XML Descriptions
Overview
J2EE applications are generated from two descriptions, expressed in XML.
The semantics of the application are represented in an application xml
file, which we refer to as an appl.xml file. This file
describes the following:
- different types of users the application supports (e.g., public,
registered, admin, etc.)
- data objects, including their properties (or variables) and their
methods
- interactions between user types and objects (e.g., for each user type,
which methods on which objects may a user of that type execute?)
- relations between data objects (i.e., conventional relational database
notion of relationships)
Only the data objects for the application are required.
The implementation of the application is represented in an implementation
xml file, which we refer to as an impl.xml file. This file
describes the following:
- different containers the application may use (i.e., HTTP, Web, and EJB
containers)
- layers within containers that will be implemented (e.g., model, view,
controller, and dbms within an application that includes only a Web
container, or, in addition, EJB session, domain model, EJB entity, and dbms
layers for an application that also uses an EJB container)
- type of layer, such as stub for the model layer of an early
prototype used to test navigation among views
- parameters, such as those needed to access a dbms
Only the containers and layers for the implementation are required.
Both types of descriptive files may be created using
tools developed by our project.
Example Files
appl.xml files
impl.xml files