arch@glassfish.java.net

Re: [arch] Re: Some follow-up proposals and questions after the app client container review

From: Bill Shannon <bill.shannon_at_sun.com>
Date: Thu, 12 Feb 2009 16:27:20 -0800

I think Roberto and I disagree on this.

I like the builder pattern with static factory methods that return a
builder object, from which you get an object representing the running
app client container.

I think having different builder (config) classes for the different
cases is overkill. If some methods really need to be prohibited in
certain cases, I think IllegalStateException is fine.

I definitely don't like having "startContainer" be a static method that
operates on a config, rather than being a method *of* the config (builder).

Also, while our current implementation may limit your ability to start
a container more than once, I can imagine that we might want to remove
that limitation in the future, and I wouldn't want to have to redesign
these classes at that point. (I don't think your proposal has that
limitation, but I think Roberto's proposal did.)


Tim Quinn wrote:
> I have posted a part of the JavaDoc for the updated embedded ACC API here:
>
>
> http://wiki.glassfish.java.net/attach/Gfv3AppclientcontainerOnepager/AppClientContainer.html
>
>
> The links from that page to other classes do not work, but this class
> (and its JavaDoc page) contain all the top-level entry points and also
> includes a discussion of how to use the API.
>
> To summarize briely:
>
> I have been able to avoid the entire state management issue by crafting
> an API in which the calling program:
>
> 1. Uses a static factory method AppClientContainer.newConfig to get the
> appropriate type of Config object (SingleClassConfig vs. ArchiveConfig).
>
> 2. Invokes methods on the Config object to refine the settings in the
> config. Method invocation chaining as Roberto described works.
>
> 3. Invokes the static AppClientContainer.startContainer(Config config)
> which returns an AppClientContainer instance.
>
> 4. The AppClientContainer exposes a stop method.
>
> In spirit this approach accomplishes what I think Roberto was striving
> towards - using the compiler to enforce correct usage rather than
> throwing exceptions at runtime upon detecting improper usage. In
> practice this approach achieves this goal without having to resort to
> separate classes to represent separate states of the container.
>
> I am in the process of greatly revising the one-pager itself, so do not
> expect to see this discussed there yet.
>
> - Tim