load scriptlet-class in a package

By: k.Dammeier - rubia
load scriptlet-class in a package
2003-11-19 02:32
hello,

I want to load a scriptlet-class.
This scriptlet-class in the same package as the class which wants to need it for filling the report.
The package is in a jar-file.

I tried a lot of things, but the class is not loaded correctly.

( in a project without packages and jars, only with the scriptlet-class and the other class, I don't need to load the scriptlet-class.)

Can anybody help?

thanks a lot!




By: Fred Welland - fwelland
RE: load scriptlet-class in a package
2003-11-19 07:06
/** orginally sent to mail list; sorry for the dup **/

I actually had lots of class loading issues related to scriptlets and Jasper
0.5. In my case, my Jasper stuff was embedded in a WebApp, and the report and
scriptlet were uploaded via a browser and run by my AppServer (iPlanet 6).

I tinkered some with this and found that much of the class loading for JR
appears to be handled by dori.jasper.engine.util.JRClassLoader.

I am not a classloader guru , but it is not clear to me that this class loader
extension follows the java1.2 classloader delegation pattern the way that it
should (or at least the way I think it should). This may be my ignorance in
the area; rather that a fault in the class.

In the end, I modified JRClassLoader. If you trace thru the 'fill' of a
report, you'll find that ultimately the static method JRClassLoader.
loadClassForName() is invoked on the name specified via your Jasper XML file's
scriptletClass value. It appears that if this class is *not* in the the
CLASSPATH (the runtime classpath) then you will get class not found issues.

So what I did was to add a 'last' chance load block to this method. If the
defualt/normal class loading code fails to load the scriptlet class, my version
of JRClassLoader.loadClassForName() will try one final time with a
URLClassloader to load the class. In my case, the URLClassloader simply used
the file: protocol to load classes from a directory on my appserver where my
servlet puts the uploaded scriptlets.

This has worked for me/my web app very well; perhaps a similar technique will
help you.

FWIW: I was very reluctant to modify jasper code. My preference was to change
this behavior via extension or something, but I don't know that this is
possible the way Jasper uses the JRClassloader: it specifically, creates a
JRClassloader during fill time. Now if it used a factory approach for creating
a classloader (and the JRClassloader was abstract or the like); then it would
be easier to customize the creation of objects that behave like a JRClassloader
but have additional classloading symantics.

HTH,

Fred








By: Teodor Danciu - teodord
RE: load scriptlet-class in a package
2003-11-29 00:42

Hi,

You need to fully qualify the class name in the scriptletClass attribute like this:

scriptletClass="com.mycompany.mypackage.MyScriptletClass"

Have you already done so?
The JAR file is in the classpath, right?

What is the error you get and what version of JasperReports are you using?

Thank you,
Teodor