+1 on Simon's proposal.
Thanks,
Raymond
From: Simon Laws
Sent: Monday, October 06, 2008 5:58 AM
To: [email protected] ; [EMAIL PROTECTED]
Subject: Re: Request Response Binding - was: Re: Tuscany data binding
framework enhancements
On Fri, Oct 3, 2008 at 8:35 AM, ant elder <[EMAIL PROTECTED]> wrote:
On Thu, Oct 2, 2008 at 1:45 PM, Simon Laws <[EMAIL PROTECTED]>
wrote:
<snip>
I'm particularly interested in those who put the provider framwork in place
see the addition of binding configuration see this as an extension of the
binding providers or see this as a new set of providers?
This is looking like a new type of extension to me, people should be able to
contribute new wireFormatters and have them made available for use within
the Tuscany runtime. Its also looking like this should be possible to do at
the application level.
So Tuscany would come with a bunch of wireFormat extensions just like it
already has a bunch of binding and implementation extensions. Something
somewhere would define what the default wireFormat extension is to use with
each binding when no <wireFormat> element is in the SCDL. So there would be
a self contained JMS wireformat extension which implements the defaults as
defined in section 5.2 in the JMS binding spec and you'd be able to do:
<reference ...>
<binding.jms>
<wireFormat.jms/>
</binding.jms>
</reference>
but that would be the default so the same as:
<reference ...>
<binding.jms />
</reference>
Users could also do
<reference ...>
<binding.jms>
<wireFormat.myFunkyFormatter/>
</binding.jms>
</reference>
and have the 'myFunkyFormatter' extension as part of their application not
some jar that needs to be added to the Tuscany runtime.
We could use the definitions.xml file to define things like the default
formatter for a binding, it also seems like that old discussion on using the
definitions.xml file to declare the extensions would help with the
myFunkyFormatter case as described at:
http://apache.markmail.org/message/unubgkqdcwwch66m
...ant
So there are two points here then
1. wireFormat as a separate extension point.
Ok so that could work. We would need the usual provider structure for
wireFormat and operationSelection. Then we need some new bits to get the
associated interceptors in the right place.
- A wire structure managed by the bindingListener/bindingInvoker
- some predefined "wire format" and "operation selection" phases on the new
wire that ensure that the interceptors get put in the correct place
- A mechanism where, as you suggest, the binding can instigate defaults when
no specifics are included in the SCDL. This could be as easy as completing
the model based on definitions.xml entries
- Code to read the model, select the appropriate factory and popoulate the
new wire with interceptors from the binding and from wireFormat and
operationSelector
2. extension points (wireFormat in this case) provided in SCA contributions
Personally I'd like to keep this separate from 2 for the time being. Only
because it's easier in the first instance to go with adding extensions via
the META-INF/services mechanisms while we work out what the extension points
should look like. Having looked back over the ML conversation on
definitions.xml though it does seem that there was a desire to allow some
extensions to be added to the runtime as part of a contribution. We can't
even do this with policy today so something like wireFormat would be a
isolated case to look at. I still want to get the extension point right
first though. Doesn't stop others looking at this if they want to of course.
Simon
