Graphical Modeling Framework Runtime - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 369

Figure 10-20 Diagram rulers and grid preferences

10.2 Notation Model

Used by the runtime to manage diagram element, position, and style attributes,
the notation model also allows for persistence of diagrams to the file system. The
notation model provides the link between GEF and EMF, and the GMF dia-
gramming functionality is based on this model. Although it is general in its
design, the notation model borrows some from GEF itself, similar to the tooling's
graphical definition model.
Figure 10-21 is a diagram of the notation model. As you can see, the View
class has an element reference to EObject . This is how the runtime provides a
link to the domain model (or “semantic” model, as it's commonly referred to in
the runtime documentation). EditPart s will find their model element using this
reference, although indirectly because the View object will be the GEF
EditPart 's “model” element. Typically, code such as ((View) editPart.
getModel()).getElement() is used to access the underlying domain model
from an EditPart .
View is the central class in the notation model, as you can tell from Figure
10-21. It contains the reference to the domain model element being represented
and also does the following:

Acts as the super type for Diagram , Node , and Edge

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Maintains a containment reference to children Node s (transient and
persistent)

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