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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
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Steve, Thanks for your reply. Here are some follow-on questions. > -----Original Message----- > From: Steve Emmerson [mailto:steve@xxxxxxxxxxxxxxxx] > Sent: Friday, January 25, 2002 12:54 PM > > Because the RendererVector field that was protected by the above > synchronization block is also accessed by other methods as > part of their > transactions, removal of the synchronization block runs the risk of > corrupting the invarients of the class. Java in a Nutshell, 3rd Edition, p. 54 says: "If only one thread ever accesses a data structure, there is no need to protect it with synchronized." So I'm still curious about when and why multiple threads (using the same or other methods) might simultaneously modify a single instance of DisplayImpl. I'm hoping synchronization may not be necessary in certain well-defined circumstances. For example, if I'm not using VisAD's distributed computing features, and I'm not doing any multi-threading in my application, is this synchronization unnecessary? > > What are the situations where mapslock could be accessed by > more than one > > thread? Is synchronization only necessary when doing > distributed computing > with RMI? If so, could we have an option in VisAD to turn > off support for > > distributed computing when we don't need it? Such an > option might be useful > > elsewhere as well. > > All VisAD Display-s have their own threads. Are these the only threads that access the DisplayImpl objects? How many are there for each Display? Is there somewhere I should look in the documentation or code to learn more about the thread structure of VisAD? Randall W. Simons Sandia National Laboratories
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