * @param string $class_name
-     * @param string $loader
-     * @return bool
-     * @throws EE_Error
-     */
-    public static function register_class_loader($class_name, $loader = 'load_core')
-    {
-        // check that loader is callable or method starts with "load_" and exists in EE_Registry
-        if (
-            ! is_callable($loader)
-            && (
-                strpos($loader, 'load_') !== 0
-                || ! method_exists('EE_Registry', $loader)
-            )
-        ) {
-            throw new EE_Error(
-                sprintf(
-                    __('"%1$s" is not a valid loader method on EE_Registry.', 'event_espresso'),
-                    $loader
-                )
-            );
-        }
-        $class_name = self::$_instance->get_alias($class_name);
-        if (! isset(self::$_instance->_class_loaders[$class_name])) {
-            self::$_instance->_class_loaders[$class_name] = $loader;
-            return true;
-        }
-        return false;
-    }
-
-
-
-    /**
-     * @return array
-     */
-    public function dependency_map()
-    {
-        return $this->_dependency_map;
-    }
-
-
-
-    /**
-     * returns TRUE if dependency map contains a listing for the provided class name
-     *
-     * @param string $class_name
-     * @return boolean
-     */
-    public function has($class_name = '')
-    {
-        return isset($this->_dependency_map[$class_name]) ? true : false;
-    }
-
-
-
-    /**
-     * returns TRUE if dependency map contains a listing for the provided class name AND dependency
-     *
-     * @param string $class_name
-     * @param string $dependency
-     * @return bool
-     */
-    public function has_dependency_for_class($class_name = '', $dependency = '')
-    {
-        $dependency = $this->get_alias($dependency);
-        return isset($this->_dependency_map[$class_name], $this->_dependency_map[$class_name][$dependency])
-            ? true
-            : false;
-    }
-
-
-
-    /**
-     * returns loading strategy for whether a previously cached dependency should be loaded or a new instance returned
-     *
-     * @param string $class_name
-     * @param string $dependency
-     * @return int
-     */
-    public function loading_strategy_for_class_dependency($class_name = '', $dependency = '')
-    {
-        $dependency = $this->get_alias($dependency);
-        return $this->has_dependency_for_class($class_name, $dependency)
-            ? $this->_dependency_map[$class_name][$dependency]
-            : EE_Dependency_Map::not_registered;
-    }
-
-
-
-    /**
-     * @param string $class_name
-     * @return string | Closure
-     */
-    public function class_loader($class_name)
-    {
-        $class_name = $this->get_alias($class_name);
-        return isset($this->_class_loaders[$class_name]) ? $this->_class_loaders[$class_name] : '';
-    }
-
-
-
-    /**
-     * @return array
-     */
-    public function class_loaders()
-    {
-        return $this->_class_loaders;
-    }
-
-
-
-    /**
-     * adds an alias for a classname
-     *
-     * @param string $class_name
-     * @param string $alias
-     */
-    public function add_alias($class_name, $alias)
-    {
-        $this->_aliases[$class_name] = $alias;
-    }
-
-
-
-    /**
-     * returns TRUE if the provided class name has an alias
-     *
-     * @param string $class_name
-     * @return boolean
-     */
-    public function has_alias($class_name = '')
-    {
-        return isset($this->_aliases[$class_name]) ? true : false;
-    }
-
-
-
-    /**
-     * returns alias for class name if one exists, otherwise returns the original classname
-     * functions recursively, so that multiple aliases can be used to drill down to a classname
-     *  for example:
-     *      if the following two entries were added to the _aliases array:
-     *          array(
-     *              'interface_alias'           => 'some\namespace\interface'
-     *              'some\namespace\interface'  => 'some\namespace\classname'
-     *          )
-     *      then one could use EE_Registry::instance()->create( 'interface_alias' )
-     *      to load an instance of 'some\namespace\classname'
-     *
-     * @param string $class_name
-     * @return string
-     */
-    public function get_alias($class_name = '')
-    {
-        return $this->has_alias($class_name)
-            ? $this->get_alias($this->_aliases[$class_name])
-            : $class_name;
-    }
-
-
-
-    /**
-     * Registers the core dependencies and whether a previously instantiated object should be loaded from the cache,
-     * if one exists, or whether a new object should be generated every time the requested class is loaded.
-     * This is done by using the following class constants:
-     *        EE_Dependency_Map::load_from_cache - loads previously instantiated object
-     *        EE_Dependency_Map::load_new_object - generates a new object every time
-     */
-    protected function _register_core_dependencies()
-    {
-        $this->_dependency_map = array(
-            'EE_Request_Handler'                                                                                          => array(
-                'EE_Request' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_System'                                                                                                   => array(
-                'EE_Registry' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Session'                                                                                                  => array(
-                'EE_Encryption' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Cart'                                                                                                     => array(
-                'EE_Session' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Front_Controller'                                                                                         => array(
-                'EE_Registry'              => EE_Dependency_Map::load_from_cache,
-                'EE_Request_Handler'       => EE_Dependency_Map::load_from_cache,
-                'EE_Module_Request_Router' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Messenger_Collection_Loader'                                                                              => array(
-                'EE_Messenger_Collection' => EE_Dependency_Map::load_new_object,
-            ),
-            'EE_Message_Type_Collection_Loader'                                                                           => array(
-                'EE_Message_Type_Collection' => EE_Dependency_Map::load_new_object,
-            ),
-            'EE_Message_Resource_Manager'                                                                                 => array(
-                'EE_Messenger_Collection_Loader'    => EE_Dependency_Map::load_new_object,
-                'EE_Message_Type_Collection_Loader' => EE_Dependency_Map::load_new_object,
-                'EEM_Message_Template_Group'        => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Message_Factory'                                                                                          => array(
-                'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_messages'                                                                                                 => array(
-                'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Messages_Generator'                                                                                       => array(
-                'EE_Messages_Queue'                    => EE_Dependency_Map::load_new_object,
-                'EE_Messages_Data_Handler_Collection'  => EE_Dependency_Map::load_new_object,
-                'EE_Message_Template_Group_Collection' => EE_Dependency_Map::load_new_object,
-                'EEH_Parse_Shortcodes'                 => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Messages_Processor'                                                                                       => array(
-                'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Messages_Queue'                                                                                           => array(
-                'EE_Message_Repository' => EE_Dependency_Map::load_new_object,
-            ),
-            'EE_Messages_Template_Defaults'                                                                               => array(
-                'EEM_Message_Template_Group' => EE_Dependency_Map::load_from_cache,
-                'EEM_Message_Template'       => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Message_To_Generate_From_Request'                                                                         => array(
-                'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
-                'EE_Request_Handler'          => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\CommandBus'                                                             => array(
-                'EventEspresso\core\services\commands\CommandHandlerManager' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\CommandHandlerManager'                                                  => array(
-                'EventEspresso\core\services\loaders\Loader' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\CompositeCommandHandler'                                                              => array(
-                'EventEspresso\core\services\commands\CommandBus'     => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\commands\CommandFactory' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\CommandFactory'                                                              => array(
-                'EventEspresso\core\services\loaders\Loader' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\middleware\CapChecker'                                                  => array(
-                'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker'                                         => array(
-                'EE_Capabilities' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\domain\services\capabilities\RegistrationsCapChecker'                                     => array(
-                'EE_Capabilities' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\registration\CreateRegistrationCommandHandler'                          => array(
-                'EventEspresso\core\domain\services\registration\CreateRegistrationService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\registration\CopyRegistrationDetailsCommandHandler'                     => array(
-                'EventEspresso\core\domain\services\registration\CopyRegistrationService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\registration\CopyRegistrationPaymentsCommandHandler'                    => array(
-                'EventEspresso\core\domain\services\registration\CopyRegistrationService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\registration\CancelRegistrationAndTicketLineItemCommandHandler'         => array(
-                'EventEspresso\core\domain\services\registration\CancelTicketLineItemService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\registration\UpdateRegistrationAndTransactionAfterChangeCommandHandler' => array(
-                'EventEspresso\core\domain\services\registration\UpdateRegistrationService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\ticket\CreateTicketLineItemCommandHandler'                              => array(
-                'EventEspresso\core\domain\services\ticket\CreateTicketLineItemService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\commands\ticket\CancelTicketLineItemCommandHandler'                              => array(
-                'EventEspresso\core\domain\services\ticket\CancelTicketLineItemService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\domain\services\registration\CancelRegistrationService'                                   => array(
-                'EventEspresso\core\domain\services\ticket\CancelTicketLineItemService' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EventEspresso\core\services\database\TableManager'                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_Data_Migration_Class_Base'                                                                                => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_1_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_2_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_3_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_4_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_5_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_6_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_7_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_8_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-            'EE_DMS_Core_4_9_0'                                                                                           => array(
-                'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
-                'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
-            ),
-        );
-    }
-
-
-
-    /**
-     * Registers how core classes are loaded.
-     * This can either be done by simply providing the name of one of the EE_Registry loader methods such as:
-     *        'EE_Request_Handler' => 'load_core'
-     *        'EE_Messages_Queue'  => 'load_lib'
-     *        'EEH_Debug_Tools'    => 'load_helper'
-     * or, if greater control is required, by providing a custom closure. For example:
-     *        'Some_Class' => function () {
-     *            return new Some_Class();
-     *        },
-     * This is required for instantiating dependencies
-     * where an interface has been type hinted in a class constructor. For example:
-     *        'Required_Interface' => function () {
-     *            return new A_Class_That_Implements_Required_Interface();
-     *        },
-     */
-    protected function _register_core_class_loaders()
-    {
-        //for PHP5.3 compat, we need to register any properties called here in a variable because `$this` cannot
-        //be used in a closure.
-        $request = &$this->_request;
-        $response = &$this->_response;
-        $loader = &$this->loader;
-        $this->_class_loaders = array(
-            //load_core
-            'EE_Capabilities'                      => 'load_core',
-            'EE_Encryption'                        => 'load_core',
-            'EE_Front_Controller'                  => 'load_core',
-            'EE_Module_Request_Router'             => 'load_core',
-            'EE_Registry'                          => 'load_core',
-            'EE_Request'                           => function () use (&$request) {
-                return $request;
-            },
-            'EE_Response'                          => function () use (&$response) {
-                return $response;
-            },
-            'EE_Request_Handler'                   => 'load_core',
-            'EE_Session'                           => 'load_core',
-            'EE_System'                            => 'load_core',
-            //load_lib
-            'EE_Message_Resource_Manager'          => 'load_lib',
-            'EE_Message_Type_Collection'           => 'load_lib',
-            'EE_Message_Type_Collection_Loader'    => 'load_lib',
-            'EE_Messenger_Collection'              => 'load_lib',
-            'EE_Messenger_Collection_Loader'       => 'load_lib',
-            'EE_Messages_Processor'                => 'load_lib',
-            'EE_Message_Repository'                => 'load_lib',
-            'EE_Messages_Queue'                    => 'load_lib',
-            'EE_Messages_Data_Handler_Collection'  => 'load_lib',
-            'EE_Message_Template_Group_Collection' => 'load_lib',
-            'EE_Messages_Generator'                => function () {
-                return EE_Registry::instance()->load_lib('Messages_Generator', array(), false, false);
-            },
-            'EE_Messages_Template_Defaults'        => function ($arguments = array()) {
-                return EE_Registry::instance()->load_lib('Messages_Template_Defaults', $arguments, false, false);
-            },
-            //load_model
-            'EEM_Message_Template_Group'           => 'load_model',
-            'EEM_Message_Template'                 => 'load_model',
-            //load_helper
-            'EEH_Parse_Shortcodes'                 => function () {
-                if (EE_Registry::instance()->load_helper('Parse_Shortcodes')) {
-                    return new EEH_Parse_Shortcodes();
-                }
-                return null;
-            },
-            'EventEspresso\core\services\loaders\Loader' => function () use (&$loader) {
-                return $loader;
-            },
-        );
-    }
-
-
-
-    /**
-     * can be used for supplying alternate names for classes,
-     * or for connecting interface names to instantiable classes
-     */
-    protected function _register_core_aliases()
-    {
-        $this->_aliases = array(
-            'CommandBusInterface'                                                 => 'EventEspresso\core\services\commands\CommandBusInterface',
-            'EventEspresso\core\services\commands\CommandBusInterface'            => 'EventEspresso\core\services\commands\CommandBus',
-            'CommandHandlerManagerInterface'                                      => 'EventEspresso\core\services\commands\CommandHandlerManagerInterface',
-            'EventEspresso\core\services\commands\CommandHandlerManagerInterface' => 'EventEspresso\core\services\commands\CommandHandlerManager',
-            'CapChecker'                                                          => 'EventEspresso\core\services\commands\middleware\CapChecker',
-            'AddActionHook'                                                       => 'EventEspresso\core\services\commands\middleware\AddActionHook',
-            'CapabilitiesChecker'                                                 => 'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker',
-            'CapabilitiesCheckerInterface'                                        => 'EventEspresso\core\domain\services\capabilities\CapabilitiesCheckerInterface',
-            'EventEspresso\core\domain\services\capabilities\CapabilitiesCheckerInterface' => 'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker',
-            'CreateRegistrationService'                                           => 'EventEspresso\core\domain\services\registration\CreateRegistrationService',
-            'CreateRegCodeCommandHandler'                                         => 'EventEspresso\core\services\commands\registration\CreateRegCodeCommand',
-            'CreateRegUrlLinkCommandHandler'                                      => 'EventEspresso\core\services\commands\registration\CreateRegUrlLinkCommand',
-            'CreateRegistrationCommandHandler'                                    => 'EventEspresso\core\services\commands\registration\CreateRegistrationCommand',
-            'CopyRegistrationDetailsCommandHandler'                               => 'EventEspresso\core\services\commands\registration\CopyRegistrationDetailsCommand',
-            'CopyRegistrationPaymentsCommandHandler'                              => 'EventEspresso\core\services\commands\registration\CopyRegistrationPaymentsCommand',
-            'CancelRegistrationAndTicketLineItemCommandHandler'                   => 'EventEspresso\core\services\commands\registration\CancelRegistrationAndTicketLineItemCommandHandler',
-            'UpdateRegistrationAndTransactionAfterChangeCommandHandler'           => 'EventEspresso\core\services\commands\registration\UpdateRegistrationAndTransactionAfterChangeCommandHandler',
-            'CreateTicketLineItemCommandHandler'                                  => 'EventEspresso\core\services\commands\ticket\CreateTicketLineItemCommand',
-            'TableManager'                                                        => 'EventEspresso\core\services\database\TableManager',
-            'TableAnalysis'                                                       => 'EventEspresso\core\services\database\TableAnalysis',
-            'LoaderInterface'                                                     => 'EventEspresso\core\services\loaders\LoaderInterface',
-            'EventEspresso\core\services\loaders\LoaderInterface'                 => 'EventEspresso\core\services\loaders\Loader',
-            'CommandFactoryInterface'                                             => 'EventEspresso\core\services\commands\CommandFactoryInterface',
-            'EventEspresso\core\services\commands\CommandFactoryInterface'        => 'EventEspresso\core\services\commands\CommandFactory',
-        );
-    }
-
-
-
-    /**
-     * This is used to reset the internal map and class_loaders to their original default state at the beginning of the
-     * request Primarily used by unit tests.
-     */
-    public function reset()
-    {
-        $this->_register_core_class_loaders();
-        $this->_register_core_dependencies();
-    }
+	/**
+	 * This means that the requested class dependency is not present in the dependency map
+	 */
+	const not_registered = 0;
+
+
+	/**
+	 * This instructs class loaders to ALWAYS return a newly instantiated object for the requested class.
+	 */
+	const load_new_object = 1;
+
+	/**
+	 * This instructs class loaders to return a previously instantiated and cached object for the requested class.
+	 * IF a previously instantiated object does not exist, a new one will be created and added to the cache.
+	 */
+	const load_from_cache = 2;
+
+	/**
+	 * @type EE_Dependency_Map $_instance
+	 */
+	protected static $_instance;
+
+	/**
+	 * @type EE_Request $request
+	 */
+	protected $_request;
+
+	/**
+	 * @type EE_Response $response
+	 */
+	protected $_response;
+
+	/**
+	 * @type LoaderInterface $loader
+	 */
+	protected $loader;
+
+	/**
+	 * @type array $_dependency_map
+	 */
+	protected $_dependency_map = array();
+
+	/**
+	 * @type array $_class_loaders
+	 */
+	protected $_class_loaders = array();
+
+	/**
+	 * @type array $_aliases
+	 */
+	protected $_aliases = array();
+
+
+
+	/**
+	 * EE_Dependency_Map constructor.
+	 *
+	 * @param EE_Request  $request
+	 * @param EE_Response $response
+	 */
+	protected function __construct(EE_Request $request, EE_Response $response)
+	{
+		$this->_request = $request;
+		$this->_response = $response;
+		add_action('EE_Load_Espresso_Core__handle_request__initialize_core_loading', array($this, 'initialize'));
+		do_action('EE_Dependency_Map____construct');
+	}
+
+
+
+	/**
+	 * @throws InvalidDataTypeException
+	 * @throws InvalidInterfaceException
+	 * @throws InvalidArgumentException
+	 */
+	public function initialize()
+	{
+		$this->_register_core_dependencies();
+		$this->_register_core_class_loaders();
+		$this->_register_core_aliases();
+	}
+
+
+
+	/**
+	 * @singleton method used to instantiate class object
+	 * @access    public
+	 * @param EE_Request  $request
+	 * @param EE_Response $response
+	 * @return EE_Dependency_Map
+	 */
+	public static function instance(EE_Request $request = null, EE_Response $response = null)
+	{
+		// check if class object is instantiated, and instantiated properly
+		if (! self::$_instance instanceof EE_Dependency_Map) {
+			self::$_instance = new EE_Dependency_Map($request, $response);
+		}
+		return self::$_instance;
+	}
+
+
+
+	/**
+	 * @param LoaderInterface $loader
+	 */
+	public function setLoader(LoaderInterface $loader)
+	{
+		$this->loader = $loader;
+	}
+
+
+
+	/**
+	 * @param string $class
+	 * @param array  $dependencies
+	 * @return boolean
+	 */
+	public static function register_dependencies($class, $dependencies)
+	{
+		if (! isset(self::$_instance->_dependency_map[$class])) {
+			// we need to make sure that any aliases used when registering a dependency
+			// get resolved to the correct class name
+			foreach ((array)$dependencies as $dependency => $load_source) {
+				$alias = self::$_instance->get_alias($dependency);
+				unset($dependencies[$dependency]);
+				$dependencies[$alias] = $load_source;
+			}
+			self::$_instance->_dependency_map[$class] = (array)$dependencies;
+			return true;
+		}
+		return false;
+	}
+
+
+
+	/**
+	 * @param string $class_name
+	 * @param string $loader
+	 * @return bool
+	 * @throws EE_Error
+	 */
+	public static function register_class_loader($class_name, $loader = 'load_core')
+	{
+		// check that loader is callable or method starts with "load_" and exists in EE_Registry
+		if (
+			! is_callable($loader)
+			&& (
+				strpos($loader, 'load_') !== 0
+				|| ! method_exists('EE_Registry', $loader)
+			)
+		) {
+			throw new EE_Error(
+				sprintf(
+					__('"%1$s" is not a valid loader method on EE_Registry.', 'event_espresso'),
+					$loader
+				)
+			);
+		}
+		$class_name = self::$_instance->get_alias($class_name);
+		if (! isset(self::$_instance->_class_loaders[$class_name])) {
+			self::$_instance->_class_loaders[$class_name] = $loader;
+			return true;
+		}
+		return false;
+	}
+
+
+
+	/**
+	 * @return array
+	 */
+	public function dependency_map()
+	{
+		return $this->_dependency_map;
+	}
+
+
+
+	/**
+	 * returns TRUE if dependency map contains a listing for the provided class name
+	 *
+	 * @param string $class_name
+	 * @return boolean
+	 */
+	public function has($class_name = '')
+	{
+		return isset($this->_dependency_map[$class_name]) ? true : false;
+	}
+
+
+
+	/**
+	 * returns TRUE if dependency map contains a listing for the provided class name AND dependency
+	 *
+	 * @param string $class_name
+	 * @param string $dependency
+	 * @return bool
+	 */
+	public function has_dependency_for_class($class_name = '', $dependency = '')
+	{
+		$dependency = $this->get_alias($dependency);
+		return isset($this->_dependency_map[$class_name], $this->_dependency_map[$class_name][$dependency])
+			? true
+			: false;
+	}
+
+
+
+	/**
+	 * returns loading strategy for whether a previously cached dependency should be loaded or a new instance returned
+	 *
+	 * @param string $class_name
+	 * @param string $dependency
+	 * @return int
+	 */
+	public function loading_strategy_for_class_dependency($class_name = '', $dependency = '')
+	{
+		$dependency = $this->get_alias($dependency);
+		return $this->has_dependency_for_class($class_name, $dependency)
+			? $this->_dependency_map[$class_name][$dependency]
+			: EE_Dependency_Map::not_registered;
+	}
+
+
+
+	/**
+	 * @param string $class_name
+	 * @return string | Closure
+	 */
+	public function class_loader($class_name)
+	{
+		$class_name = $this->get_alias($class_name);
+		return isset($this->_class_loaders[$class_name]) ? $this->_class_loaders[$class_name] : '';
+	}
+
+
+
+	/**
+	 * @return array
+	 */
+	public function class_loaders()
+	{
+		return $this->_class_loaders;
+	}
+
+
+
+	/**
+	 * adds an alias for a classname
+	 *
+	 * @param string $class_name
+	 * @param string $alias
+	 */
+	public function add_alias($class_name, $alias)
+	{
+		$this->_aliases[$class_name] = $alias;
+	}
+
+
+
+	/**
+	 * returns TRUE if the provided class name has an alias
+	 *
+	 * @param string $class_name
+	 * @return boolean
+	 */
+	public function has_alias($class_name = '')
+	{
+		return isset($this->_aliases[$class_name]) ? true : false;
+	}
+
+
+
+	/**
+	 * returns alias for class name if one exists, otherwise returns the original classname
+	 * functions recursively, so that multiple aliases can be used to drill down to a classname
+	 *  for example:
+	 *      if the following two entries were added to the _aliases array:
+	 *          array(
+	 *              'interface_alias'           => 'some\namespace\interface'
+	 *              'some\namespace\interface'  => 'some\namespace\classname'
+	 *          )
+	 *      then one could use EE_Registry::instance()->create( 'interface_alias' )
+	 *      to load an instance of 'some\namespace\classname'
+	 *
+	 * @param string $class_name
+	 * @return string
+	 */
+	public function get_alias($class_name = '')
+	{
+		return $this->has_alias($class_name)
+			? $this->get_alias($this->_aliases[$class_name])
+			: $class_name;
+	}
+
+
+
+	/**
+	 * Registers the core dependencies and whether a previously instantiated object should be loaded from the cache,
+	 * if one exists, or whether a new object should be generated every time the requested class is loaded.
+	 * This is done by using the following class constants:
+	 *        EE_Dependency_Map::load_from_cache - loads previously instantiated object
+	 *        EE_Dependency_Map::load_new_object - generates a new object every time
+	 */
+	protected function _register_core_dependencies()
+	{
+		$this->_dependency_map = array(
+			'EE_Request_Handler'                                                                                          => array(
+				'EE_Request' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_System'                                                                                                   => array(
+				'EE_Registry' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Session'                                                                                                  => array(
+				'EE_Encryption' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Cart'                                                                                                     => array(
+				'EE_Session' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Front_Controller'                                                                                         => array(
+				'EE_Registry'              => EE_Dependency_Map::load_from_cache,
+				'EE_Request_Handler'       => EE_Dependency_Map::load_from_cache,
+				'EE_Module_Request_Router' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Messenger_Collection_Loader'                                                                              => array(
+				'EE_Messenger_Collection' => EE_Dependency_Map::load_new_object,
+			),
+			'EE_Message_Type_Collection_Loader'                                                                           => array(
+				'EE_Message_Type_Collection' => EE_Dependency_Map::load_new_object,
+			),
+			'EE_Message_Resource_Manager'                                                                                 => array(
+				'EE_Messenger_Collection_Loader'    => EE_Dependency_Map::load_new_object,
+				'EE_Message_Type_Collection_Loader' => EE_Dependency_Map::load_new_object,
+				'EEM_Message_Template_Group'        => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Message_Factory'                                                                                          => array(
+				'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_messages'                                                                                                 => array(
+				'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Messages_Generator'                                                                                       => array(
+				'EE_Messages_Queue'                    => EE_Dependency_Map::load_new_object,
+				'EE_Messages_Data_Handler_Collection'  => EE_Dependency_Map::load_new_object,
+				'EE_Message_Template_Group_Collection' => EE_Dependency_Map::load_new_object,
+				'EEH_Parse_Shortcodes'                 => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Messages_Processor'                                                                                       => array(
+				'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Messages_Queue'                                                                                           => array(
+				'EE_Message_Repository' => EE_Dependency_Map::load_new_object,
+			),
+			'EE_Messages_Template_Defaults'                                                                               => array(
+				'EEM_Message_Template_Group' => EE_Dependency_Map::load_from_cache,
+				'EEM_Message_Template'       => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Message_To_Generate_From_Request'                                                                         => array(
+				'EE_Message_Resource_Manager' => EE_Dependency_Map::load_from_cache,
+				'EE_Request_Handler'          => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\CommandBus'                                                             => array(
+				'EventEspresso\core\services\commands\CommandHandlerManager' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\CommandHandlerManager'                                                  => array(
+				'EventEspresso\core\services\loaders\Loader' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\CompositeCommandHandler'                                                              => array(
+				'EventEspresso\core\services\commands\CommandBus'     => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\commands\CommandFactory' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\CommandFactory'                                                              => array(
+				'EventEspresso\core\services\loaders\Loader' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\middleware\CapChecker'                                                  => array(
+				'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker'                                         => array(
+				'EE_Capabilities' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\domain\services\capabilities\RegistrationsCapChecker'                                     => array(
+				'EE_Capabilities' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\registration\CreateRegistrationCommandHandler'                          => array(
+				'EventEspresso\core\domain\services\registration\CreateRegistrationService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\registration\CopyRegistrationDetailsCommandHandler'                     => array(
+				'EventEspresso\core\domain\services\registration\CopyRegistrationService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\registration\CopyRegistrationPaymentsCommandHandler'                    => array(
+				'EventEspresso\core\domain\services\registration\CopyRegistrationService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\registration\CancelRegistrationAndTicketLineItemCommandHandler'         => array(
+				'EventEspresso\core\domain\services\registration\CancelTicketLineItemService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\registration\UpdateRegistrationAndTransactionAfterChangeCommandHandler' => array(
+				'EventEspresso\core\domain\services\registration\UpdateRegistrationService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\ticket\CreateTicketLineItemCommandHandler'                              => array(
+				'EventEspresso\core\domain\services\ticket\CreateTicketLineItemService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\commands\ticket\CancelTicketLineItemCommandHandler'                              => array(
+				'EventEspresso\core\domain\services\ticket\CancelTicketLineItemService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\domain\services\registration\CancelRegistrationService'                                   => array(
+				'EventEspresso\core\domain\services\ticket\CancelTicketLineItemService' => EE_Dependency_Map::load_from_cache,
+			),
+			'EventEspresso\core\services\database\TableManager'                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_Data_Migration_Class_Base'                                                                                => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_1_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_2_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_3_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_4_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_5_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_6_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_7_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_8_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+			'EE_DMS_Core_4_9_0'                                                                                           => array(
+				'EventEspresso\core\services\database\TableAnalysis' => EE_Dependency_Map::load_from_cache,
+				'EventEspresso\core\services\database\TableManager'  => EE_Dependency_Map::load_from_cache,
+			),
+		);
+	}
+
+
+
+	/**
+	 * Registers how core classes are loaded.
+	 * This can either be done by simply providing the name of one of the EE_Registry loader methods such as:
+	 *        'EE_Request_Handler' => 'load_core'
+	 *        'EE_Messages_Queue'  => 'load_lib'
+	 *        'EEH_Debug_Tools'    => 'load_helper'
+	 * or, if greater control is required, by providing a custom closure. For example:
+	 *        'Some_Class' => function () {
+	 *            return new Some_Class();
+	 *        },
+	 * This is required for instantiating dependencies
+	 * where an interface has been type hinted in a class constructor. For example:
+	 *        'Required_Interface' => function () {
+	 *            return new A_Class_That_Implements_Required_Interface();
+	 *        },
+	 */
+	protected function _register_core_class_loaders()
+	{
+		//for PHP5.3 compat, we need to register any properties called here in a variable because `$this` cannot
+		//be used in a closure.
+		$request = &$this->_request;
+		$response = &$this->_response;
+		$loader = &$this->loader;
+		$this->_class_loaders = array(
+			//load_core
+			'EE_Capabilities'                      => 'load_core',
+			'EE_Encryption'                        => 'load_core',
+			'EE_Front_Controller'                  => 'load_core',
+			'EE_Module_Request_Router'             => 'load_core',
+			'EE_Registry'                          => 'load_core',
+			'EE_Request'                           => function () use (&$request) {
+				return $request;
+			},
+			'EE_Response'                          => function () use (&$response) {
+				return $response;
+			},
+			'EE_Request_Handler'                   => 'load_core',
+			'EE_Session'                           => 'load_core',
+			'EE_System'                            => 'load_core',
+			//load_lib
+			'EE_Message_Resource_Manager'          => 'load_lib',
+			'EE_Message_Type_Collection'           => 'load_lib',
+			'EE_Message_Type_Collection_Loader'    => 'load_lib',
+			'EE_Messenger_Collection'              => 'load_lib',
+			'EE_Messenger_Collection_Loader'       => 'load_lib',
+			'EE_Messages_Processor'                => 'load_lib',
+			'EE_Message_Repository'                => 'load_lib',
+			'EE_Messages_Queue'                    => 'load_lib',
+			'EE_Messages_Data_Handler_Collection'  => 'load_lib',
+			'EE_Message_Template_Group_Collection' => 'load_lib',
+			'EE_Messages_Generator'                => function () {
+				return EE_Registry::instance()->load_lib('Messages_Generator', array(), false, false);
+			},
+			'EE_Messages_Template_Defaults'        => function ($arguments = array()) {
+				return EE_Registry::instance()->load_lib('Messages_Template_Defaults', $arguments, false, false);
+			},
+			//load_model
+			'EEM_Message_Template_Group'           => 'load_model',
+			'EEM_Message_Template'                 => 'load_model',
+			//load_helper
+			'EEH_Parse_Shortcodes'                 => function () {
+				if (EE_Registry::instance()->load_helper('Parse_Shortcodes')) {
+					return new EEH_Parse_Shortcodes();
+				}
+				return null;
+			},
+			'EventEspresso\core\services\loaders\Loader' => function () use (&$loader) {
+				return $loader;
+			},
+		);
+	}
+
+
+
+	/**
+	 * can be used for supplying alternate names for classes,
+	 * or for connecting interface names to instantiable classes
+	 */
+	protected function _register_core_aliases()
+	{
+		$this->_aliases = array(
+			'CommandBusInterface'                                                 => 'EventEspresso\core\services\commands\CommandBusInterface',
+			'EventEspresso\core\services\commands\CommandBusInterface'            => 'EventEspresso\core\services\commands\CommandBus',
+			'CommandHandlerManagerInterface'                                      => 'EventEspresso\core\services\commands\CommandHandlerManagerInterface',
+			'EventEspresso\core\services\commands\CommandHandlerManagerInterface' => 'EventEspresso\core\services\commands\CommandHandlerManager',
+			'CapChecker'                                                          => 'EventEspresso\core\services\commands\middleware\CapChecker',
+			'AddActionHook'                                                       => 'EventEspresso\core\services\commands\middleware\AddActionHook',
+			'CapabilitiesChecker'                                                 => 'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker',
+			'CapabilitiesCheckerInterface'                                        => 'EventEspresso\core\domain\services\capabilities\CapabilitiesCheckerInterface',
+			'EventEspresso\core\domain\services\capabilities\CapabilitiesCheckerInterface' => 'EventEspresso\core\domain\services\capabilities\CapabilitiesChecker',
+			'CreateRegistrationService'                                           => 'EventEspresso\core\domain\services\registration\CreateRegistrationService',
+			'CreateRegCodeCommandHandler'                                         => 'EventEspresso\core\services\commands\registration\CreateRegCodeCommand',
+			'CreateRegUrlLinkCommandHandler'                                      => 'EventEspresso\core\services\commands\registration\CreateRegUrlLinkCommand',
+			'CreateRegistrationCommandHandler'                                    => 'EventEspresso\core\services\commands\registration\CreateRegistrationCommand',
+			'CopyRegistrationDetailsCommandHandler'                               => 'EventEspresso\core\services\commands\registration\CopyRegistrationDetailsCommand',
+			'CopyRegistrationPaymentsCommandHandler'                              => 'EventEspresso\core\services\commands\registration\CopyRegistrationPaymentsCommand',
+			'CancelRegistrationAndTicketLineItemCommandHandler'                   => 'EventEspresso\core\services\commands\registration\CancelRegistrationAndTicketLineItemCommandHandler',
+			'UpdateRegistrationAndTransactionAfterChangeCommandHandler'           => 'EventEspresso\core\services\commands\registration\UpdateRegistrationAndTransactionAfterChangeCommandHandler',
+			'CreateTicketLineItemCommandHandler'                                  => 'EventEspresso\core\services\commands\ticket\CreateTicketLineItemCommand',
+			'TableManager'                                                        => 'EventEspresso\core\services\database\TableManager',
+			'TableAnalysis'                                                       => 'EventEspresso\core\services\database\TableAnalysis',
+			'LoaderInterface'                                                     => 'EventEspresso\core\services\loaders\LoaderInterface',
+			'EventEspresso\core\services\loaders\LoaderInterface'                 => 'EventEspresso\core\services\loaders\Loader',
+			'CommandFactoryInterface'                                             => 'EventEspresso\core\services\commands\CommandFactoryInterface',
+			'EventEspresso\core\services\commands\CommandFactoryInterface'        => 'EventEspresso\core\services\commands\CommandFactory',
+		);
+	}
+
+
+
+	/**
+	 * This is used to reset the internal map and class_loaders to their original default state at the beginning of the
+	 * request Primarily used by unit tests.
+	 */
+	public function reset()
+	{
+		$this->_register_core_class_loaders();
+		$this->_register_core_dependencies();
+	}
 
 
 }