Here the glossary of the principal terms of JUnivers.
| JUnivers Project |
The project is the entry point of JUnivers. It is defined by in several entries in the dictionary like :
- data sources ("Connections"), their entities ("Entity") and attributes of these last ("Attribute")
- components of data or GUI ("Component"), their composition (child "Component"), messages ("Message") and possibly their dependences on data sources ("RequestBinding", "Request") and/or attributes ("AttributeBinding")
- dependences between components ("Link")
A project has an unique name by JVM.
The JUnivers projects are materialized by the presence of a directory bearing the name of the project which has a ".properties" file also bearing the name of the project.
This file contains at least the parameters of instantiation of the dictionary and the implementation of the "ServerFacade". These directories must be placed in a directory "projects" itself placed in the root of the java classpath.
A project can extend another. It can for example define components referring or inheriting in their turn components defined in the parent project. All the definitions of the parent project are accessible and extendable. |
| JUnivers XML Repository |
The module "XML JUnivers Dictionary" makes it possible to compose the dictionary of a project with the help of XML files organized in the directory of the project.
The definitions of the dictionary can be organized various manners. The entirety of the definitions of the project can for example be placed in the starting file "ApplicationDefinition.xml"; but to gain in clearness, it is preferable to extract the definitions from the principal components to place them in other xml files referred starting from the first.
Another interesting approach is to create two projects. The first, containing the definitions of the data sources and the business objects, the second, extending the first, containing the definition of the structures of the screens. The two layers being thus perfectly distinct, can thus be used separately.
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| Components |
A "JUnivers Session" consists of a tree structure of objects of the type "DefaultComponent". A "DefaultComponent" is the materialization of a "Component" defined in the dictionary.
It is simple starting from a "DefaultComponent" to reach the objects which make it up, with those which compose the latter and so on.
A "DefaultComponent" gives information on the requests and attributes of data which were assigned to him in the dictionary, on the manner of validating them and to present them.
The "DefaultComponent" offers a crowd of access methods in reading and writing to the data sources.
The "DefaultComponent" has a state, i.e. it can have of the data records selected or values of edition when a modification is in hand.
According to the links defined in the dictionary, a "DefaultComponent" can depend on another. For example, at the time of the access to data of a server datasource, a filter can be automatically added to the request so that it returns only one subset of data.
The "DefaultComponent" is Serializable. |
| Boolean Filters |
The Boolean Filter is the JUnivers way to express what is called is the SQL world "The Where Clause".
It is an an object tree of Children Boolean Filters and Filter Values. A Filter Value is a Component ID, a compare operation and a Object value.
Boolean Filter are described in details in the following PDF document (look down)
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You access the JUnivers Javadoc by clicking on one of the following links depending on the version you want to browse :
Click here to read the Boolean Filters getting started Guide (PDF)
Contact us if you want to get more JUnivers documentation, see the "open-source" page. |
