Chapter 4 Extending your Models with Profiles

Transformation script tab

Generation history

Since a source object can be transformed and have several targets, you may have problems identifying the origin of an object, especially in the merge dialog box. The following mechanism is used to help identify the origin of an object:

If the source object is transformed into a single object Then the transformation is used as an internal identifier of the target object.

If the source object is transformed into several objects Then you can define a specific tag to identify the result of transformation. You should use only alphanumeric characters, and we recommend that you use a "stable" value such as a stereotype, which will not be modified during repetitive generations.

For example, OOM1 contains the class Customer, to which you apply a transformation script to create an EJB. Two new classes are created from the source class, one for the home interface, and one for the remote interface. In the transformation script, you should assign a tag "home" for the home interface, and "remote" for the remote interface. The tag is displayed between <> signs in the Version Info tab of an object, beside the source object.

In the following example, the tag mechanism is used to identify the classes attached to a component:

 'setting tag for all classes attached to component      
   for each Clss in myComponent.Classes
      if clss <> obj then   
         trfm.SetSource obj,Clss," GenatedFromEJB"+ obj.name +"target" +Clss.Name
         For each ope in clss.Operations        
           if Ope.Name = Clss.Code Then 'then it is a constructor _Bean operation
              trfm.SetSource obj,Ope," GenatedFromEJB"+ obj.name +"target" +Ope.Name
           end if   
           if Ope.Name = Clss.Name Then 'then it is a constructor operation
              trfm.SetSource obj,Ope," GenatedFromEJB"+ obj.name +"target" +Ope.Name
           end if   
           if Ope.name = "equals" Then 'then it is an equals operation and should be tagged
              trfm.SetSource obj,Ope," GenatedFromEJB"+ obj.name +"target" +Ope.Name
           end if
         next
     end if  
   next

Script checks

Transformation scripts do not require as many checks as standard scripts, which require that you verify the content of a model in order to avoid errors, because transformations are always implemented in a temporary model where there is no existing object. The temporary model is merged with the generation target model if the Preserve modification option is selected during update.

If you create a transformation using an existing script, you can remove these controls.

Internal transformation object

Internal transformation objects do not appear in the PowerDesigner interface; they are created as temporary objects passed to the script so that the user can access the helper functions, and also to record the execution of a sequence of transformations in order to be able to execute them later.

Internal transformation objects are preserved when the transformations are used by the Apply Transformations feature or in a menu, so that when you update a model (regenerate) in which these kind of transformations have been executed, the transformations can be re-executed in the source model in order to maintain an equality between the source and the target model.

For example, CDM1 contains an entity A. You generate an OOM from CDM1 and class B is created. You apply some transformations to class B in OOM1 in order to create class C. When you re-generate CDM1 and update OOM1, class B will be generated from entity A but class C is missing in the generated model, and shows as a difference in the merge dialog box. However, thanks to the internal transformation objects, the transformations which were executed in the generated OOM are re-executed and you obtain class C and the models to be merged are more similar than before.

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