Programming Model and Protocols for Reconfigurable Distributed ...

84 CHAPTER 4. IMPLEMENTATION ASPECTS AND DEVELOPMENT CYCLE SUPPORT
4.8 Programming in the Large
We used Apache Maven [184] to organize the structure and manage the
artifacts of the reference Kompics implementation [19]. The complete
framework counts more than a hundred modules.
We organized the various framework constituents into abstraction and
component packages. An abstraction package contains a Kompics port
together with the request and indication events of that port. A component
package contains the implementation of one component together with
some component-specific events – typically subtypes of events defined in
required ports. The source code for an abstraction or component package
is organized as a Maven module and the binary code is packaged into a
Maven artifact, a JAR archive annotated with meta-data about the package’s
version, dependencies, and pointers to web repositories from where (binary)
package dependencies are automatically fetched by Maven.
In general, abstraction packages have no dependencies and component
packages have dependencies on abstraction packages for both their required
and provided ports. This is because a component implementation will use
event types defined in abstraction packages, irrespective of the fact that
an abstraction is required or provided. This approach of explicit binary
dependencies also enables deploy-time composition.
Maven enables true reusability of protocol abstractions and component
implementations. Users can start a project for a new protocol implementation
and just specify what existing abstractions their implementation
depends on. These are automatically fetched and made available in the
new project. For convenience, our Kompics repositories [19] also contain
JavaDoc and source JARs which are also fetched automatically by Maven.
This enables programmers to seamlessly navigate the source code of the
artifacts their projects depend on, thus enhancing developer productivity.