Issue #07 Predefined events

[Subbu Allamaraju <subbu@bea.com>]

Several months ago, I raised the question of predefined events. Here is 
a use case and a proposal, for your review and comments.

Regards,

Subbu

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Use Case:

This is a UI-centric use case.

There is an email app consisting of three portlets (a) Folder View, (b) 
List View, and (c) Message View. Folder View displays folders, List View 
displays list of messages in a given folder, and Message View displays a 
message.

The UI requirement is that when the Message View portlet is set to 
"full" window state, the List View should be minimized, and vice versa.

Solution:

a. (Optional) Message View portlet indicates that it can raise a 
WindowStateChanged with name "myurn:full.

b. List View portlet indicates that it would like to receive 
WindowStateChanged event with name "myurn:full".

c. User changes the window state of Message View portlet to full.

d. The Consumer creates and dispatches a WindowStateChanged event 
"myurn:full".

e. The List View portlet then changes its state to wsrp:minimized.

(The event should possibly include some info of the source portlet, but 
that comes under Issue #15 - but in the absence of the source info, 
these portlets can choose to name their events to include some source info).

Proposal:

My proposal consists of two parts:

a. Update the semantics to allow Consumers to create and dispatch 
arbitrary events (not limited to predefined events below).

b. Specify some predefined events

I can think of the following predefined events:

a. WindowStateChanged: Raised when the window state of a portlet changes.

b. ModeChanged: Raised when the mode of a portlet changes

c. Refreshed: Raised when a portlet is refreshed

d. Visible: Raised when a portlet became visible (i.e., included in the
same aggregated page)

e. Invisible: Raised when a portlet became invisible (i.e., not included 
in the same aggregated page)

As we make progress, we can take the question of concrete scehema types, 
event names and types (and their payloads, if any).