MQL

Rule sets are used to define model transformations and to launch text generations. Rule sets are written in MQL (Model Query Language).

MQL has been designed with one primary goal: to allow the user to focus on the semantics of the model transformation instead of programmatic details. Here are some benefits:

• You do not have to cast, since it is a dynamic language.
• You do not have to define 'if' statements to test null values.
• You do not have to define 'for' loops to iterate over a collection of objects.

MQL is also used as an expression language for text templates statements.

Here is an example of ruleset that generates a Java source file for each Class contained in a UML 2.1 model:

package com.mycompany.example;

// expects a loaded UML 2.1 model as input
public ruleset GenerateAllJavaClasses(in model : uml21) {

    public rule generate() {
    
        // loop on each Class of the UML 2.1 model
        foreach (class in model.getInstances("Class")) {
        
            // calls the text template GenerateJavaClass
            $GenerateJavaClass(class);
        }
    }
}