Components and Service-Units

A component can be a service engine or a binding component.
A component may support several roles: it can act as a service provider, a service consumer or both.

A service-unit targets a given component.
A service-unit is used to configure the role of its target component.
Not very role of a component may be configured by a service-unit. It depends on the component.
A service-unit supplies resources and configuration to make its target component emulate a service.

Components classes

The component class is in charge of the component life cycle.
The component class has a pool of (internal) message listeners.
The component class has an object in charge of managing the life cycle of service-units (the Service-Unit manager).

The JBI listener is the class in charge of handling and processing messages coming from the bus.
The JBI listener must check the target end-point, the MEP and the operation name.
JBI listeners work in a pool with a waiting queue.

The external listener is the class in charge of handling external messages and external events to the bus.
External listeners may emit exchanges into the bus.
There are as many external listeners than consumes sections for a given component.

The SU manager is the class in charge of service-units life cycle.
The SU manager is created and maintained by the component class.

Developing Petals components

Petals provides a framework that ease the development of Petals components (the CDK).
Concrete developments steps are listed here.