Code First - Transports

A NetKernel transport monitors for events and when one is detected it interprets the event, builds a corresponding request and issues that request into the address space of the module hosting the transport.

The module hosting a transport is called a Fulcrum, so named because the module that hosts a transport is usually the pivot point for the set of modules that constitute an application. The Frontend Fulcrum, installed in the directory [install]/modules/mod-fulcrum-frontend/, hosts an HTTP transport that listens on port 8080.

When the HTTP transport detects an event (an incoming HTTP request) it interprets it, constructs a NetKernel request and injects the request into the fulcrum module's address space.

Our tutorial module is one of the modules imported by the frontend fulcrum and since it exports the logical address space starting with ffcpl:/tutorial/ any requests of the form http://localhost:8080/tutorial/... are injected into the fulcrum as ffcpl:/tutorial/... and are routed to the tutorial module.

http://localhost:8080/tutorial/helloworld (at the transport)

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ffcpl:/tutorial/helloworld                (in the fulcrum)

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ffcpl:/tutorial/helloworld                (in the tutorial module)

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ffcpl:/helloworld                         (after the rewrite rule)

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org.ten60.netkernel.tutorial.HelloWorld   (sent to the processRequest method)

Nothing in the NetKernel infrastructure is HTTP specific. It is straightforward to create transports to handle any sort of network application protocol or external system event whether it is a CRON time or a GUI event. In each case the event causes an internal root request to be issued into NetKernel's address space. NetKernel's use of URI addressing and resources internally is so similar to the way the Web works one could say that NetKernel brings the Web inside of software.

Now you have a complete working example of a Hello World! program for NetKernel. In the next sections we will expand on this to introduce more features and benefits of resource oriented computing.