Dominique Devienne wrote:
This is indeed interesting. I do something quite similar for another purpose
(scans a JAR for all classes having a give static method signature, executes
all these methods, gathering the meta-info required, generate a XML file
then stuck into the JAR's META-INF directory).
Something I do is to restrict scanning classes to only those that match a
given patternset to speed things up (you often know which part of your
package tree to look things, or could use a naming convention to find things
faster). This makes the scanning quite a bit faster (we have big JARs).
All this to say that you specific use case if very useful, but the more
generic action all scanning the classes of a JAR and doing something that
ultimately updated the JAR somehow would be even more useful. Allowing to
plug over 'actions' rather than the default 'looking for services' would be
very very useful IMHO.
Easy change to make--I can make it a protected action (the actual
check).
What are your dependencies? BCEL? Do you load the actual classes (so need
dependent classes on the classpath)?
Standard JVM. I use JarFile to read the JAR contents, and
JarOutputStream to write the new JAR.
I construct a new URLClassLoader that uses the current classloader as
the parent, and loads the input JAR in as well. I then scan the
contents of the JAR only looking at the ".class" entries. I load the
class, and perform my checks on the class itself.
Thanks for sharing this with us. --DD
PS: BTW, I don't think you can edit the JAR in place...
Would be nice though. I guess we could make it something where you can
use a directory instead of the JAR. It would alter the scanning code
though.
Do you want me to post what I have?
