How would you address the possibility of each project using a different
version of the same class file? The filenames and jar files are the same,
but the code is different.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Monday, August 13, 2001 12:35 PM
> To: [EMAIL PROTECTED]
> Subject: Re: people using jdk < 1.2?
>
>
>
> One more thought on the classes data structure and I'll shut up. ;-)
> It would be nice if the data extracted from common jars could
> be shared
> across projects. That is, JDE shouldn't keep a separate list of the
> classes in rt.jar for each project a user has open. Assuming that
> the map approach is adopted, this would basically amount to keeping a
> collection of maps (one per classpath entry) and sharing items in that
> collection across projects. This would require putting a dirty flag
> on each map instead of on the project's collection of maps.
>
> Javier and Paul - please let me know if you want help with
> any of this.
>
> Eric
>
> In message <010301c12408$532e5c10$4173d490@kinnucanp>, "Paul
> Kinnucan" writes:
> : Hi All,
> :
> : Unless there are any strong objections, I'd like to adopt
> Eric's suggestion
> : and make JDK 1.2 a requirement for the JDE, beginning with
> JDE - 2.2.9beta1.
> : (I have frozen JDE-2.2.8 and plan to release it shortly.)
> I believe it's
> : possible to use JDK 1.2+ to develop for JDK <1.2 anyway by
> not using JDK
> : >1.1 and by using the JDK 1.1 cross-compile option.
> :
> : BTW, thanks, Eric, for taking the time to do a performance
> review of the
> : JDE's Java code and make specific recommendations for improving the
> : performance. Your recommendations are excellent. Javier
> Lopez has already
> : sent me updates that implement some of them and I plan to
> include Javier's
> : updates in JDE 2.2.9beta1. It will be interesting to see if
> they make a
> : perceptible difference.
> :
> : - Paul
> :
> : ----- Original Message -----
> : From: <[EMAIL PROTECTED]>
> : To: "Kevin A. Burton" <[EMAIL PROTECTED]>
> : Cc: <[EMAIL PROTECTED]>
> : Sent: Monday, August 13, 2001 9:06 AM
> : Subject: Re: people using jdk < 1.2?
> :
> :
> : >
> : > [java 1 vs. java 2 comments]
> : >
> : > : Has there been any documentation out about this? I
> don't see why using
> : the
> : > : Collections API would increase performance.
> : >
> : > Yes, a number of articles and book chapters have been
> written about
> : > the cost of acquiring the synchronization lock on java
> objects. Since
> : > every method on Vector/Hashtable is synchronized, and
> since these were
> : > frequently used classes in JDK < 1.2, they quickly become
> performance
> : > bottlenecks. The java 2 collections are not synchronized
> by default
> : > and so do not suffer from this particular shortcoming.
> : >
> : > The second performance problem I noticed is algorithmic in nature.
> : > The JDE builds a list of all compiled classes in your project (>
> : > 5,000 in the JDK base -- not counting i18n and so forth -- alone).
> : > When determining which class to import, it does a linear
> scan on this
> : > list. Clearly it would be faster to sort the list and
> then use binary
> : > searches for lookups.
> : >
> : > Other obvious, low hanging fruit include using
> StringBuffer.append()
> : > instead of String concatenation inside of loops, and
> removing unnecessary
> : > synchronized method calls in those same loops.
> : >
> : > An alternative to using a sort/search loop algorithm
> would be to replace
> : > the list data structure with a Map. In the current
> implementation, the
> : > list is comprised of fully qualified classnames. The
> search looks for
> : > the qualified classname only (the `Map' in
> `java.util.Map'). Clearly one
> : > could precompute the `Map' string when building the data
> structure and
> : > turn the search loop into a simple hash lookup that
> resolves to either
> : > a single String (`Map' -> `java.util.Map') or a List of
> Strings (`List'
> : > -> {`java.util.List', `java.awt.List'}).
> : >
> : > Eric
> : >
> :
>
