Re: [ve-dev] Re: Using JEM to draw cartoon images of widgets (Namrata)

[Rich Kulp <richkulp@xxxxxxxxxx>]

Hi,

You shouldn't be looking at anything
starting with REM. This is an internal implementation of the IProxy interfaces
for remote vm. You should be accessing the proxies through the IProxy interfaces.
 As I recall you have a well-defined set of visuals and you don't
need a java project and extension capability, so you can run using the
IDE implementation of the IProxys. This will be much faster foy you because
the visuals will not require a remote vm to be started and you won't be
forced to be in a java project (remote vm proxies require a java project,
the IDE implementation does not). Look at IDERegistration.createProxyFactory
methods. IDERegistration is not internal. But the rest of the IDE... stuff
is. We haven't gotton around to making it API yet.


REMExpression is an implementation of
the IExpression interface. What we used to do was use straight IMEthodPRoxy
invokes. This is like calling a method. The problem is that each invoke
requires a round-trip to the remote vm. When we built up GUI's this round-tripping
added up and slowed things down. The _expression_ were used to pipe the invokes
to the remote vm. What happens is that we don't wait for us response, we
just keeping pushing commands to the remote vm. Then at the very end we
do an invoke, and this then waits for all of the previous commands to be
invoked and returns results.

It turns out though that expressions
on IDE proxies is actually slower than using the IMethodProxy invokes.
That is because when using IDE proxies, it turns around and calls things
directly. This is very fast and doesn't have the latency problem that the
sockets have that are used with the remote vm. So if you are IDE it doesn't
require expressions for performance.

However, ComponentManager isn't currently
written to work without expressions. I see now that it might be a good
idea to add calls that don't require expressions. That would make it faster
for you using IDE and no expressions.

Now, the way we connect the EMF model
to the live beans is through an EMF adapter. This adapter (called BeanProxyAdapter
(or BeanProxyAdapter2 depending on what driver you have, we just recently
renamed BeanProxyAdapter2 back to BeanProxyAdapter) controls the live bean.
It hears of changes to the EMF and propagates them to the live beans.

You can use something similiar but I
don't think it needs to be as complex because you have a controlled environment.
You don't have to handle a wide and undetermined range of beans. Your adapter
can simply create the visual, connect it to the ComponentManager, listen
for changes, and update the visual. The visual should be accessed through
the IDE proxies because that is what the ComponentManager expects.

We also have something called a ModelChangeController.
We pipe our command stack through this so that only one thread is making
changes at time. Plus it has a very important added function. You can queue
up runnables during the execution of the commands that will then be executed
at the end of the transaction (the command stack execution). This is important
because things like grabbing images is expensive, so you don't want to
do it over and over during the execution of the command because of changes
happening. So the image grabbing is queued up to the end of the transaction
and only occurs once.

Rich

"Namrata" <namrata@xxxxxxxxxxxxxx>
Sent by: ve-dev-bounces@xxxxxxxxxxx

06/24/2005 01:21 AM

Please respond to
Discussions people developing code for the Visual Editor project

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Subject	[ve-dev] Re: Using JEM to draw cartoon images of widgets (Namrata)

Rich,

Thanks for the information.

I debugged VE today, and came across REMExpression data structure in many
places. I guessed that this is the _expression_ for instantiating a bean?

Will I be need to use/initialize/configure the REMExpression data, or is
it
something internal?

My model is an emf defined xml model. I will need a mapping between the
xml
node and the corresponding swing class? I realized the VE uses an EMF model
on top of the code model. Where can I find the relation between the EMF
model and the corresponding visual class?

Thanks
Namrata.

>
> HI Namrata,
>
> It depends. For us if we have a frame with buttons on it, we only
care
> about the image of the frame because that image will include the image
of
> the buttons since they are on the frame. Since we can get the absolute
> location of the buttons relative to the frame from the ComponentManager,
> we know their position and size and we could just use that as our
child
> figure bounds. Our child figure has a transparent image on it (i.e.
no
> image is painted but it has bounds so that it can be clicked on, or
a
> border drawn around it).
>
> If you wanted only the image of the button to put someplace else other
> than to be within the image of the frame, then you would have to retrieve
> the image of the button separately.
>
> Rich

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