How to reference multiple instances of the same Java object from PL/SQL?

Question

Dear all,
I'm experimenting with calling Java from PL/SQL.
My simple attempts work, which is calling public static [java] methods through PL/SQL wrappers from SQL (and PL/SQL). (See my example code below).
However it is the limitation of the public static methods that puzzels me.
I would like to do the following:
- from PL/SQL (in essence it needs to become a forms app) create one or more objects in the java realm
- from PL/SQL alter properties of a java object
- from PL/SQL call methods on a java object
However I fail to see how I can create multiple instances of an object and reference one particular object in the java realm through public static methods.
My current solution is the singleton pattern: of said java object I have only 1 copy, so I do not need to know a reference to it.
I can just assume that there will only ever be 1 of said object.
But I should be able to make more then 1 instance of an object.
To make it more specific:
- suppose I have the object car in the java realm
- from PL/SQL I want to create a car in the java realm
- from PL/SQL I need to give it license plates
- I need to start the engine of a scpecific car
However if I want more then 1 car then I need to be able to refrence them. How is this done?
Somehow I need to be able to execute the following in PL/SQL:
DECLARE
vMyCar_Porsche CAR;
vMyCar_Fiat CAR;
BEGIN
vMyCar_Porsche = new CAR();
vMyCar_Fiat = new CAR();
vMyCar_Porsche.setLicensePlates('FAST');
vMyCar_Porsche.startEngine();
vMyCar_Fiat.killEngine();
END;
Thanks in advance.
Best Regards,
Ruben
My current example code is the following:
JAVA:
===
CREATE OR REPLACE AND RESOLVE JAVA SOURCE NAMED CODAROUL."RMG/BO/RMG_OBJECT" as package RMG.BO;
public class RMG_OBJECT {
private static RMG_OBJECT instance = new RMGOBJECT();
private String rmgObjectNaam;
private RMG_OBJECT(){
this.rmgObjectNaam = "NonDetermined";
public static String GET_RMGOBJECT_NAAM () {
String toestand = null;
if (_instance == null) {toestand = "DOES NOT EXIST";} else { toestand = "EXISTS";};
System.out.println("instance : " + toestand);
System.out.println("object name is : " + _instance.rmgObjectNaam);
return _instance.rmgObjectNaam;
public static Integer SET_RMGOBJECT_NAAM (String IN)
try
_instance.rmgObjectNaam = IN;
return 1;
catch (Exception e)//catch
System.out.println("Other Exception: " + e.toString());
e.printStackTrace();
return 5;
} //catch
PL/SQL Wrapper:
==========
CREATE OR REPLACE FUNCTION CODAROUL.SET_RMGOBJECT_NAAM(NAAM IN VARCHAR2) return NUMBER AS
LANGUAGE JAVA NAME 'RMG.BO.RMG_OBJECT.SET_RMGOBJECT_NAAM (java.lang.String) return java.lang.Integer';
Calling from SQL:
==========
CALL dbms_java.set_output(2000);
select CODAROUL.GET_RMGOBJECT_NAAM() from dual;
Edited by: RubenS_BE on Apr 6, 2012 5:35 AM
Edited by: 925945 on Apr 6, 2012 5:41 AM

Answer 1

You can do this by manually creating a new iterator binding in your binding tab.
So instead of dragging the VO directly to the page, go to the binding tab, add a new executable iterator binding, and point to that one from your ELs in the page itself.