load scriptlet-class in a package

[2002 JI Open Discussion]

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