1. Persistent State Service 1 CORBA Component  Component model  Container programming model  Component implementation framework  Component packaging and deployment

2. Persistent State Service 2 The Component Model  Component Implementation Definition Language (CIDL)  Superset of PSDL  Code generation  Component type  Ports  Facets: specifies a component’s functionality as a set of interfaces rather than as a single interface with simple IDL interface definition  Configuration ports: specifies how a component can be connected to other components that communicate either through invocation or event notification  Basic component Regular CORBA object  Extended component  Component homes: generalizations of the factory design pattern for creating, locating component instances  Component instances are accessed through regular CORBA object references

3. Persistent State Service 3 Facets  Facets: specifies a component’s functionality as a set of interfaces rather than as a single interface with simple IDL interface definition #include Module ComponentEventChannel { interface ManagedObject { // management operations }; component EventChannelComp supports ManagedObject { // facets provides ProxyPushConsumer proxy_push_consumer; provides ProxyPushSupplier proxy_push_supplier; provides ProxyPullConsumer proxy_pull_consumer; provides ProxyPullSupplier proxy_pull_supplier; }; }

4. Persistent State Service 4 Facets  Component equivalent interface interface EventChannelComp:Components::CCMObject, ManagedObject{ ProxyPUshConsumer proxy_push_consumer(); ProxyPushSupplier proxy_push_supplier(); ProxyPullConsumer proxy_pull_consumer(); ProxyPullSupplier proxy_pull_supplier(); };

5. Persistent State Service 5 Facets Equivalent interface Facets proxy_push_consumer proxy_pull_consumer proxy_push_supplier proxy_pull_supplier

6. Persistent State Service 6 Configuration and Composition Ports  Attributes and inheritance  Attributes are declared in a component definition  Attributes should be used only for configuration purposes  Inheritance between component types is restricted to single inheritance  Receptacles  A named connection point that accepts interfaces and connects these to the component for future use.  Event sources and sinks  Special facets and receptacles

7. Persistent State Service 7 Component Ports Equivalent interface Facets Event sinks Attributes component Receptacles Event sources

8. Persistent State Service 8 Component Homes  Primary entry point for clients into the world of component  Type managers for component types  Provide set of operations  Default operation: no-argument factory operation for components of the type they manage  More factory operations  Find operations to retrieve individual, preexisting component instances

9. Persistent State Service 9 Component Container  Container: runtime environment for component instances  Functionality of the containers:  Create and manage component instances  Provide a simplified standard API to the CORBA services

10. Persistent State Service 10 Component Container Home POA Component Internal CallbacksExternal TransactionsSecurityPersistenceNotification ORB Client

11. Persistent State Service 11 Component Categories  Component categories is defined in CIDL, not in IDL  Not properties of component types  Categories  Service  Lifetime of service component is restricted to the lifetime of a single operation  Cannot be associated with persistent state  Transient state is not visible to clients  Require no client interaction  Home for service components provides only factory operations, not finder operations  Computation that only return results can be thought of as service component

12. Persistent State Service 12 Component Categories  Categories  Session  Has only transient lifetime and no persistent state  Have a lifetime of client interaction  Online shopping  Process  Has persistent reference and persistent state  Model business processes  Well-defined lifetime  Component home provide factory operations, no finder operations  Entity  Modeling persistent entities  Expose their persistent identity, i.e., a primary key  Home provide a finder operation

13. Persistent State Service 13 Component Packaging and Deployment  Deployment  Selecting target containers for component implementations  Installing component homes and instances from packages  Configuring component properties  Connecting components via interface and event ports  Descriptors  Software package descriptors  Component descriptors  Component assembly descriptors  Property file descriptors