runtime report compilation

[2006 IR Open Dicussion]

By: Ming - ming80

runtime report compilation

2006-06-18 20:48

I sent an email to teodord@users.sourceforge.net about a week ago, and I still get no response until today. Anyway, here's what I wrote:

 

I've been using JasperReports for several months now, and it was

great, good job! :)

Anyway, there's a feature I just recently look for, and it seemed that

such feature is not yet available. Here's what happened:

 

One of my app requires that a report is compiled at runtime, and it

was not a problem, until recently, when I started using Java WebStart

to deploy my apps. The runtime compilation process failed with an

error message that some of JasperReports' class were not found. After

some "investigation" :) it turns out to be a problem with the

classpath & ClassLoader. Java WebStart (JWS) uses a ClassLoader other

than the System ClassLoader (which loads class files from disk), and

therefore it doesn't depend on any classpath. After dumping the

content of java.class.path system property to the console, I found out

that the only .jar referenced by the classpath was the one that

belongs to JWS, none of my app's .jar (including JasperReports') was

mentioned there. Changing the classpath or the java.class.path

property won't work either since my app's jar files is stored in JWS's

cache, and referring to them by hand (hardcoded in the app) is

certainly not a good practice (It will nullifies program portability

since the JWS cache can be relocated anywhere by the user). I came to

a conclusion that what I need is a runtime compiler that does not

depend on any classpath, and therefore accepts ClassLoader other than

the default System ClassLoader (which depends on classpath). In the

"language" of OOP, what I'm looking for is an implementation of the

JRCompiler interface that has a constructor with a signature similar

to this: JRCompiler(ClassLoader loader) instead of JRCompiler(String

classpath). I was wondering if I could see this implemented

in the future release of JasperReport :)