D•OM has modular, opened and stretchable architecture, allowing it to welcome generators of code or documentation.

Many generators are included in standard, the others can be easily developed to correspond to the specific necessities of a project or to target a language not supported yet.

Transformation principe

A generator implements transformation rules. Each rule describes how to produce one element of the target architecture depending on the given D•OM object model elements. The model can be enhanced with annotations which will be used as generation parameters.

These generators favor the capitalization of a reusable technical know-how in the other projects.

The automation of treatments guarantees a bigger reliability of the target code.

Extension of D•OM : the DomExtender component

A generator appears as an extension of D•OM, that is as a sort of module which comes to enrich the modelling environment. An extension of D•OM is developed using D•OM, with the same environment as for the functional prototyping.

So it is not necessary to learn a new language to develop an extension and all the power of the object modelling is available in order to specify the transformation rules. The user interface is automatically generated and integrated in D•OM interface.

D•OM integrates some predefined componants which allow :

• Model access : the object model is available as an instances network issued from the UML metamodel. Searching and updating operations are publicated by the metamodel. (DomTool component).
• Annotations : an extension can associate with any model entity a set of informations as name-value couples (UML defines such couple as "Tagged value"). The extension can also define a GUI to control the annotations inputs. An extension can consult the annotations defined by other extensions. DomExtender provides editor skeletons to facilitate the development of specific editors for every tool. You can see below the annotation editor of the Persistence tool.

• File generation with preserved sections : So the generated code can be "manually" completed, this code is directly introduced in the generated file inside portions reserved for this usage, it will be protected during following generations. Below, in the example of code generation from JavaTool, sections to be protected are framed with lines of comments including "preserved = true".

// (Begin Article:new:Header preserved = false

public Article _new( String name, Object price) throws DomFailure {

// )End Article:new:Header

// (Begin Article:new:Body preserved = false

this.setName(name);

this.setPrice(price);

// )End Article:new:Body

// (Begin Article:new:User preserved = true

// This section will be preserved at the next code generation.

// )End Article:new:User

// (Begin Article:new:Footer preserved = false

return this;

}

// )End Article:new:Footer

• HTML or RTF (Rich Text Format) file generation : a set of primitives are given in order to simply generate the documentation.

Code generators

Only the Java generation and persistence tools are delivered as example with D•OM. A complete and automated chain of development allowing the implementation of a business object server in distributed architecture Java / CORBA is proposed in a separate offer. Please consult us to know the availability of generators adapted to your needs.

Both generators delivered normally are describe in the following paragraphs:

• The generator of objects in Java (JavaTool component),
• The generator of SQL schemes (Persistence component).

Generation of objects in Java, JavaTool component

Application software objects are intended to run on the 3 tiers application server. They are generated from the business model. The implemented transformation principle produces classes Java having a behavior identical to that of the prototype generated by D•OM. However, some limitations were imposed to guarantee that the obtained Java source code is human-readable, maintainable and equivalent to the code written manually.

The correspondence between an UML class diagram UML (D•OM) and Java is rather simple because the concepts are close. The rules of transformation respect the usual standards of coding in Java, in particular those defined by Sun under the name JavaBean.

Generation of persistence, Persistence component

From an object model, defined in a set of packages, the D•OM extension named Persistence generates automatically the relational scheme necessary for the memorization in database of the model instances. Model annotations allow to steer the generation: for example, to specify the classes for which the instances should be memorized in the database, or to specify the names which will be used in the database (name of table, columns, etc.).
The result of the generation is a set of SQL scripts, whose purpose is to create the scheme (table, keys, constraints, stored procedures), to destroy the scheme, to activate or to deactivate the constraints.
The target database is Oracle, version 7 and later.

 

(c) Atos 2000, last page modification: january, 4th 2001