Description Frank Mising name 2010-05-26 11:04:29 EDT

Build Identifier: org.eclipse.osgi_3.5.2.R35x_v20100126.jar

Assume having three plugins: p.hibernate, p.hibernateHelper and p.mySQL. p.hibernateHelper "requires" p.hibernate, since it composes the Session and so on. It has an ExtensionPoint "Configuration" which collects e.g. the driver's class name from p.mySQL, which in turn plugs into that ExtensionPoint. Hence p.mySQL "requires" p.hibernateHelper. And finally (often described) p.hibernate allows buddies to "register". p.mySQL does so and registers to p.hibernate.

This leads to a ClassNotFoundException for com.mysql.jdbc.Driver. If you "require" p.hibernate within p.mySQL, the CNFDE disappears and everything works fine.

I've tracked that down to RegisteredPolicy:

	public Class loadClass(String name) {
		if (allDependents == null)
			return null;
		Class result = null;

The class loading process walks thru it's different steps and finally reaches the buddy loading. Correct! But why does it check for "allDependents"? That might be correct for policy "dependent". But if I "regsiter" myself explicitly, why do I need to "require" also? Seems strange. Shouldn't it be "allRegistrants" or something like that?

Even worse, I've "rexeported" p.hibernate within p.hibernateHelper. Since p.mySQL "requires" p.hibernate, which in turn "requires and reexports" p.hibernate, allDependents should not be empty, shouldn't it?

Maybe I've misunderstood the whole concept. But on the other hand, I cannot find an exhausting reference documentation / detailled users guide for the whole stuff.

Regards
Frank

Reproducible: Always