Thursday, April 09, 2009

SpringSource dm Server 2.0 M1

As in Rob's blog, we recently shipped the first milestone of dm Server v2.0. Apart from some new function, this marks an opening up of the dm Server development process with publicly accessible subversion repositories and issue tracker.

The 2.0 roadmap is pretty exciting, and includes constructing a Reference Implementation for RFC 66 ("web container for OSGi") from the existing web components of dm Server.

I'm spending most of my time down in the dm Kernel implementing "cloning" which, roughly speaking, enables a bundle to be wired more than one way, which is not normally possible in OSGi. Cloning copies bundles into an application's scope. This enables the OSGi resolver to have another go at wiring the dependencies of the cloned bundles in a way which suits the application. More information on cloning is included in the above blog entries.

Application scopes can be thought of as an alternative to "nested" OSGi frameworks, which are being specified in the OSGi Alliance and implemented in Equinox. The contents of an application scope can "see" all the contents of the global scope which are not "shadowed" in the application scope. The contents of a nested framework can, by default, not see any of the content of the parent framework(s) unless the nested framework is explicitly defined to see some of the parents' contents.

Much of what we're learning about cloning into application scopes, such as how to calculate what needs cloning and how to manage cloned extenders, will also apply to cloning into nested frameworks if and when that becomes necessary.

No comments:


OSGi (130) Virgo (59) Eclipse (10) Equinox (9) dm Server (8) Felix (4) WebSphere (3) Aries (2) GlassFish (2) JBoss (1) Newton (1) WebLogic (1)