[Openjnlp-devel] Updated Launcher and caching

[Kevin H. <ke...@na...>]

I meant to post this info a few days ago...

OpenJNLP has been tweaked with a much improved self-updating launcher. 
Here's a breakdown of what's new:

FileCachedResource is no longer an inner class, and can be used directly 
without anything else. The constructor simply needs a Reference and a 
directory (File object) to store the resource in. You can also supply a 
separate directory for the place to expand native libs. If the lib dir 
is null no expansion will be done. CachedResource.update() is now public 
and can be called at any time to update the resource in the cache.

The external launcher now only checks to update itself once. The check 
for an update is done from Launcher.launchExternal() which still always 
calls Launcher.updateLauncher(), but updateLauncher() will only do the 
update once.

updateLauncher() tries to update the launcher jars from the installed 
application itself, based on where the jars are supposed to be (from the 
launcher.properties file). If that location can't be accessed then 
updateLauncher() will use the launcher network home for the jars. This 
is set in launcher.properties to <http://openjnlp.nanode.org/launcher>. 
I've got nearly-current files out there so network updating is 
functional.

The updating is done using the new FileCachedResource for each launcher 
jar. There were a number of problems I found in the original 
CachedResource.update() code which have been fixed. In addition to this 
FileCachedResource.update() will also use File.setLastModified() to set 
the last modified date of the cache file to whatever the date on the 
source (server side) is. I also had to tweak 
CachedResource.getRemoteLastModified() for special checking of file URLs 
because Sun's "file:" URLStreamHandler is poorly implemented.

Finally, the build process now combines all of the xml-related jars into 
a single "openjnlp-extra.jar". The purpose of this is to avoid weird 
version naming issues that might arise (such as with NanoXML, for 
example). The idea behind "openjnlp-extra.jar" is it will contain any 
third-party code that the launcher needs. The ant build uses the <jlink> 
task to combine jars, which is part of the ant optional tasks jar, so 
make sure and have those installed if building with ant.