Promotion of Parts when Dropped: Design

Problem:

VCEPreSetCommand is responsible for the scoping of Java elements that are added to the JEM model.  It has four possible scopes:
GLOBAL_GLOBAL
This is an instance variable and it also has its own method that initializes and returns it
GLOBAL_LOCAL
This is an instance variable, but it is initialized in the method that initializes the parent
LOCAL
This is local to the method that uses the object
PROPERTY
There is no instance variable and it is a method argument

Right now the decision of the scope is hard coded.  For example, the code in VCEPresSetCommand right now hard codes AWT and SWT to scope in a particular way.


        protected int settingType(EObject property) {
                if (classAWTComponent.isInstance(property))
                        return GLOBAL_GLOBAL;                                // Hard code AWT components to be global and globally initialized (in their own getJavaBean() method)
                else if(classSWTShell != null && classSWTShell.isInstance(property))
                        return GLOBAL_GLOBAL;
                else if (classSWTControl != null && classSWTControl.isInstance(property))
                        return GLOBAL_LOCAL;                                // Hard code SWT controls to be globally declared and initialized in their parent method
                else
                        return PROPERTY;
        }

We need to make this more flexible.  For one thing It means the ve.java package has knowledge of AWT and SWT (which should be described just their respective jfc and swt plugins), and for another it means that other people like Canoo cannot leverage the logic.


Proposal:

Introduce an Enum property on org.eclipse.ve.internal.jcm.BeanFeatureDecorator called scope.
Introduce an Enum property on org.eclipse.ve.internal.jcm.BeanDecorator called scope.

This would look like:

  <!-- The enumeration for code generation scope. -->
  <eClassifiers xsi:type="ecore:EEnum" xmi:id="Scope" name="Scope" >
    <eLiterals name="global_global" value="2"/>  
    <eLiterals name="global_local" value="3"/>
    <eLiterals name="local" value="1"/>
    <eLiterals name="property" value="0"/>
  </eClassifiers>
 

The logic in VCEPreSetCommand would be to check the BeanDecorator scope of the newValue and use this.  If it wasn't set then the BeanFeatureDecorator of the feature would be used.  If neither were present then the default would be PROPERTY;

Examples:

All AWT components are scoped in their own method
       -        java/awt/Component.override

    <addedEObjects xsi:type="org.eclipse.ve.internal.jcm:BeanDecorator"
        beanProxyClassName="org.eclipse.ve.jfc/org.eclipse.ve.internal.jfc.core.ComponentProxyAdapter"
        scope="global_global"/>

JLabel wants to be scoped in the method of the parent that declares it
       -        javax/swing/JLabel.override

   <addedEObjects xsi:type="org.eclipse.ve.internal.jcm:BeanDecorator" scope="local"/>

All SWT controls should be scoped in the parent method but an instance var in the class
        -        org/eclipse/swt/widgets/Control.override

    <addedEObjects xsi:type="org.eclipse.ve.internal.jcm:BeanDecorator"
        beanProxyClassName="org.eclipse.ve.swt/org.eclipse.ve.internal.swt.ControlProxyAdapter"
        scope="global_local"/>

except for SWT Composites that always want to be in their own method
        -        org/eclipse/swt/widgets/Composite.override

    <addedEObjects xsi:type="org.eclipse.ve.internal.jcm:BeanDecorator"  
      beanProxyClassName="org.eclipse.ve.swt/org.eclipse.ve.internal.swt.CompositeProxyAdapter"
        scope="global_global"/>

The default for everyone who doesn't have a scope is "property".  For anyone else who has their own custom parent/child relationship they can override the scope on a per class or per relationship basis.

Thanks,

Joe and Rich