[Xpipe-developers] draft Java implementation of XComponent for comment

[David S. <ds...@st...>]

I've placed a draft Java implementation of XComponent at
http://www.starrconnect.com/xpipe/JavaXComponent.zip

Structurally the model parallels Sean's python model.

For serialization/deserialization the system uses JDOM.  I had considered
using one of the many data binding frameworks, but I don't know of any that
support RNG.  From a maintainability standpoint I'd rather take the pain of
hand coded serialization than maintaining parallel schemata.  Although that
may just be me.

Each class implements a toJDOM method that returns a JDOM element.  The
XComponent object's toXML method uses JDOM's XMLOutputter to generate XML
text.  A future refactoring enhancement will be to derive each object in the
model from some superclass that implements a single toXML so that each can
generate an XML fragment.

Each class also implements a toString for debugging purposes.  Coming will
be equals and hash methods for those classes that need them.

Error handling is not really addressed yet.  I'll take care of this soon.

For discussion, I have also subclassed XComponent with three classes
JavaXComponent, XSLTXComponent, and PythonXComponent.  There is a
XComponentFactory that can be used to create the correct XComponent object.
It is my intent to be able to invoke the XComponent directly through a
process() method.  I have implemented this for the XSLTXComponent, but the
other two will take some work.  To process an XSLT XComponent, all you'd
have to do is:

	XComponentFactory fact = new XComponentFactory ();
	XComponent xc = factory.getXComponent ("xc0.xco");
	xc.process ({in.xml; out.xml});

Of course, if all this works, the system won't be required to extract code
and other resources won't need to be extracted to disk to execute or test
XComponents.  Thoughts?

If others like this approach I'll keep moving on it.  First building a
classloader to load the code for Java XComponents, then moving on to the
Jython case.

David

David Starr
18 Winthrop Terrace
Wayland, MA  01778
(508) 358-2975
da...@st...