philduba.com

What we're used to
- responding to method calls
- responding to clicks
- the richer the UI, the more we have to deal with interactions, often asynchronously - it's a different way to program
- Asynchronous event handling is foreign to most CF developers (me included!)

Event-Driven Architecture
- event: "a significant change in state" - other definitions on wikipedia.org, but they're more formal
- goal: decouple components - registering to events and reacting when broadcasted (i.e., a user logs in)

Event-Driven Lifecycle
- Components are registered as event handlers - expressing interest in specific events
- Events enter the system - from external systems but can also be the result of internal operations
- Events are dispatched to interested handlers - handlers register for a given event and are executed
- nice diagram, should be on the Connect recording

Event-Handling by Configuration
- Explicit declaration of handlers for events - Mach-II, ModelGlue, HTML/JavaScript (event handlers on various tags), Flex (similar to HTML with event handler attributes in MXML tags)

Event-Hnadling by Convention
- Implicit association (ColdBox, Fusebox 5.5)
- handlers are methods on CFCs that are auto-discovered via a naming and location conventions

Event Handling Dynamically
- Association of handlers and events at runtime (AJAX, Flex)
- AJAX - limited one to one
- Flex - can do more than one and even custom events

Back to ColdFusion
- application frameworks get part of the way there
- declare in XML, not code, nor dynamically add listeners
- we can announce new environments dyncamically
- mostly synchronous

Edmund
- Event-Driven model framework focused on event handling with asynchronous execution
- Event handlers: can be declared in XML, registered dynamically, and be synchronous or asynchronous
- Flex style event handling
- Register a listener for an event (edmund.register("eventName", someObj); someObj.handleEvent(event) is called
- Can specify additional arguments
- Announcing an event - edmund.dispatch("eventName"); anEvent = edmund.new().name("anotherEvent"); edmund.dispatchEvent("anotherEvent");
- Can specify data for events - allows for separation of data and only providing the event with needed data
- has a declarative way of defining data/properties
- create custom events - <cfcomponent> extends "edmund.framework.Event" and then e = edmund.new("events.MyEvent")
- does speak some Mach-II and ModelGlue to make transitions easier or place nicer together

Edmund Workflow
- Has workflow components that implement handleEvent() mothod
    - decision, foreach, seq functions (and more on the way0
    - built off of work done for a client (or at least made him think about)
    - Command pattern objects
- ColdSpring workflow XML is crazy, I can see why in the earlier session Chris Scott said "whoah, I didn't know ColdSpring did that". Sean's doing stuff with ColdSpring I've never really seen before.
- allows for complex event handlers declaratively using ColdSpring

Bubbling events
- idea of "parent" events, register relationships when registering
- can programatically determine whether to bubble the event up using bubble() method

Summary
- Event-Driven Programming allows to create flexible, loosely coupled systems
- apply same approach in CF that we see in Flex
- allows for CF programmers to learn event model used in Flex while working in language already known
- project on RIAForge and Google group mailing list

- general note on the way Sean does programming is that he returns the object on "set" type functionality as opposed to void so it makes chaining easier. Allows for more declaritive style of programming and also makes integration with ColdSpring easier

- one thing I have noticed with some of the presentations is how much some of the stars of the community think at a much higher level than us "padiwans". Dan Vega and I were talking about how going to some of these sessions, we feel we're at a higher level than we think, but then I go to something like this presentation from Sean and realize, as a programmer, I have a ton of room to grow as a developer.