Generic inter-component event mechanism
---------------------------------------
Key: WICKET-1312
URL: https://issues.apache.org/jira/browse/WICKET-1312
Project: Wicket
Issue Type: New Feature
Components: wicket-extensions
Affects Versions: 1.3.0-final
Reporter: Timo Rantalaiho
Attachments: Generic_EventBroadcaster.patch
The attached patch provides a generic mechanism for transmitting
inter-component events within a page. This has grown primarily from the need to
repaint all relevant ajax components after an event, but can be used also in
non-ajax environments such as after normal form submits.
The basic idea is to fire an IVisitor on the page of the component sending an
event, giving as an argument an event-specific listener interface that must be
implemented by the components willing to receive the events. They can then do
whatever they need such as add themselves to the AjaxRequestTarget that can be
supplied in the event.
Sometimes the basic Wicket mechanisms such as sharing a model are not enough;
particularly repainting all relevant components in Ajax events gets tedious if
the components are far away from each other in a complex DOM tree.
The benefits of this approach are
- loose coupling between the sending and receiving end
- however, because of strong static typing it's easy enough to find with an IDE
from where the events are broadcasted and where they are received
- good testability (EventBroadcaster can be mocked on the sending end, and
event handlers tested directly on the receiving end, possibly with mock events)
- no need the keep references to Component instances or their paths (which
could have been problematic on repeaters)
(This is not a real observer or listener pattern implementation because the
components cannot register and unregister themselves dynamically, but
"registering" is handled statically on a class basis by implementing the
relevant event receiver interface.)
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
