Traceability between an EMF Java model and the corresponding source code

MoDisco 0.9M4 has been released this week with Eclipse Indigo M4.

One of the new interesting features is the traceability between an EMF model created from the reverse-engineering of a Java application and the corresponding source code.

It allows to directly navigate from elements of the Java model in the MoDisco Model Browser to the corresponding code fragment in a Java editor.

This feature is provided by a new Java discoverer which can be executed with the MoDisco menu "Discover Java and Inventory model from Java source code" available on a Java project.

This discoverer automatically creates three EMF models:

• a Java model describing the content of the source code: it is the model created by the basic Java discoverer.
• a KDM Inventory model describing the structure of the Java project (all the files and folders).
• a traceability model containing relations between the Java model elements and source code fragments

If you need to know more about these models, you can read the documentation of the discoverer.

When you launch the discoverer on a java project, the traceability model is automatically opened in the MoDisco model browser. 

To activate the synchronization with the Java source code editor, you need to activate the "Synchronize with source code option". 

Now, when you click on a model element in the model browser, the corresponding source code is automatically highlighted in the Java source code editor (otherwise, the double-click on an element opens the property view).

How to create an EMF model from a Java application ?

Is it possible to reuse EMF-based tools with Java source code ? Yes if you have your Java source code translated into an EMF model.

This is the aim of the Java component provided by MoDisco. This component is composed of a ECore definition of a java application and a discoverer which creates EMF models from an EClipse project containing Java source code.

The ECore definition declares all the concepts of the Java language : Package, ClassDeclaration, MethodDeclaration, Parameters, VariableDeclaration, IfStatement, Assignment, CastExpression, LineComment, ...

To create an EMF model using this metamodel, select your project and right-click on the menu "MoDisco>Discover Java model from Java project...". A wizard appears to select the analysis options :

• You can extend the analysis to dependencies (the JAR used by the project).
• You can use an incremental mode if you need to optimize the memory usage
• You can limit the analysis to declaration members if you don't need a model of the instructions contained within the methods
• You can use a filter to exclude Java classes during the analysis

The result is an EMF model which can be opened with the EMF reflexive editor or with the MoDisco generic browser. This browser allows accessing directly to instances of a specific class (for example all the MethodDeclarations) and navigating through all the references (composed or not).

This model can be used with other EMF-based tools to check architectural or coding norms, to generate other models (UML or Domain-Specific) or to regenerate an other application (if you modify the Java model, MoDisco provides templates to regenerate Java source code).