Re: Passing a Complex Object to RPG?

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

You could potentially call an RPG routine as a native method (JNI), and 
in that scenario, you could pass a Java object as a parameter. RPG could 
then call Java methods, or use APIs, to get data from the object.

The problem with JNI (aside from complexity) is that the Java code and 
RPG code will need to run in the same job on the same system.  And 
unless you use the 6.1 features for multi-threaded access to RPG, you'll 
have to serialize the RPG call.

By contrast, JT400 and stored procedures both use interprocess 
communications, and run the RPG code in a separate job.  They even allow 
you to call across the network from another system.  But the 
disadvantage there is that you can't possibly pass an object, since an 
object is data in the computers memory, and memory can't shared across 
different processes.  (Err... well, that's not entirely true... but in 
this scenario it can't.)

The normal way of doing this sort of thing outside the JNI arena is to 
encode the object in XML (or, less commonly, JSON) and pass it to the 
RPG, have the RPG work with the XML, then output a new XML that can be 
converted back into an object on the Java/PHP side.  There are standard 
protocols for this, including SOAP (simple object access protocol), 
CORBA, et al.


On 11/30/2010 4:33 PM, Paul Holm wrote:
> Is it possible to pass a complex object (Java or PHP) to RPG and have
> RPG invoke various methods on the object?  This could be either a Stored
> procedure call or a JT400 program call or any other means.
>
> If so, I see this giving us a way to generically pass input parameters
> and other business objects for validation or workflow and custom
> business logic without having to declare in/out for every single scenario.
>
> Thanks, Paul Holm