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Using Java proxies

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Jiggy

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Aug 22, 1998, 3:00:00 AM8/22/98
to
Hello-

I've been trying to develop a simple application using the new 6.5 Java
proxy generator. I successfully generated a Java proxy class for a PB
NVO. But to use this class in a Java app I am forced to declare all
variables as STATIC. The online help says-

Define global variables for JDPB_Connection and your generated object:
JDPB_Connection myConnection = null;
n_cst_gentest myGentest = null;

Global variables ?! AFAIK, you can't have any in Java, right? So I
declared them as members of my main class. But when I call methods in
the proxy, or even - 'new JDPB_Connection(...)' the compiler gives the
following error -

Can't make a static reference to nonstatic variable <varname> in class
myclient

So I am forced to declare all classes and variables related to
com.sybase.dpb.* and my proxies as static. What am I missing here? Also
is there any example app available that demostrates how to use the Java
proxies?

thanx
Jiggy
_________________________________________________________________________

eMail:jig...@usa.net
Web: http://www.geocities.com/SiliconValley/Horizon/3837/


Jim Egan

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Aug 23, 1998, 3:00:00 AM8/23/98
to
Since PB 6.5 (6.0.1) is no longer in beta you should move this discussion
to one of the main newsgroups on the Sybase/Powersoft News Server. I'm not
saying you CAN'T post here but you might get a better response on a more
normal group. Also, please don't crosspost.
--
Jim Egan [TeamPS]
Houston, TX


Ajit Sabnis

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Aug 24, 1998, 3:00:00 AM8/24/98
to

Jiggy wrote:

> Hello-
>
> I've been trying to develop a simple application using the new 6.5 Java
> proxy generator. I successfully generated a Java proxy class for a PB
> NVO. But to use this class in a Java app I am forced to declare all
> variables as STATIC. The online help says-
>
> Define global variables for JDPB_Connection and your generated object:
> JDPB_Connection myConnection = null;
> n_cst_gentest myGentest = null;
>
> Global variables ?! AFAIK, you can't have any in Java, right? So I
> declared them as members of my main class. But when I call methods in
> the proxy, or even - 'new JDPB_Connection(...)' the compiler gives the
> following error -
>
> Can't make a static reference to nonstatic variable <varname> in class
> myclient
>
> So I am forced to declare all classes and variables related to
> com.sybase.dpb.* and my proxies as static. What am I missing here? Also
> is there any example app available that demostrates how to use the Java
> proxies?
>

You should not decalre any variables as static. You can declare variables as
class variables or in the method itself depending on how you want to access
them.

Here is a very simple Java client implementation .

HTH.

======= begin javaclnt.java ================

import java.lang.*;
import java.io.*;
import com.sybase.dpb.*;
import uo_test;

class javaclnt {

public static void main(String args[]) throws IOException {
JDPB_Connection myConn = null; // connection object
uo_test myObj = null; // remote object

//
// Set the connection attributes
//
String ServIP;
int ServPort;
ServIP = new String("localhost");
ServPort = 9999;
System.out.println("");

//
// Make the connection
//
System.out.println("Making Connection to DPB Server");
try {
myConn = new JDPB_Connection(ServIP, ServPort);
System.out.println("Connection successfull");
} catch (Exception e) {
System.out.println("---------------------");
System.out.print("Exception in JDBC_Connection : ");
System.out.println(e + " : " + e.getMessage());
e.printStackTrace();
return;
} catch (Throwable t) {
System.out.println("---------------------");
System.out.print("Throwable error in JDBC_Connection : ");
System.out.println(t + " : " + t.getMessage());
t.printStackTrace();
return;
}

//
// Create remote object
//
System.out.println("Creating remote object");
myObj = new uo_test(myConn);
System.out.println("Remote object created");

//
// Call method (of_string that takes string by value and returns
string)
//
String s1 = new String("Test string");
String r1;
System.out.println("Calling method uf_test");
try {
r1 = myObj.of_string(s1);
System.out.println("Method returned : " + r1);
} catch (RemoteException e) {
System.out.println("---------------------");
System.out.print("RemoteException on method : ");
System.out.println(e + " : " + e.getMessage());
e.printStackTrace();
}
//
// Disconnect
//
System.out.println("Disconnecting from DPB Server");
myConn.disconnect();
System.out.println("Disconnect successfull");

//
// Exit program
//
return;
}

}

======= end javaclnt.java ================

> thanx
> Jiggy
> _________________________________________________________________________
>
> eMail:jig...@usa.net
> Web: http://www.geocities.com/SiliconValley/Horizon/3837/

--
========================================================================
Ajit Sabnis *** Architecture for the New Enterprise ***
Sybase Inc. *** PowerBuilder 6.0 ***
========================================================================

Jiggy

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Aug 24, 1998, 3:00:00 AM8/24/98
to
Yes, the example that you gave does complie successfully. But if I move the connection declaration from a local variable to class member, I get the error I was talking about -

javaclnt.java:20: Can't make a static reference to nonstatic variable myConn in class javaclnt.

myConn = new JDPB_Connection(ServIP, ServPort);

^
Here's the modification

class javaclnt {

    JDPB_Connection myConn = null; // connection object
    public static void main(String args[]) throws IOException {

       ....
       ....

Is this because I am trying to assign a value to a non-static member inside a static method?

Jiggy
_________________________________________________________________________
eMail:jig...@usa.net
Web: http://www.geocities.com/SiliconValley/Horizon/3837/
 

Ajit Sabnis

unread,
Aug 25, 1998, 3:00:00 AM8/25/98
to

Jiggy wrote:

 Yes, the example that you gave does complie successfully. But if I move the connection declaration from a local variable to class member, I get the error I was talking about -

javaclnt.java:20: Can't make a static reference to nonstatic variable myConn in class javaclnt.
myConn = new JDPB_Connection(ServIP, ServPort);
^
Here's the modification

class javaclnt {
    JDPB_Connection myConn = null; // connection object
    public static void main(String args[]) throws IOException {
       ....
       ....

Is this because I am trying to assign a value to a non-static member inside a static method?

Jiggy

Well if you want to make the connection object a class member, then you will have to create a new instance of the class (can't directly refer to class member without creating a instance). So you will have to declare a vraible of the class type and go from there. For example using the above definition :

class javaclnt {
    JDPB_Connection myConn = null;

    public static void main(String args[]) throws IOException {

        javaclnt myclass;

        try {
            myclass = new javaclnt();
            myclass.myConn = new JDPB_Connection("localhost", 9999);
        } catch ....

HTH

Jiggy

unread,
Aug 25, 1998, 3:00:00 AM8/25/98
to
Got It. Thanx a lot

Jiggy
_________________________________________________________________________

eMail:jig...@usa.net
Web: http://www.geocities.com/SiliconValley/Horizon/3837/

Ajit Sabnis wrote:

>> > Ajit Sabnis *** Architecture for the New Enterprise ***
>> > Sybase Inc. *** PowerBuilder 6.0 ***
>> > ====================================================
>> > ===================
>> >
>>
>
>

> --
> ==
> =====================================================================

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