CODEWITHSUNDEEP
javaibm-midrangerpglerpg
jax
jax

Reputation: 38643

Using String.format with RPGLE

I would like to interface RPGLE with String.format which takes variable length arguments or an array, I also want to pass numbers as well as strings, so I will be using format like "hello %s, you are %d years old". Can someone give me some advide on how to prototype this in RPGLE?

UPDATE

It seems that some people were confused with the quesion. To make things clear, I want to prototype the following in RPGLE. Note that the second argument to the method is a varargs parameter, so any number of arguments can be supplied! RPGLE definitely does not support this, but it does support *nopass so this my be helpful in achieving the result I need.

  String format = "|%1$-10s|%2$-10s|%3$-20s|\n";
  System.out.format(format, "FirstName", "Init.", "LastName");

  or

  String.format(format, "FirstName", "Init.", "LastName");

I am not interested in how I can format strings in RPGLE, I want to prototype a java method.

Upvotes: 2

Views: 2190

Answers (3)

Climb
Climb

Reputation: 1

I totally agree that we prefer using native RPGLE functions whenever possible. However, as RPGLE developers, we're also open to utilising any external functions as needed.

Here's an example that might be relevant to your situation, though I'm not sure if it directly addresses your case:

Step 1. Create a Java class with a method that accepts a format string and a varargs parameter:

public class StringFormatter {
    public static String formatString(String format, Object... args) {
        return String.format(format, args);
    }
}

Step 2. In the RPGLE program, define the prototype for the Java method. You'll need to use the *JAVA and *NOPASS options to handle the variable arguments.This prototype allows you to pass up to 10 arguments, which should be enough for most cases. If you need more, you can extend the prototype with additional arguments. And finally you can call the formatString method from your RPGLE program like below

dcl-pr formatString varchar(32767) extproc(*JAVA : 'StringFormatter' : 'formatString');
   format varchar(32767);
   arg1   varchar(32767) options(*nopass);
   arg2   varchar(32767) options(*nopass);
   arg3   varchar(32767) options(*nopass);
   arg4   varchar(32767) options(*nopass);
   arg5   varchar(32767) options(*nopass);
   arg6   varchar(32767) options(*nopass);
   arg7   varchar(32767) options(*nopass);
   arg8   varchar(32767) options(*nopass);
   arg9   varchar(32767) options(*nopass);
   arg10  varchar(32767) options(*nopass);
end-pr;

dcl-s result varchar(32767);

result = formatString('|%1$-10s|%2$-10s|%3$-20s|\n'
                     : 'FirstName'
                     : 'Init.'
                     : 'LastName');

dsply result;

*inlr = *on;

Upvotes: 0

David G
David G

Reputation: 4014

How about using message's to do the formatting ... they are quite powerful and the text is externalized (and CCSID aware).

You can use the QMHRTVM API to retrieve the formatted message.

When you're in RPG code, it's always faster to invoke native functionality than Java.

Upvotes: 4

Mike Wills
Mike Wills

Reputation: 21275

Is there a particular reason you want to use Java? The overhead of starting up a JVM can be killer on many applications. RPG itself can do that easily using concatenation.

/free
 resultString = 'hello ' + %trim(name) + ', you are ' + 
                %trim(%char(years)) + ' years old';
/end-free

Upvotes: 2

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