Example queries on Modelio models

This article shows several example queries on Modelio projects. The Modelio model driver does not use the XMI export in Modelio: instead, it parses .exml files directly (which might be contained in .ramc files) and understands metamodels described in Modelio metamodel_descriptor.xml files. (To obtain one, download the source code for your Modelio version and search within it. Here is a copy of the one used for Modelio 3.6.)

All the queries are written in the Epsilon Object Language, and assume that the toy Zoo Modelio project has been indexed. The queries are based on those in the XMI-based UML examples page. The underlying UML model looks like this:

To avoid ambiguity in type names, the default namespaces list in the query dialog should include modelio://uml::statik.

All instances of a type

Returns the number of instances of "Class" in the index:

return Class.all.size;

Metamodel URI for the "Class" type

Returns the URI of the metamodel that contains the "Class" type (modelio://uml::statik):

return Model.types.selectOne(t|t.name = 'Class').metamodel.uri;

Reference slots in a type

Returns the reference slots in the type "Class":

return Model.types.select(t|t.name='Class').references;

Reference traversal

Returns the superclass of "Zebra" by navigating the "Parent" and "SuperType" associations present in the Modelio metamodel:

return Class.all
  .selectOne(c|c.Name='Zebra')
  .Parent.SuperType.Name;

Reverse reference traversal

Returns the subclasses of "Animal", using the revRefNav_ to navigate references in reverse:

return Class.all
  .selectOne(c|c.Name='Animal')
  .revRefNav_SuperType
  .revRefNav_Parent
  .Name;

Range queries with indexed or derived integer attributes

This example requires adding a derived attribute first:

• Metamodel URI: modelio://uml::statik
• Type Name: Class
• Attribute Name: ownedOperationCount
• Attribute Type: Integer
• isMany, isOrdered, isUnique: false
• Derivation Language: EOLQueryEngine
• Derivation Logic: return self.OwnedOperation.size;

After it has been added, this query will return the classes that have one or more operations:

return Class.all.select(c|c.ownedOperationCount > 0).Name;

Advanced example: loops, variables and custom operations

This query produces a sequence of >x, y pairs which indicate that y classes have more than x operations of their own:

var counts = Sequence {};
var i = 0;
var n = count(0);
while (n > 0) {
  counts.add(Sequence {">" + i, n});
  i = i + 1;
  n = count(i);
}

return counts;

operation count(n) {
  return Class.all.select(c|c.ownedOperationCount > n).size;
}