The component execution model is the piece in charge of:
Synchronize status between components and their client representation.
Execute the appropriate code in response to events, by delegating on the event management system.
Let's see it in a diagram:
Most important pieces within this diagram are:
Event handler: The event handler is notified about events as soon as they are fired from the user interface. Lion brings a default implementation, really useful since it has a naming convention to define methods associated to events and components: The __EventHandler class.
End-points: End points are classes representing properties, callbacks and whatever we need to bind between components and their interface representations.
In that sense, there are 2 kind of end-points:
Client end-points, representing what we need to bind from the client-side (i.e. a text property within an HTML input element)
Server end-points, representin what we bind to components (i.e. a text property within a server-side component representing a text area).
A pair compound by a client and a server end-points is what we associate in what we know as UI Binding, a rule about how client and server are synchronized to.
Component Pool: A collection where all the components within our application are living in. Components implementing the __IPoolable are stored automatically in the component pool during the user session until they are deleted.
Component Handler: Contain a reference to all the components associated to a concrete view.
Event handler
Everytime an event is fired in the client-side (i.e. a click on a button or just by changing the selection in a combobox) a piece within the server side will catch the event and execute a concrete code (if defined) as a consequence of it.
The event handler is the piece in charge of perform this task. To read more about event handling in Lion, take a look at Event Handlers.
