The following program shows how to create and manipulate Java objects from within an RPG program.
The example will take a string containing the text ‘ hello ’ and remove the trailing and leading blanks using the java String method trim.
*Call a Java program from RPG
h dftactgrp(*no) actgrp(*caller)
*Declare a variable str - Java class type String
D str S O CLASS(*JAVA:'java.lang.String')
//Prototype for creating a String object
D makestring PR O EXTPROC(*JAVA:
D 'java.lang.String':
D *CONSTRUCTOR)
D CLASS(*JAVA:'java.lang.String')
D parm 65535A CONST VARYING
* Prototype the String method getBytes which converts a String to a byte
* array. We can then store this byte array in an alpha field.
*
D getBytes PR 65535A EXTPROC(*JAVA:
D 'java.lang.String':
D 'getBytes') VARYING
*
* Prototype the String method trim. It doesn't take any parameters,
* but since it is not a static method, must be called using a String
* object.
*
D trimstring PR O EXTPROC(*JAVA:
D 'java.lang.String':
D 'trim')
D CLASS(*JAVA:'java.lang.String')
D fld S 10A INZ(' hello ') VARYING
/free
//Call the String constructor
str = makestring(fld);
//Trim the string by calling the Java String trim() method.
//We will reuse the str field to store the result.
str = trimstring(str);
//Convert the string back to a byte array and store it
//in fld. Fld now contains ‘hello ‘
fld = getBytes(str);
*inlr = *on;
return;
Calling Java from RPG
