Dear Developers,
As
part<http://www.google-melange.com/gsoc/proposal/review/google/gsoc2011/dragansah/1>of
GSOC 2011 I'm doing (as well as some other things) a contextmenu mixin
that should work with the t5 grid. The mixin works fine on other components
but the t5 grid is tricky because I want to apply a context for the menu for
each cell (and row) i.e. provide a way to show different content based on
the cell (and row) value.
I have read threads on the list where when someone is trying to extend a t5
component like the grid with something the grid was "not intended to do",
the comment on the list can be make a new component etc. but IMO it would
be awesome if t5 allowed doing things like this.
I have the t5 grid integration with the contextmenu mixin working, but it
involves some changes in GridCell and AbstractPropertyOutput, and a change
that introduces another GridOutputContext service (similar to
PropertyOutputContext) that don't break anything (tests don't fail) but are
only there for components like the contextmenu that want to pull cell data
from the grid rendering cycle, to be used outside in a mixin for the grid
or similar. I want to make a patch for the contextmenu component but IMO you
(the developers) won't be so thrilled in commiting such changes, and I can
say I would agree with you if this was the case.
So please read on while I make a proposal for extending the t5 concept of
mixins just a bit.
In t5 the semantics of the components is generally exposed as @Parameter s,
public methods, render cycles and events. While this component model is
very convenient and powerful it doesn't (out of the box) have a way to
expose the structure of the component to the outside world. OK you can argue
that what's inside the component is a private implementation, and should not
be changed by an outside component for example, but please consider this
example: The t5 grid component has gridRows and gridCells. This simple fact
about grid's structure should not change (IMO) and should be possible to be
exposed outside the grid, for components or mixins (like the contextmenu)
can use it.
Not to be too long I don't have some ground breaking suggestion for some
radical change but I have a simple suggestion, that if I get positive
comments from the devs would like to work on right away.
I suggest that a mixin applied on a component should be able not only to
have the component's render phase events, but also have the render phase
events from embedded components in that component.
Example:
Let's have <t:grid t:mixins="contextmenu" />
ContextMenu.java (mixin)
void afterRender() {
...
}
// not possible now
void afteRenderFromGridCell(){
...
}
I guess one downside would be that users start making mixins that
use embedded components that change (or get removed) in the future, but
maybe we can control this by having something like
@ExposeRenderEvents(GridCell.class, GridRows.class) or something similar.
Does anyone consider this extension worth having?
Cheers,
Dragan Sahpaski
