Hi,
I'm not entirely happy with some of the semantics and API for our
events, and I'd like to tidy this up before 0.6. In trunk, we have:
* Project evaluation events
- You use a ProjectEvaluationListener which you add to a Project
- Fires beforeEvaluate(project) and afterEvaluate(project) events
- afterEvaluate() is not fired when project evaluation fails
* Task execution events
- You use a TaskExecutionListener which you add to a TaskGraph
- Fires beforeExecute(task) and afterExecute(task, exception) events
- afterExecute() is fired whether the task succeeds or fails.
Some things I don't like about this:
- The task and project 'after' events have different semantics regarding
when they are/are not fired
- Some times you want the 'after' event to be fired regardless of
success or failure, such as when you are doing some custom logging, or
profiling, or building a UI.
- Some times you want the 'after' event to be fired only on success,
such as when you are doing some additional configuration at the end of
project evaluation
- Often you are only interested in the 'after' event
What I'd like to change:
1. Change ProjectEvaluationListener.afterEvaluate() to have the same
semantics as TaskEvaluationListener.afterExecute()
2. Move the use of ProjectEvaluationListener from Project to Build.
3. Use ProjectAction as another notification mechanism for the project
evaluation events. That is, add
Project.beforeEvaluate(ProjectAction)
Project.afterEvaluate(ProjectAction)
The later would only be fired on successful evaluation.
* Task creation event
Currently you use a TaskLifecycleListener which you add to a Project. It
has a single taskAdded() event
One problem with this approach is that often you want to do exactly the
same stuff to both existing tasks and new tasks, and it's a little odd
to be using a listener for applying an action to existing tasks.
So, I'd like to do away with TaskLifecycleListener and replace it with
TaskAction. That is, add
Project.whenTaskAdded(TaskAction)
Then, we can (later) add a method like Project.allTasks(TaskAction)
which can be passed exactly the same action as the listener method.
Thoughts?
Adam
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