Handling Java exceptions (JDBC application )

I'm trying to drag myself into the 21st century when it comes to coding,
partly though calling all of my old C code through Python (going OK so
far) and also by using JDBC along with the ODBC stuff I already know. And
what better way to do that than through Jython to help leverage my
limited knowledge of Java.

It didn't take me long to hit a problem :-)

The JDBC driver is for the Pervasive.SQL database and my code performs a
simple table query without any problem. I wanted to handle the exceptions
that might be returned from the driver in a helpful fashion to the user
but my attempts at catching them seem to be failing. A slightly cut-down
version of the code so far:

------
import com.ziclix.python.sql as sql
import sys
from java import net

DSN = "jdbc:pervasive://%s" % (sys.argv[1],)
    
try:
    Id = int(sys.argv[2])   # this can raise a ValueError exception
    db = sql.zxJDBC.connect(DSN, None, None,
"com.pervasive.jdbc.v2.Driver")    # this can raise a MalformedURLException
    cursor = db.cursor()

    queryString = "SELECT prnqueue_index_no, report_filename,
print_device, omega_user_name, error_code FROM sys_prnqueue_table ORDER
BY prnqueue_index_no"

    cursor.execute(queryString)

    # need to process the rows here
        
    cursor.close()
    db.close()
     
except net.MalformedURLException:
    print "Error: Invalid or non-existent datasource name"
except ValueError:
    print "Error: Incorrect parameter type used"
except Exception, e:
    print "Pervasive.SQL error:"
    print e
-------

By deliberately passing an illegal second parameter I can raise the
ValueError exception, but if I specify an incorrect datasource name (DSN)
the exception is not caught by net.MalformedURLException, but by the last
except (the one that prints "Pervasive.SQL error:").

If I raise the MalformedURLException myself with the following test code
then it works and "Malformed URL" gets printed:

--------
from java import net

try:
           for i in range(10):
                      if(i==8):
                                 raise net.MalformedURLException
                      else:
                                 print i
                
except net.MalformedURLException:
           print "Malformed URL"
        
except Exception, e:
           print e
--------

So....a Java exception returned from Java code is handled differently
than one raised within Jython? I've been Googling and paging through my
Jython Essentials book, but I'm missing something.

Help!

Neil





-------------------------------------------------------
This SF.Net email is sponsored by Yahoo.
Introducing Yahoo! Search Developer Network - Create apps using Yahoo!
Search APIs Find out how you can build Yahoo! directly into your own
Applications - visit http://developer.yahoo.net/?fr=offad-ysdn-ostg-q22005