I can try to take a look at it, but if I understand correctly, the problem with the Java emitter is that there is no standard for how a Java compiler classes file creation, which means that the emitter needs to be different for every Java compiler.
Which JDK do you use? V/R, William On Fri, Aug 1, 2014 at 5:49 PM, Kenny, Jason L <[email protected]> wrote: > We just updated in Parts trunk the Java tool. I believe it a few tweak > based on the standard Scons tools. The note I have on this fix is “Fixed > Java tool emitter to correctly handle derived targets.” > > > > You might want to look at it and see if it helps at all and is work > grabbing into SCons. > > > > Here is a link the SVN file online.. > http://parts.tigris.org/source/browse/parts/trunk/parts/parts/tools/javac.py?revision=516&view=markup > > > > Jason > > > > *From:* Scons-dev [mailto:[email protected]] *On Behalf Of *William > Blevins > *Sent:* Friday, August 1, 2014 4:23 PM > *To:* SCons developer list > *Subject:* Re: [Scons-dev] Java Development > > > > SCons Java doesn't need to be that fancy, but I think the root problems > can be solved. The SCons java tool simply doesn't get the love that some of > the other tools get. > > > > I don't have the experience with the code base to know if my ideas are > workable, so I will need some guidance. > > > > On Thu, Jul 31, 2014 at 11:04 PM, Mark A. Flacy <[email protected]> > wrote: > > On Sunday, July 27, 2014 03:10:34 PM William Deegan wrote: > > William, > > On July 25, 2014 at 8:27:02 PM, William Blevins ([email protected]) > > wrote: > > > > Team, > > > > I want to get another thread going for SCons Java development. > > > > The SCons Java tool has a ton of error reports on Tigris including 7 > > priority 1 issues. At the moment, this tool doesn't stand a chance > against > > other Java competitors, and not because they are great tools. I frankly > > hate ANT. I have used Java support from SCons and it's seriously > painful; > > nothing like the C++ support. Some other developers have made statements > > like "No one outside SCons builds Java programs more complicated than > hello > > world." The SCons tool framework is great, and I would really like to > see > > the Java toolkit see some love. It has potential to be a hidden gem, > and I > > want help out with this, but I don't have the experience to do this on my > > own, so firstly I'd like to list some of the biggest hurdles to users > SCons > > Java. I'm not gonna try and propose any solutions at the moment. I just > > want to see if I can get the group thinking about the problems. > > > > 1. Adding resource files to a jar causes SCons > > segfault: http://scons.tigris.org/issues/show_bug.cgi?id=2550 > > > > I have firsthand experience with this bug. The only way I could figure > out > > how to workaround it was to make a separate jar just for resources. > > > > 2. Java emitter almost never gets the java output correct. > > > > One of the many things I hate about ANT is that ANT is stupid. It always > > executes a build even if code is up-to-date and I usually have to > > explicitly clean. SCons COULD resolve both problems if the emitters > > worked. The only way to get remotely consistent working build is to call > > Jar( 'buildDir' ) when everyone wants to do Jar( [ 'class1', ... > 'classN' ] > > ). > > > > 3. Dependencies: > > > > SCons does not automatically add classpath items as dependencies. Why > do I > > need to do this manually? This is what SCons does! It's the heart and > > soul! > > > > I believe this is because of item #6. > > > > 4. Consistency: > > > > Classpath tokens (among other items) do not behave the same as other > > builders. Example: I cannot use "#jar/item.jar" in the classpath without > > expanding via something like File(...).get_path(). > > > > 5. Interfaces: > > > > Java(...) parameters and internal handling aren't intuitive and only > handles > > sources = 'directory' correctly. It doesn't do lists of java files or > list > > of directories in a sane manner. > > http://scons.tigris.org/issues/show_bug.cgi?id=1772 > > > > Personally, I don't think that Java and Jar should be separate functions. > > How do you get to the classes then? What about Javah! I have an idea, > > but that's outside the scope of this rant. > > > > 6. Performance: > > > > The dependency structure for Java exposes class files in a way that > creates > > tons of false positives. > > > > SCons current: > > > > classes1 = Java(...) > > > > classes2 = Java(...) > > > > Depends( classes2, classes1 ) # O( N^2 ) dependency graph with tons of > false > > positives > > > > SCons if I have anything useful to say about it > > > > jar1 = Jar( classes1 ) > > > > jar2 = Jar( classes2 ) > > > > Depends( jar2, jar1 ) # O( 1 ) which obviously fails in parallel builds > > currently. > > > > I am currently data mining a production Java codebase to prove my point. > > Dirk and I have already discussed this issue somewhat; thanks Dirk :) > > > > This actually causes the Task Master thread to get blocked on large jars > > reducing parallel efficiency in builds to None. > > > > > > The main issue here (if I understand SCons’ internals enough) is that > > SCons’s doing all dependencies on a per file basis. For many types of > > builds that works fine. For Java (building jars, and other issues) and > some > > other types of builds, that’s very inefficient. > > > > There’s no “blob” of files where you have N inputs and M outputs, and > thus > > you get the N*M arcs in the graph. > > > > Currently the only similar but not really similar enough is the Dir() > Node > > type. But that has it’s own problems, which could be solved by a N*M > type > > node. > > > > > > > > Other Java issues could likely be resolved building on top of such a new > > Node type. > > > > Though resolving the anonymous and inner classes in a java file creating > > more than one class file and what it might be named is also still an > issue > > which the scanner and emitter try to solve by parsing the java files and > > figuring out the proper naming. This of course is not (as I understand > it) > > formally defined as part of the java language and thus is a per compiler > > implementation detail. > > In my opinion, you are wasting your time. > > The way java produces artifacts is so different from the model that SCons > "expects" that you are attempting to cram an elephant down a shrew's > throat. > (or attempting to feed a Great White shark with ants, if you prefer) to get > this to work. > > SCons works *great* when there's one output per input, especially when you > can > deduce the output name from the input name and little else. It also works > great when it is fairly cheap to determine what files a given file depends > upon. > > Sadly, neither of those conditions exist with java source. > > > Between 2003 and 2010, I developed and maintained a python based build tool > for a Java project that contained ~10K java source files. It would > analyse the > java source files to figure out the package-level compile dependencies and > then > send lists of files to be compiled as a unit to a persistent compile > server (in > fact, you could run multiple compile servers at once to get a large degree > of > parallelism). It would then analyze the generated class files to see if > the > total public/protected interface for the package changed, preventing > recompiles if all you did was change an implementation detail versus a > visible > method or attribute. > > You could also register various hooks against packages (such as run rmic) > if > the package compiled correctly. We did some funky stuff with > autogenerating > WSDL from java source and then generate client classes from the WSDL and > compiling those classes also. Almost all of that was data driven. It did > other neat stuff that I don't remember off the top of my head, but I've > got all > the source sitting around in various tla/hg repositories. > > Nobody uses it any more. Even me, and I thought about providing some it > in an > open source build tool. > > For our Windows users, it was faster to nuke the output directories and > recompile everything in one invocation of javac. (Well, 2 invocations since > some of the funky stuff was to use the .class files from the first compile > to > generate the wsdl and use *that* wsdl to generate java source as part of > the > second bulk compile.) Most of the time difference had to do with the way > the > python tool talked to the compile processes by sending the list of file > names > through a pipe to the other process and then flushing the pipe. The rest > had > to do with the time spent parsing the files (and I maintained a cache of > parsed > file information that contained the last mtime of the source files and > would not > process a file whose mtime was the same as what was recorded). > > For our Linux users (me, for one), it was not quite a wash to change the > behavior but the delta wasn't enough to worry about. > > I'm more than willing to discuss this and also to be proven wrong. > > -- > Mark A. Flacy > _______________________________________________ > Scons-dev mailing list > [email protected] > http://two.pairlist.net/mailman/listinfo/scons-dev > > > > _______________________________________________ > Scons-dev mailing list > [email protected] > http://two.pairlist.net/mailman/listinfo/scons-dev > >
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