Calling a java program thru a trigger or a function in postgresql - Mailing list pgsql-patches

Here's a high-level overview of what I want to do:

1.  A record in a postgresql database is changed.
2.  If the change causes the data record to meet certain conditions based on
    Boolean logic, a database trigger will invoke a Java UDF.
3.  This Java UDF uses the JavaMail API to send an e-mail to a specified
    recipient.

The javamailing program is written separately and is running fine.

Can any one give me the following details :

1.  Where to place the java or class file for access.
2.  plz give me the exact create function statements.
3.  plz give me the exact create trigger statments.

             O R
Plz give me the code to satisfy my requirement.

Thanks in advance for ur help

venky