Business-level locking mistakes

[Anton Golovin]

 
 public void deleteRoom(int recNo) throws IOException {
 
        long cookie = 0;
 
        try {
            cookie = data.lock(recNo);
        } catch (RecordNotFoundException rnfEx) {
            throw new IOException(rnfEx.getMessage());
        }
 
        try {
            data.delete(recNo, cookie);
        } catch (SecurityException secEx) {
            try {
                data.unlock(recNo, cookie);
            } catch (SecurityException secEx2) {
            } catch (RecordNotFoundException rnfEx) {
            }
            throw new IOException(secEx.getMessage());
 
        } catch (RecordNotFoundException rnfEx) {
            try {
                data.unlock(recNo, cookie);
            } catch (SecurityException secEx) {
            } catch (RecordNotFoundException rnfEx2) {
            }
            throw new IOException(rnfEx.getMessage());
        }
 
        try {
            data.unlock(recNo, cookie);
        } catch (SecurityException secEx) {
        } catch (RecordNotFoundException rnfEx) {
        }
 
    }
 

Anything else may fail

[Mike Vess]

Why not use finally instead of calling unlock three times?

[Anton Golovin]

Originally posted by Mike Vess:
Why not use finally instead of calling unlock three times?

I agree. I forgot finally executes no matter what. Sorry.

[peter wooster]

Originally posted by Anton Golovin:
... code omitted ...
Anything else may fail

Why? If you got a RecordNotFoundException or SecurityException attempting the delete with the record locked, what is the chance that the unlock, which has the same pre-conditions, could possibly succeed? Either of these exceptions at this point in the business logic is fatal.

I close the server and suggest that the user might want to select a different server (or database) as the one she's using is toast.

[Anton Golovin]

Originally posted by peter wooster:


Why? If you got a RecordNotFoundException or SecurityException attempting the delete with the record locked, what is the chance that the unlock, which has the same pre-conditions, could possibly succeed? Either of these exceptions at this point in the business logic is fatal.

I close the server and suggest that the user might want to select a different server (or database) as the one she's using is toast.

True, very true. You know, this is just the jitters of waiting I was told the assessor is grading my exam, which (my thought), given 19 classes, could appear scored at any moment
[ October 06, 2004: Message edited by: Anton Golovin ]