The gradle task I’ve partially listed at the end of the post is intended to read an eclipse classpath and copy the various jar files and other compile / runtime files necessary for building a project that I’m working on (whose build structure and process I have no control over, so please hold the “you’re doing it wrong” feedback).
I’ve gotten lots of different errors - NullPointerExceptions, ConcurrentModificationExceptions, IllegalStateException and probably others I can’t remember. I’ve tried both milestone-5 and milestone-3 (I’ve never had M5 succeed fully, but I’ve seen M3 get through the full list of files twice out of about 10 runs or so). I’ve tried with “-C rebuild”, I’ve tried deleting both $HOME/.gradle and the project .gradle cache directories (it actually seemed like M3 was more likely to actually finish after I’d cleaned out the caches, but nothing I can reproduce reliably).
So, my questions: * 1) the sheer variety of different kinds of exceptions indicates to me that this may be totally unsupported, is that because ** 1.1) parallel task execution is just not supported? ** 1.2) parallel task execution is supported, but I’m doing it wrong (i.e. using gpars to tall Task.execute() methods on different threads)? Is there a proper gradle API way to do this or something? * 2) It seems like it always fails in the up-to-date checking - is there some way I could skip that part with the aim of not constantly reading and writing to the gradle cache, thus skipping the contention issues? * 3) parallel execution aside, is the serial execution branch correct? i.e. creating the tasks via the Project.task() method and then calling their execute() method - is there a better or more “gradle”-ish way to do it? * 4) I’m very new to gradle and groovy, so I’m going crazy using different features and what-not - any feedback or recommendations you’d like to provide on better ways to do things would be cheerfully accepted 
task copyJarFiles() << {
File jcopyDestDir = new File(jcopyDest)
println "destination directory: [${jcopyDestDir}]"
println "libRootPath: [${libRootPath}]"
println "copyFromBaseDir: [${copyFromBaseDir}]"
List copyTasks = []
forEachLibEntryInEachClasspath {
eclipseLib ->
copyTasks << createCopyLibTask(eclipseLib.@path.text() as File, jcopyDestDir)
}
println "starting execution of ${copyTasks.size()} copy tasks in ${parallelCopy?"parallel":"serial"}"
if( parallelCopy ){
GParsPool.withPool {
copyTasks.eachParallel{ Copy copyTask ->
println "thread [${Thread.currentThread().name}] executing task [$copyTask.name]"
copyTask.execute()
}
}
}
else {
copyTasks.each{ it.execute() }
}
println "finised execution"
}
private Copy createCopyLibTask(File libPath, File jcopyDestDir) {
File libPathDir = libPath.parentFile
String libEntryDirStructure = libPathDir.path.substring(libRootPath.length())
File copyFromDir = getCopyFromDir(libPathDir, copyFromBaseDir, libEntryDirStructure)
assert copyFromDir.exists(): "[$copyFromDir] does not exist"
File copyToDir = new File(jcopyDestDir, libEntryDirStructure)
println "path to process: [$libPath], libPathDir: [$libPathDir]"
println "libEntryDirStructure: [$libEntryDirStructure]"
println "copyFromDir: [$copyFromDir]"
println "copyToDir: [$copyToDir]"
return task("copy lib jars $libPath", type: Copy) {
from copyFromDir
into copyToDir
include { currentFile -> isCompileRunFile(currentFile.file.name) }
eachFile { FileVisitDetails i -> println "${->name}: copying $i.file.name" }
}
}
Edit: maaaany edits to get the code listing right.
