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< MoDisco‎ | Components‎ | FacetManager
Revision as of 06:31, 22 January 2010 by (Talk | contribs) (Rename "role" to "facet")

DEPRECATED use Template:MoDiscoTabs and Template:MoDiscoTab as explain here : Wiki Template for MoDisco

How to create a model facet set

The first step is to create a MoDisco project.

The second step is to create a query set. This query set will store boolean queries indicating if an object conforms to a facet.

Right-click on the MoDisco project and select the "New > Other ..." button.

MoDisco Role newRoleSet 001.gif

Select "Facet Model" and press the "Next" button

MoDisco Role newRoleSet 002.gif

Choose a name for your model facet set (My.facetSet in the example) and press "Next".

MoDisco Role newRoleSet 003.gif

Select "FacetSet" in the "Model Object" list and press "Finish"

MoDisco Role newRoleSet 004.gif

MoDisco Role newRoleSet 005.gif

Open the "My.facetSet" file and open the "Properties View"

MoDisco Role newRoleSet 006.gif

Set the name of the facet set and make sure that the facet set name is the same as the containing file name ("My" in the example). The nsURI and prefix must also be filled.

MoDisco Role newRoleSet 007.gif

Load the resources containing the meta-model extended by the facet set. To load a meta-model resource the user must use the "Load meta-model resource" action.

MoDisco Role newRoleSet 008.gif

In this example, we choose to use the Java meta-model.

MoDisco Role newRoleSet 009.gif

Fill the "Extended package" field with the ePackages containing the virtually extended meta-model.

MoDisco Role newRoleSet 010.gif

Right click on the FacetSet element and choose the "New Child > Facet" action to create a facet.

MoDisco Role newRoleSet 011.gif

Set the facet name and the class that the facet will extend.

MoDisco Role newRoleSet 012.gif

To specify how to know if an object conforms to a facet, we have to provide a boolean query. To provide this query we have to load the model containing its description.

MoDisco Role newRoleSet 013.gif

The query has to be referred to using the MoDisco protocol: "modisco:/query/<querySetName>". In the example, we use the "My" query set.

MoDisco Role newRoleSet 014.gif

Once the query set resource is referenced, we just have to select the query describing the facet. In the example this query is named "isAbstract".

MoDisco Role newRoleSet 015.gif

At this step, if we save the model, the "red cross" should disappear from the file icon. This means that the facet set model is now valid.

MoDisco Role newRoleSet 016.gif

If the facet has specific attributes or references which can be calculated, we can declare them. In this example, we will declare an attribute indicating the number of abstract methods contained in the abstract class. To create a new facet attribute right-click on the facet element and select the "New Child > FacetAttribute" item.

MoDisco Role newRoleSet 017.gif

The attribute's type and name must be set. The "Value Query" field must be filled with a reference to a query which is used to calculate the attribute's value. This query must have the same type as the attribute and be applicable to the virtually extended class.

MoDisco Role newRoleSet 018.gif

The facet set is now ready to be used.

How to consult the MoDisco facet set catalog through the UI

If a facet set model is valid, it is registered in the facet set catalog. To consult the facet set catalog, we can use the "Facet Set" view.

To open this view select "Windows > Show view > Other ..." in the menu bar and choose "Facet Set" in the list.

MoDisco Role newRoleSet 019.gif File:MoDisco Role newRoleSet 020.gif

The "Facet set" view presents the available facet sets and their facets. For each facet set the location of its description model is pointed out.

MoDisco Role newRoleSet 021.gif

How to programmatically use the MoDisco facet set catalog

Here is an example of using the MoDisco facet API. For more information please refer to the JavaDoc.

import org.eclipse.emf.ecore.EObject;
import org.eclipse.gmt.modisco.infra.query.core.exception.ModelQueryException;
import org.eclipse.gmt.modisco.infra.facet.Facet;
import org.eclipse.gmt.modisco.infra.facet.FacetSet;
import org.eclipse.gmt.modisco.infra.facet.core.FacetSetCatalog;
import org.eclipse.gmt.modisco.infra.facet.core.exception.ModiscoFacetException;

public class Example {

	public Integer getNbAbstractMethod(EObject eObject)
			throws ModelQueryException, ModiscoFacetException {
		FacetSet facetSet = FacetSetCatalog.getSingleton().getFacetSet("My");
		FacetContext context = new FacetContext();
		Facet facet = facetSet.getFacet("AbstractClassDeclaration");
		if (context.isInstance(eObject, facet)) {
			Object object = context.get(eObject, facet
			if (object instanceof Integer) {
				Integer nbAbstractMethod = (Integer) object;
				return nbAbstractMethod;
		return null;

Facet Meta-model Description

MoDisco Role metamodel.png

The facet meta-model extends the ecore meta-model and uses the query meta-model.

A FacetSet is a kind of EPackage. A FacetSet contains facets through the eClassifier reference. A facet is a kind of EClass.

For a facet instance, the eSuperType reference must be set to specify which class the facet virtually extends.

The facet class has one specific reference: conditionQuery. The conditionQuery reference points to the ModelQuery class. The model queries pointed to by the conditionQuery reference must return a Boolean. Those queries are used to specify how to decide whether an instance conforms to a facet. If the conditionQuery is empty then all the instances of the class referred to by the facet instance through the eSuperType reference conform to this facet.

A facet contains facetAttributes and facetReferences through the eStructuralFeature reference. The FacetAttribute and FacetReference classes have a common super class: FacetStructuralFeature. The FacetStructuralFeature has one reference named valueQuery pointing to the ModelQuery class. The valueQuery is used to compute the facet structural feature value. The facetAttribute and facetReference must have the same type as the query they refer to.

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