From bd94fdd4ec52010dd5426487fc1d5b3ddadedbf8 Mon Sep 17 00:00:00 2001 From: Fabio Bas Date: Mon, 25 Nov 2013 19:27:11 +0100 Subject: Quickstart: added event priority/behaviours/global events doc --- .../protected/pages/Fundamentals/Components.page | 211 ++++++++++++++++++++- 1 file changed, 210 insertions(+), 1 deletion(-) (limited to 'demos/quickstart/protected/pages/Fundamentals/Components.page') diff --git a/demos/quickstart/protected/pages/Fundamentals/Components.page b/demos/quickstart/protected/pages/Fundamentals/Components.page index 9326d89c..84c6070c 100755 --- a/demos/quickstart/protected/pages/Fundamentals/Components.page +++ b/demos/quickstart/protected/pages/Fundamentals/Components.page @@ -96,7 +96,216 @@ $button->OnClick->add( $callback ); $button->OnClick[] = $callback; $button->attachEventHandler( 'OnClick' , $callback ); -where $callback refers to a valid PHP callback (e.g. a function name, a class method array($object,'method'), etc.) +

+ The variable $callback contains the definition of the event handler that can be either a string referring to a global function name, or an array whose first element refers to an object and second element a method name/path that is reachable by the object, e.g. +

+ + +

Global events

+

+With the addition of behaviors, a more expansive event model is needed. There +are two new event types (global and dynamic events) as well as a more comprehensive +behavior model that includes class wide behaviors. +

+

+A global event is defined by all events whose name starts with 'fx'. +The event name is potentially a method name and is thus case-insensitive. All 'fx' events +are valid as the whole 'fx' event/method space is global in nature. Any object may patch into +any global event by defining that event as a method. Global events have priorities +just like 'on' events; so as to be able to order the event execution. Due to the +nature of all events which start with 'fx' being valid, in effect, every object +has every 'fx' global event. It is simply an issue of tapping into the desired +global event. +

+

+A global event that starts with 'fx' can be called even if the object does not +implement the method of the global event. A call to a non-existing 'fx' method +will, at minimal, function and return null. If a method argument list has a first +parameter, it will be returned instead of null. This allows filtering and chaining. +'fx' methods do not automatically install and uninstall. To install and uninstall an +object's global event listeners, call the object's listen and +unlisten methods, respectively. An object may auto-install its global event +during __construct by overriding getAutoGlobalListen and returning true. +

+

+As of PHP version 5.3, nulled objects without code references will still continue to persist +in the global event queue because __destruct is not automatically called. In the common +__destruct method, if an object is listening to global events, then unlisten is called. +unlisten is required to be manually called before an object is +left without references if it is currently listening to any global events. This includes +class wide behaviors. +

+

+An object that contains a method that starts with 'fx' will have those functions +automatically receive those events of the same name after listen is called on the object. +

+

+An object may listen to a global event without defining an 'fx' method of the same name by +adding an object method to the global event list. For example +

+ +$component->fxGlobalCheck=$callback; // or $component->OnClick->add($callback); +$component->attachEventHandler('fxGlobalCheck',array($object, 'someMethod')); + +

Events between Objects and their behaviors, Dynamic Events

+

+An intra-object/behavior event is defined by methods that start with 'dy'. Just as with +'fx' global events, every object has every dynamic event. Any call to a method that +starts with 'dy' will be handled, regardless of whether it is implemented. These +events are for communicating with attached behaviors. +

+

+Dynamic events can be used in a variety of ways. They can be used to tell behaviors +when a non-behavior method is called. Dynamic events could be used as data filters. +They could also be used to specify when a piece of code is to be run, eg. should the +loop process be performed on a particular piece of data. In this way, some control +is handed to the behaviors over the process and/or data. +

+

+If there are no handlers for an 'fx' or 'dy' event, it will return the first +parameter of the argument list. If there are no arguments, these events +will return null. If there are handlers an 'fx' method will be called directly +within the object. Global 'fx' events are triggered by calling raiseEvent. +For dynamic events where there are behaviors that respond to the dynamic events, a +TCallChain is developed. A call chain allows the behavior dynamic event +implementations to call further implementing behaviors within a chain. +

+

+If an object implements IDynamicMethods, all global and object dynamic +events will be sent to __dycall. In the case of global events, all +global events will trigger this method. In the case of behaviors, all undefined +dynamic events which are called will be passed through to this method. +

+

+

Behaviors

+

+There are two types of behaviors. There are individual object behaviors and +there are class wide behaviors. Class behaviors depend upon object behaviors. +

+

+When a new class implements IBehavior or IClassBehavior or +extends TBehavior or TClassBehavior, it may be added to an +object by calling the object's attachBehavior. The behaviors associated +name can then be used to enableBehavior or disableBehavior +the specific behavior. +

+

+All behaviors may be turned on and off via enableBehaviors and +disableBehaviors, respectively. To check if behaviors are on or off +a call to getBehaviorsEnabled will provide the variable. +

+

+Attaching and detaching whole sets of behaviors is done using +attachBehaviors and detachBehaviors. clearBehaviors +removes all of an object's behaviors. +

+

+asa returns a behavior of a specific name. isa is the +behavior inclusive function that acts as the PHP operator instanceof. +A behavior could provide the functionality of a specific class thus causing +the host object to act similarly to a completely different class. A behavior +would then implement IInstanceCheck to provide the identity of the +different class. +

+

+Class behaviors are similar to object behaviors except that the class behavior +is the implementation for all instances of the class. A class behavior +will have the object upon which is being called be prepended to the parameter +list. This way the object is known across the class behavior implementation. +

+

+Class behaviors are attached using attachClassBehavior and detached +using detachClassBehavior. Class behaviors are important in that +they will be applied to all new instances of a particular class. In this way +class behaviors become default behaviors to a new instances of a class in +__construct. Detaching a class behavior will remove the behavior +from the default set of behaviors created for an object when the object +is instanced. +

+

+Class behaviors are also added to all existing instances via the global 'fx' +event mechanism. When a new class behavior is added, the event +fxAttachClassBehavior is raised and all existing instances that are +listening to this global event (primarily after listen is called) +will have this new behavior attached. A similar process is used when +detaching class behaviors. Any objects listening to the global 'fx' event +fxDetachClassBehavior will have a class behavior removed. +

+

Dynamic Intra-Object Events

+

+Dynamic events start with 'dy'. This mechanism is used to allow objects +to communicate with their behaviors directly. The entire 'dy' event space +is valid. All attached, enabled behaviors that implement a dynamic event +are called when the host object calls the dynamic event. If there is no +implementation or behaviors, this returns null when no parameters are +supplied and will return the first parameter when there is at least one +parameter in the dynamic event. +

+ + null == $this->dyBehaviorEvent(); + 5 == $this->dyBehaviorEvent(5); //when no behaviors implement this dynamic event + +

+Dynamic events can be chained together within behaviors to allow for data +filtering. Dynamic events are implemented within behaviors by defining the +event as a method. +

+ +class TObjectBehavior extends TBehavior { + public function dyBehaviorEvent($param1, $callchain) { + //Do something, eg: $param1 += 13; + return $callchain->dyBehaviorEvent($param1); + } +} + +

+This implementation of a behavior and dynamic event will flow through to the +next behavior implementing the dynamic event. The first parameter is always +return when it is supplied. Otherwise a dynamic event returns null. +

+

+In the case of a class behavior, the object is also prepended to the dynamic +event. +

+ +class TObjectClassBehavior extends TClassBehavior { + public function dyBehaviorEvent($hostobject, $param1, $callchain) { + //Do something, eg: $param1 += $hostobject->getNumber(); + return $callchain->dyBehaviorEvent($param1); + } +} + +

+

+When calling a dynamic event, only the parameters are passed. The host object +and the call chain are built into the framework. +

+ +

Global Event and Dynamic event catching

+ +

+Given that all global 'fx' events and dynamic 'dy' events are valid and +operational, there is a mechanism for catching events called that are not +implemented (similar to the built-in PHP method __call). When +a dynamic or global event is called but a behavior does not implement it, +yet desires to know when an undefined dynamic event is run, the behavior +implements the interface IDynamicMethods and method __dycall. +

+

+In the case of dynamic events, __dycall is supplied with the method +name and its parameters. When a global event is raised, via raiseEvent, +the method is the event name and the parameters are supplied. +

+

+When implemented, this catch-all mechanism is called for event global event event +when implemented outside of a behavior. Within a behavior, it will also be called +when the object to which the behavior is attached calls any unimplemented dynamic +event. This is the fall-back mechanism for informing a class and/or behavior +of when an global and/or undefined dynamic event is executed.

Namespaces

-- cgit v1.2.3