Btw, I've almost fixed the LinkageError problem :-) I'll commit it after fixing another problem tonight. Next we should short-circuit the context file saving/loading/etc.
Ara. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:xdoclet-devel- > [EMAIL PROTECTED]] On Behalf Of Aslak Hellesøy > Sent: Friday, April 12, 2002 1:11 AM > To: [EMAIL PROTECTED] > Subject: [Xdoclet-devel] Dynamic optional modules > > Hi all, > > As you might know, I've been experimenting with dynamic loading of > optional > modules lately, and I've come up with a solution that seems to work ok. > I'd > like to know what I'll explain how it works. > > There is a new xdoclet.loader package which contains all the logic for > handling dynamic loading. Some of the classes in this package > (ModuleFinder/XDocletXmlParser) introspect jar files located in the same > directory as xdoclet.jar and look for a META-INF/xdoclet.xml "deployment > descriptor" in each of the jars it finds. If an xdoclet.xml file is found, > XDocletXmlParser looks for the following information: > > -what subtasks the module contains, and what parent task they belong to. > -what tag handler the module contains, and the namespace they map to. > > Everything is orchestrated by the Bootstrapper class (which is a task and > will replace <taskdef> for xdoclet tasks), and as the jars are > introspected > it registers the classes (XDoclet core tasks like EjbDocletTask and > WebDocletTask) with the BootstrapClassLoader. This class loader is used as > a > parent for an AntClassLoader, which will be used to load XDoclet classes. > Whenever BootstrapperClassLoader is asked to loadClass a class, it will > check if the requested class is one of the parent tasks that should be > instrumented to add createBlaBla methods. > > The BootstrapperClassLoader uses BCEL (Jakarta's fantastic Byte Code > Engineering Library) to instrument the parent task classes during loading. > All it does is to dynamically insert createBlaBla methods so that Ant will > accept <blabla> sub elements to parent tasks (like <ejbdoclet>). > > So far so good for optional subtasks. The other part is to register tag > handlers contained within the optional modules. Since XDoclet can be > invoked > in a different VM, the tag handlers must be registered in the DocletMain > class. The registered subtasks "survive" the intra-vm transfer because the > subtasks are serialised in DocletContext. In XDocletMain's start method > the > ModuleFinder.findModules() is called again, and this will register the tag > handlers. The actual registration is done inside XDocletModule, which > receives callbacks from XDocletXmlParser. XDoclet and Ant are now ready > fit > for fight. > > All the resources (dtds, templates and Message.properties) are located in > a > resources folder beneath the classes. I suggest we put tag handlers and > subtasks in the same package (as done with WebLogic stuff). The best > argument I can think of for doing it this way is to keep related stuff > close > together on the file system. I don't like to browse too much around for > related stuff. > > I don't know if I have succeeded in describing how it works. It isn't as > complicated as it sounds. Take a peek under xdoclet.loader and the sample > weblogic module implementation, as well as the samples/build.xml arounf > the > <ejbdoclet> task. It should give a fair picture for those of you who > understand code better than prose. > > As ususal, I have been ego. Some of the other developers have made me > aware > that I should share my thoughts and doings more with you guys. Therefore, > consider it all a fictual idea. Just let me know what you think. > > Peace, > Aslak > > > _______________________________________________ > Xdoclet-devel mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/xdoclet-devel _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com _______________________________________________ Xdoclet-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/xdoclet-devel
