Re: [henshin-dev] Technical details for Henshin model migration

[Christian Krause <henshin.ck@xxxxxxxxx>]

Hi Felix,

I don't think it is a good idea to do the migration with Henshin, 
because you can't use reflection in Henshin.

In plain Java, the migration can be implemented with minimal effort. It 
could look like this:

// List of old model instances (dynamic!):
List<EObject> oldObjects;

// Map from old to new model elements:
Map<EObject,EObject> newElements = new HashMap();

// Create corresponding new elements:
for (EObject oldObj : oldObjects) {
    String type = oldObj.eClass().getName();
    if ("AmalgamationUnit".equals(type)) {
        continue;  // skip amalgamation units
    }
    EObject newObj = HenshinFactory.eINSTANCE.create(type);
    newElements.put(oldObj, newObj);
    // copy attributes from oldObj to newObj...
}

// now copy cross references (ignore amalgamation units)...

// update nested rules for all amalgamation units...

// Done!

> I planned to start as soon as the new model is fixed and support for 
> testing (i.e. executing) the transformed rules is available. We seem 
> to still be discussing a few interesting semantic aspects of rule 
> execution at the time. If the new model is considered final, I will 
> start by creating the transformation rules for henshin files and 
> testing them extensively to ensure perfect conversion of lots of 
> henshin files. This will be especially important, as correcting files 
> before or after transformation will be difficult. Having a couple of 
> rather complex henshin files which use henshin's current feature set 
> will likely increase the quality of automatic conversion due to better 
> testing. Since I do not have many henshin files using the full 
> spectrum of henshin's features, any help in obtaining more henshin 
> files for testing will be greatly appreciated.
> When this will be done, the diagram transformation and wizards can be 
> created.
>
> Felix