jplugin
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JPlugin is a framework for managing, controlling, and accessing Java-based pluggable components. Components are typically jars that may include other jars and/or resources. The default messaging scheme is synchronous and exchanges POJOs between the main application and the plugins. Plugins are loaded within their own isolated classloader and uniquely identified by a name/version combination which allows concurrent loading of multiple versions of the same plugin.

Primary components like the PluginManager, message Router, message Envelope, and EventManager are interfaces which allows custom implentation if the default implementations aren't sufficient for your project requirements. The current implementation uses a synchronous messaging scheme to talk to plugins. Future versions may also add asynchronous messaging and dynamic proxies (for tighter coupling of the main application to its plugins).

Phase I Requirements

• Small footprint, minimal dependencies
• Interface-based components to allow for custom implementations of plugin management and messaging
• Isolated classloaders per plugin
• Embedded jars and resources in plugin
• Loosely-coupled message routing workflow
• Plugin deployed as jar or directory
• Re-use MANIFEST.MF syntax
• JMX control and monitoring
• Dynamic loading and unloading
• Static loading and unloading

Phase I Pseudo-Requirements

Pseudo-requirements are those that aren't dictated by the project, but are interesting ideas or technologies we wanted to implement.

• Tightly-coupled, dynamic proxy access to plugin classes
• Java 5 generics and annotations
• Small XML descriptors
• Xstream
• TestNG unit testing

Project highlights

Initial Functionality Completed

JPlugin is functional and currently meets all the initial requirements. The initial Router implementation (SimpleRouter) currently supports either direct addressing to a specific version of a plugin or the most current revision of a plugin.

JPlugin presented at Java In Action 2005

JPlugin was introduced at Java In Action as a possible solution to a very small-scale JBI-like implementation for factory floor system integration. The presentation slides can be viewed at this link.

Releases

coming soon...

Examples

coming soon...