This section describes the new components and changes components
that can be shared across the Web container and the EJB container. That is,
these components can be used both by the application presentation layer and
the application logic layer.
- Common Hierarchical Area
- This component, called the CHA, uses J2EE technology to wrap contexts
as EJBs so that they are accessible by any entity running in the EJB container.
This enables a business process to get the data it needs. Because the CHA
contexts are EJBs, non-toolkit applications can use the CHA to contain general
global session information.
- CHA contexts
- The contexts running in the application server side, which is called CHA
contexts, is different from those running in the Java(TM) client side. Compared with the contexts
running in the Java client side, the CHA contexts have additional wrapping
so that they exist as EJBs. There is no connection between the contexts and
CHA contexts
- Events
- The events running in the application server side have a different structure
than those running in the Java client side. The application server
side events use Java Message Service (JMS) for events propagation.
- CHA Formatter Service
- This service formats data objects into strings and parses strings into
data objects so that data can move into and out of CHA contexts.
- Externalizers
- Externalizers exist in both layers except that the application logic layer
does not contain externalizers for toolkit entities that are purely related
to presentation such as flow processors and views.