[Objectbridge-developers] Reader/Writer Locks and other such stuff

[Dixon-Peugh, D. <Dav...@tp...>]

Good evening.

I've been doing some work on ObJectBridge, and have made some
further progress.  First a note on CVS.

When I tried to connect to CVS from home, I was unable to get
to the "ojb" directory of ObJectBridge.  I dropped some work into
the "objectbridge" directory.  I've moved just about everything
that has been updated to "objectbridge" from "ojb" (as I can
get to both at work, but only one at home.)

Now, as for the changes:

ojb.server.ReaderWriterLock -

This class implements a ReaderWriterLock on an object.  Unfortunately,
we cannot enforce this lock (its up to the user to do that.)  There are
basically a couple of APIs:
	read( Trans )
	write( Trans )
	upgrade( Trans )
	release( Trans )

Right now, the locks are maintained in the TransactionImpl (wrong place,
should probably be in a LockManager or such.)

ojb.server.ObjectTransactionWrapper - 

This class maintains the state of a persistent object at the begining and
end of a transaction.  When the wrapper is aborted, the persistent fields
of the object are restored to what they were at the begining of the 
transaction.  

ojb.server.TransactionImpl -

This class has been modified to use the Reader/Writer locks as apropriate.
It has also been modified to build ObjectTransactionWrapper around all
objects
that a WRITE lock is acquired on.

It has been modified to have ObjectTransactionWrapper commit/abort where
apropriate.

ojb.server.TransactionAware -

This is an interface that the end-user can implement.  With the
TransactionAware iface,
you can kill a transaction which involves your object.  You can also clean
up in
the event of an abort.

Share and Enjoy!

David.