Comments on: Custom URL protocols and multiple classloaders http://www.cooljeff.co.uk/2009/12/12/custom-url-protocols-and-multiple-classloaders/ my 2 pence to the world Thu, 01 Jul 2010 18:46:21 +0000 http://wordpress.org/?v=2.8.5 hourly 1 By: admin http://www.cooljeff.co.uk/2009/12/12/custom-url-protocols-and-multiple-classloaders/comment-page-1/#comment-128 admin Sun, 13 Dec 2009 13:02:13 +0000 http://www.cooljeff.co.uk/?p=172#comment-128 Stuart, thanks for this, I was not fully aware of how OSGI works around the various issues and Chapter 11 does a good job at explaining it. Stuart, thanks for this, I was not fully aware of how OSGI works around the various issues and Chapter 11 does a good job at explaining it.

]]> By: Stuart McCulloch http://www.cooljeff.co.uk/2009/12/12/custom-url-protocols-and-multiple-classloaders/comment-page-1/#comment-127 Stuart McCulloch Sun, 13 Dec 2009 02:13:07 +0000 http://www.cooljeff.co.uk/?p=172#comment-127 You might want to look at the URL Handlers Service (chapter 11 of the OSGi core specification http://www.osgi.org/download/r4v42/r4.core.pdf) It defines a service-based approach for registering URL handlers in a modular, dynamic application. The basic idea is that you can register an implementation of URLStreamHandlerService with the OSGi service registry - the various service implementations are then discovered by the real (singleton) URLStreamHandler that's registered by the OSGi framework. The framework handler is responsible for sending incoming requests to the right handler service. You can find a concrete example over at http://wiki.ops4j.org/display/paxurl/Pax+URL which also works in a standard Java environment, except without the dynamic part. Of course, there are some wrinkles (mostly when embedding frameworks inside other containers) but most OSGi frameworks can also support this by using reflection to chain to existing handler factories. You might want to look at the URL Handlers Service (chapter 11 of the OSGi core specification http://www.osgi.org/download/r4v42/r4.core.pdf)

It defines a service-based approach for registering URL handlers in a modular, dynamic application. The basic idea is that you can register an implementation of URLStreamHandlerService with the OSGi service registry – the various service implementations are then discovered by the real (singleton) URLStreamHandler that’s registered by the OSGi framework. The framework handler is responsible for sending incoming requests to the right handler service.

You can find a concrete example over at http://wiki.ops4j.org/display/paxurl/Pax+URL which also works in a standard Java environment, except without the dynamic part.

Of course, there are some wrinkles (mostly when embedding frameworks inside other containers) but most OSGi frameworks can also support this by using reflection to chain to existing handler factories.

]]>