The Chaupal
JP2P Architecture

The Chaupal JP2P Architecture aims to provide a generic container structure for JAVA based peer to peer (P2P) applications, and tools to make the development of P2P applications a lot easier. The architecture contains a number of bundles, divided over three (GitHub) projects, that each add a layer of functionality to Java P2P. The bundles that make Chaupal are depicted below


At the bottom we see the JXSE 2.8x library, formerly known as JXTA^TM. The code of this library is divided over a number of bundles that make JXSE-LIB.Although these are OSGI bundles, they have no dependencies with OSGI, so they can be deployed as POJO's., In other words, if you put the bundles in your classpath, you should be able to deploy a JXTA^TM application, as if you were using the regular JAR...
..but with one big difference! If you rermove, say, net.jxse.jetty- you will not end up with runtime exceptions. Instead, you will not be able to use the JXTA^tm HTTP service provided by Jetty. This is a big advantage if you only need TCP endpoint services for your applications. Another example are the two databases - derby and H2- which are shipped with the standard JXTA^TM jar; you can select one or the other for your application, but both jars need to be available on the classpath. The modular approach provided by OSGI allows, you to select the jar (bundle) you need, and skip the other.This way you application can really benefit from light-weight components without any unnecessary clutter!

One bundle uses the others: net.jxse.practical.jxta, which implements the code of the corresponding book. With respect to the original code, the 2.8x version of JXTA^TM makes a functional distinction between:

• net.jxta: core functionality
• net.jxta.platform: configuration code (i.e. NetworkManager and NetworkConfigurator)
• Third party additions (Jetty, Netty, Derby, etc.)

The level of JP2P Core implements the JP2P container. This is also a bundle which can be used as a POJO. The container is not dependent on JXTA^TM either. This is handled by the net.jp2p.jxta bundle. Only at the level of the four bundles that complete the JP2P core package, the specific OSGI dependency is made, all of which provide specific services for the JP2P container:net,chaupal: general services:

• net.jp2p.jxse.compatibility: a bridge that allows existing JXTA^TM code to run on the JP2P container
• net.jp2p.chaupal.jxta: JXTA^TM services
• net.jp2p.chaupal.jxta.platofrm: JXTA^TM platform services.

These four bundles use the OSGI declarative service mechanism to register their services to the JP2P container. If one of these bundles is not available or not started, the corresponding JP2P services are not registered, and cannot be used by the JP2P container.

At the top level, there are three bundles that are specific to Eclipse and Equinox, and these provide tools for the Eclipse RCP, such as templates, perspectives and, in the particular case of net.jp2p.chaupal.equinox, jp2p services that has dependencies with equinox code. This bundle will therefore not work on Apache Felix or Knopflerfish without additional handwork.