Hi,
Please see my comments inline.
Thanks,
Raymond
----- Original Message -----
From: "Scott Kurz" <[EMAIL PROTECTED]>
To: <tuscany-dev@ws.apache.org>
Sent: Thursday, October 04, 2007 6:13 AM
Subject: concerns w/ Tuscany databinding framework and Java-centric
databindings
I wonder what we think about the Tuscany databinding framework and how it
could be used with Java-centric databindings (as opposed to say, XML-based
databindings).
Say I'm writing a binding which will use Java serialization to
send/receive
data over the binding transport.
Let's define a new databinding such as "java:serialized" to capture this
format.
One approach would be to use the java.lang.Object databinding for my
binding's interface contract.
We should rename the java beans data binding from "java.lang.Object" to
"java:complexType" to avoid confusions.
I've found that if I want to do this, it seems to be a lot easier if I
introduce a few very basic transformers:
Simple2Object, Object2Simple, DataObject2Object,
with each doing no more than returning the input source object passed to
transform().
Do you try to use these transformers to convert the simple types to the
serialized java format?
Otherwise I end up in transformer chains like:
SimpleJavaType2Node, DOMNode2JavaBeanTransformer
which is unnecessary to simply pass along a Java primitive type.
In your case, we can add a transformer from java:simpleType to
java:serialized to support the pass through. For complex types,
java:complexType --> java:serialized will do.
I'm just wondering, though, how Raymond and others who've given the
databinding framework some thought would react to introducing those
transforms into the web of transformers.
Every entry "pollutes" the web a bit, of course.
Some transformers can only be used as either the first or last edge on the
path. I use a very heavy weight to avoid a transformer to be used as
intermediaries. We can even add a flag to a transformer to tell if it can
serve as an intermediary.
An alternative approach is to do everything possible to avoid the Tuscany
databinding framework and to make sure a DataTransformationInterceptor is
not set up on the wire to/from the binding.
I wonder if that is the "preferred" approach Raymond had in mind?? Of
course the downside of this is that I lose the ability for my binding to
handle, say, a DOM Node, which Tuscany has a transform to Object for.
A good balance is needed. The databinding framework is used to help the
"well-known" types of transformation that can be handled as system code. For
a binding, it expresses its expectation of data format and the framework
helps to meet such requirement.
I realize that there's some other context in my situation I'm not
mentioning. Namely, I'm partly doing things the way I am to workaround
JIRAS 1679,1680.
But still, maybe my question is worth addressing on its own.
Thanks,
Scott
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