CS 4773 Object Oriented Systems Spring 2005 Problem Fixed

The versions 05_01a and 05_01b would not let you change a session more than once. The problem was with the code in getLine which, when called with second parameter true, would call protect.lock() twice. Since releaseLock only released the lock once, protect was still locked.

I fixed the problem by moving the second call to protect.lock() up two lines in getLine so that the second call was inside the else. It is now at line 202 in EditorFile.

There were a number of false starts in trying to locate this bug.

• It seemed that the insertat command could be called more than once, indicating that the problem was in the normalkey command.
• insertat worked because it (incorrectly) calls the old version of getLine with only one parameter and therefore never locks the file.
• insertat should have failed when it called replaceLine since it never locked the file.
• replaceLine in EditorFile (incorrectly) does not check the lock, unlike removeLine or insertLine.

Also, remove any extra calls to logDebug that you no longer need, as these make it hard to find the important debugging messages.

Steve Robbins