Extended CORBA Components
In CCM, the OMG IDL has been extended to define a component type with multiple interfaces and properties. Component is a new basic meta-type in CORBA that can be represented in interface repository.
CCM model has two levels of Components viz.
  • Basic, providing support for basic features needed to componentize a CORBA Application.

  • Extended, provides a richer set of features for supporting multiple interfaces in a Component, Event Sources and Sinks, and Configurable attributes for Components.
Extended Component abstract Model

As shown in above Figure Extended Components support a variety of surface features called ports, which are of five different kinds

  • Facets, which are named interfaces provided by a Component exposing a subset of the interfaces supported by a Component to a Client. Facet represents the access point of the component's functional application behavior.

  • Receptacles are named connection points where external Components can connect to. The connected references can be either Facets or callback references or simple object references. The receptacles are used for connecting component instances together to expose a richer behaviour of component through delegation. A component may support a special type receptacle that can be connected multiple times.

  • Event Sources, are connection points, which emit events for a particular type. CCM defines two port namely publishes and emits to produce events.

  • Event Sinks, are connection points, which accept an Event of a particular type.

  • Attributes, are named values which can be accessed and set through accessor and mutator methods. Attributes are useful for performing Component Configuration.

The Event Model supported by Extended CCM Components is a simple Push Model.

The K2 IDL2 (idl2) pre-processor recognizes newly added keywords for ports and generates the corresponding equivalent IDL 2.x code. Also, the K2 CIDL compiler (cidl2cpp) generates the supporting Component Implementation Framework (CIF) code necessary to write an extended component and deploy it within the K2 Component Server.

Component Interconnections
Connecting Components

As shown in above figure the facets and receptacles can connected to together to provide synchronous connections. The emitters and consumers also can be connected together to provide asynchronous connections between two components. The above process of composing components is known as component assembly. The assembly can be achieved using graphical user interface tool that interacts with user to capture assembly information. The tool can be used to deploy the component assembly into a runtime environment, which handles automatic connection of components. In some cases the application client may perform assembly for additional configuration purposes before executing operations on component.

A sample Vending Machine example is available in the evaluation version to demonstrate component inter-connections and configurations.

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