Sunday, October 31, 2010

Re: Announcing GWT 2.1

On 31 oct, 13:40, Jeff Schwartz <> wrote:
> Thomas,
> It is the 'I' in DI that I reflected on: Injection takes cpu cycles and on
> App Engine server cpu cycles are severely restricted by numerous quotas; the
> penalty for exceeding them cause cascading conditions of failure. If you
> aren't familiar with App Engine hosting and its quotas perhaps you should
> read up on it.

I never used AppEngine so I apologies for not knowing the quotas and
what impact could DI have.

> As for ROO not generating server side DI as part of its tooling in STS when
> used with GWT I will have to check that out for myself; I believe I had read
> that it generates a server side application context configuration file and
> if that is the case then I'd like to know why it would do that if DI wasn't
> employed on the server. If that is the case then DI would certainly cause
> heightened latency causing an increase in 500 errors on App Engine virtual
> server cold starts.

Not having tried Roo, I can only talk about what's visible in the
Expenses sample:
and what I understand from Roo's addon-gwt source code:

And I don't see DI here (on the server-side)

> As for DI being a best practice (that you'd encourage *anyone* to follow)
> well that is your opinion that is not shared by everyone. I encourage a more
> conservative approach to any engineering problem - use the right set of
> tools at the right time.

Sure. I maintain what I said though: DI is a pattern that makes code
easier to test and to maintain. And I really mean DI, as a pattern,
I'm not talking about any tool here; you're free to implement DI
"yourself", it doesn't necessarily means Guice or Spring or JavaEE 6
or whatever (which means you could do it with very low overhead, if
any). I found DI really improved software quality overall.

That being said, let me paraphrase you: "I am open minder. We
developers have to be :) and as such I would very
much like to be proven wrong on all these counts."

> As for Huh!?! That is something best saved for your friends on Facebook.
> This is a technical news group where such antics of conversation are not
> appreciated regardless of difference of opinion.

Sorry, I'm not a native English speaker/writer, so I probably misuse
idioms sometimes.

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