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http://issues.apache.org/bugzilla/show_bug.cgi?id=36541 ------- Additional Comments From [EMAIL PROTECTED] 2005-09-08 15:14 ------- (In reply to comment #34) > No, because at this point I believe making sure that the HashMap does not get > corrupted (using syncs on put and remove) is enough to guarantee that the get > method doesn't enter an infinite loop (by returning null, or the result when > there's a problem - it will be unpredictable, but seems to me equivalent to > the > higher level concurrency issues if you mix and match reads/writes in the > webapp > for critical data without being careful). I understand the point that others are making for all access needing the same sychronization. I don't understand your logic that read/get don't need syncronization. The issue with the infinite loop read stems from the fact that two different threads access the map at the same time. One for read and one for write, while the writer is modifying the map it corrupted the pointers the reader is using to traverse the data structures and thus enters an infinite loop (due to the HashMap design, other collection classes can detect some situations and throw an exception for ConcurrentAccessException). This is because there is no synchrnozation between get/put operations. Only between puts. As I pointed out in the TC user mailing list, it would be possible to use a ReadWriteLock to allow threading of multiple readers to take place. But while there is one writer working on the Map you need to be sure no reader is using the map too. Introducing the ReadWriteLock might introduce an unwanted JDK5 dependancy, I think its a new JDK5 concurrency class ? It might also be slower than a regular synchronized lock. But without benchmarks we wont know. -- Configure bugmail: http://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
