trigger or listener?

We want to have a Postgres database on a Linux web server updated when 
the corresponding record on the AS/400 changes.  We are thinking:

a) DB trigger on the '400 that wakes up when the record is changed and 
calls a Java program (also on the '400), passing the needed parameters 
as arguments to main(); the Java program uses JDBC to update the 
Postgres database on the Linux server.  Pro: probably easy to set up, 
Con: new process spawned for each write.

b) A Java program that runs all the time and listens for changes on the 
AS/400 database using something like FileListener from the JT400 
toolbox (haven't researched this yet); he would do the same as a).  
Pro: single program, Con: don't know if it's possible.

What recommendations would you guys make?  We are hoping to get away 
without modifying the program that is actually making the changes on 
the '400.  We are not talking about a huge number of records here; 
probably a couple hundred every few hours.