Developing a DSL Abstract Syntax - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 47

helper.setOperationContext(MindmapPackage.Literals.TOPIC,
eOperation);
EAnnotation ocl = eOperation.getEAnnotation(OCL_ANNOTATION_SOURCE);
String body = ocl.getDetails().get("body");

try {
allSubtopicsBodyOCL = helper.createQuery(body);
} catch (ParserException e) {
throw new UnsupportedOperationException(e.getLocalizedMessage());

}

}

Query<EClassifier, ?, ?> query =
OCL_ENV.createQuery(allSubtopicsBodyOCL);

@SuppressWarnings("unchecked")
Collection<Topic> result = (Collection<Topic>) query.evaluate( this );

return new BasicEList.UnmodifiableEList<Topic>(result.size(),
result.toArray());

}

Again, here we see the boilerplate OCL code that configures an
OCLExpression if it's the first invocation, and then it invokes the expression
obtained from the annotation. We leave the mindmap model at this point and
move on to develop the second domain model in our product line.

3.4 Developing the Requirements Domain Model

In a similar fashion to our mindmap model, we create a new org.eclipse.
dsl.requirements DSL project here to hold our requirements model. This
forms the base of our fictitious Requirements Management Project (RMP). We
create the new requirements.ecore model using the Domain Model Wizard
and GMF Ecore diagram, and we complete it to match the diagram and descrip-
tion of Figure 3-7.
Basically, a model contains a collection of RequirementGroups , which con-
tain a number of children groups and Requirements . Requirements have
child references and contain Version and optional Comment elements. A number
of enumerations for Priority , State , Type , and Resolution are also in the
model. A Requirement can also have a number of dependent requirements,
which become the basis for our dependency diagram. Note that the author attrib-
utes are simple strings. We could create a Team model and reference these ele-
ments to assign to our requirements and comments. We also could have a
separate Discussion model to use here and in our mindmap, as a topic might have
an associated discussion thread. Many possibilities exist, but for the purposes of
our sample application, we keep it simple.