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Why are lock methods required?

Millicent Bare

Joined: Feb 27, 2007
Posts: 2
In the URLyBird project, the requirements specify an interface that includes
lock(recNo), unlock(recNo), and isLocked(recNo).

The way I'm implementing things, I don't see why the lock methods are required.
Can someone please explain?

First, it looks like only update() and find() are even needed by the
application. Obviously these methods are synchronized so that the file
pointer is not disturbed while seeking/reading/writing. Now, assuming
update() always checks the "owner" field before overwriting, then I've
guaranteed not to overbook on top of another reservation. Therefore, why
is lock needed? My synchronized methods ensure only one update() runs at
a time anyway.

The other problem is that lock() doesn't have a parameter to specify the
client requesting the lock. I can't use thead information here because a
client can connect to any server thread.

Can someone help me, please?

Petr Hejl
Ranch Hand

Joined: Feb 26, 2006
Posts: 68
You are asking for something discussed for million times...
Try to search the forum.
I agree. Here's the link:
subject: Why are lock methods required?
It's not a secret anymore!