Adding transactions info to mdr events

Martin, please review this proposal. Please tell me, if you agree. If
yes I will open an issue.



It's seems to be common sense that Undo/Redo management should be
implemented on top of JMI+events. The UndoManager should listen on
repository change events.

Furthermore undo/redo should respect transaction integrity.

But currently the MDR events do not inform about transactions at
all. Hence I propose:

1) Add to interface MDRChangeEvent the method:

   MDRTransaction getTransaction(); 

which returns the innermost transaction performing the change.

The interface MDRTransaction consists solely of the method:

  public interface MDRTransaction {
    MDRTransaction getParent();
  }

returning the enclosing transaction or null.


2) Add a new event type:

  public class TransactionEvent extends MDRChangeEvent {
     public static int EVENT_TRANSACTION_START     = ..;
     public static int EVENT_TRANSACTION_COMMIT    = ..;
     public static int EVENT_TRANSACTION_ROLLBACK  = ..;

     ...

     public int getType() {
       ...
     }
  }

Only listeners on the MDRepository are informed about transaction
events.



-- 
Holger Krug
[email protected]