public Class TempFileCache

Create the temp directory in tmpRootDir. To do this, we create a temp file with a ".tmp" extension, and then create a directory of the same name but without the ".tmp". The temp file, directory, and all files in the directory will be reaped the next time this is started. We avoid deleteOnExit, because it doesn't work reliably.

Called by the Reaper thread to delete old temp directories Only one of these threads will run per JVM invocation.

This method is called by the static initializer to create / initialize the temp root directory that will hold the temp directories for this instance of the JVM. This is done as follows: 1. Synchronize on a global lock. Note that for this purpose we will use System.out in the absence of a true global lock facility. We are careful not to hold this lock too long. The global lock is claimed in the static initializer block, calling this method! 2. Check for the existence of the "jnlp.jogamp.tmp.cache.root" system property. a. If set, then some other thread in a different ClassLoader has already created the tmpRootDir, so we just need to use it. The remaining steps are skipped. However, we check the existence of the tmpRootDir and if non existent, we assume a new launch and continue. b. If not set, then we are the first thread in this JVM to run, and we need to create the the tmpRootDir. 3. Create the tmpRootDir, along with the appropriate locks. Note that we perform the operations in the following order, prior to creating tmpRootDir itself, to work around the fact that the file creation and file lock steps are not atomic, and we need to ensure that a newly-created tmpRootDir isn't reaped by a concurrently running JVM. create jlnNNNN.tmp using File.createTempFile() lock jlnNNNN.tmp create jlnNNNN.lck while holding the lock on the .tmp file lock jlnNNNN.lck Since the Reaper thread will enumerate the list of *.lck files before starting, we can guarantee that if there exists a *.lck file for an active process, then the corresponding *.tmp file is locked by that active process. This guarantee lets us avoid reaping an active process' files. 4. Set the "jnlp.jogamp.tmp.cache.root" system property. 5. Add a shutdown hook to cleanup jlnNNNN.lck and jlnNNNN.tmp. We don't actually expect that this shutdown hook will ever be called, but the act of doing this, ensures that the locks never get garbage-collected, which is necessary for correct behavior when the first ClassLoader is later unloaded, while subsequent Applets are still running. 6. Start the Reaper thread to cleanup old installations.

Remove the specified file or directory. If "path" is a directory, then recursively remove all entries, then remove the directory itself.