On Wed, 18 Dec 2013, Martin Scherer wrote:

Hi Andi,

do you suppose that adding to the classpath by runtime is possible via
python or a java workaround?

You can see the horrible kludge implemented in JCCEnv::setClassPath().
It is possible to modify the classpath at runtime.

I think it is very error prone if the user has to maintain his own
classpath and can not rely on jcc.

Yes, classpaths are very error prone.

Andi..


Best,
Martin


Am 04.11.2013 16:02, schrieb Andi Vajda (JIRA):

    [ 
https://issues.apache.org/jira/browse/PYLUCENE-28?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13812882#comment-13812882
 ]

Andi Vajda commented on PYLUCENE-28:
------------------------------------

A couple of comments. Your patch introduces a silent failure: if the second 
invocation of initVM() is made with different parameters (in particular, with a 
different classpath) people are going to be tearing their hair out with odd 
class loading errors because the 'second' classpath didn't take. Your patch 
should at least make sure that the classpath in the second invocation either 
matches the first or that the second classpath is forced into the existing VM 
(possible but hacky).

I didn't intend jcc to be used this way because of the one Java VM per process 
limitation and I thus consider your bug a feature request. It's a worthwhile 
feature nonetheless but it needs to be implemented more solidly.

Maybe a better way to support this would be to introduce a new entrypoint in cpp.py that 
takes a VMEnv. That way, there is no silent failure possible, the user "knows" 
what VMEnv they have and passed in. Or maybe the jcc() function could take an optional 
VMEnv parameter - and check that no VM configuration params are passed in via args (and 
error if there are) in that case ?


JCC reuses JVM instances in impl, if compile() is called twice.
---------------------------------------------------------------

                Key: PYLUCENE-28
                URL: https://issues.apache.org/jira/browse/PYLUCENE-28
            Project: PyLucene
         Issue Type: Improvement
        Environment: jcc-svn-head (2.18-pre)
           Reporter: Martin Scherer
           Priority: Blocker
             Labels: patch
        Attachments: jvm_instance_check.patch


If you import jcc.cpp to call compile yourself (a wrapped setup.py script to 
generate a wrapper on the fly, which seems to be a common use case), the 
current version complains about the JVM already being initialized before.
The patch first checks for a running instance and creates one, if none is being 
found.
For myself, this is a blocker, since it raises otherwise.
Best,
Martin



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