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List:       ms-java-com
Subject:    Java COM development
From:       Jonathan Coogan <n9417018 () CC ! WWU ! EDU>
Date:       1998-11-26 5:08:52
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I have two questions about developing a COM/ActiveX object in Java.  I have written \
an ODL file that I wish to use.  I am using VJ++ 1.1 and version 2.01 of the SDK.

My first question is this:  After using MIDL or MKTYPLIB to create my type library, I \
use JAVATLB to generate the interfaces that my Java program needs to implement.  For \
"[propput]" properties, the resultant interface contains names that begin with "put" \
(such as "putName").  When I load the final control up in VB I can get property \
values, but I cannot set them.  I get a dialog box saying, "Object does not support \
this method or property."  The weird thing is that when I define the same property \
with a name that begins with "set" it works ("setName").  Is this some bug in the \
JAVATLB utility?  Should the generated Java interfaces really contain property names \
that begin with "set" and "get" instead of "put" and "get"?



Now for my second question:  I am not getting events from my Java control in VB.  I \
have noticed in the SDK samples that when you allow JAVAREG to create a type library \
for you, the event wiring is somehow handled magically, and events work perfectly in \
VB.  I am using JAVAREG in the following manner:

javareg.exe /register /control /codebase:**** /class:**** /clsid:{****} \
/typelib:****.tlb /nomktyplib

I suspect that my problems are due to the fact that I am using a preexisting type \
library instead of letting JAVAREG create one for me.  It is very important for me to \
do so because of the nature of my ODL file.  I cannot achieve the same behavior when \
I use the automatically generated type library.  Anyway, I'm hoping that someone can \
tell me how to "add VB as a listener" to my Java control.  I will include a simple \
example of what I have been trying to do.

/*
 *  BEGIN SAMPLE ODL (SampleBean.odl)
 */
[
  uuid(11372020-815E-11D2-9069-00A024D7933E),
  version(1.0),
  helpstring("SampleBean")
]
library SampleBean
{
    importlib("StdOle2.tlb");

    [
          uuid(11372022-815E-11D2-9069-00A024D7933E),
   dual
    ]
    interface ISampleBean : IDispatch
    {
            [id(1), propget]
            HRESULT textToDraw([out,retval] BSTR *textToDraw);
            [id(1), propput]
            HRESULT textToDraw([in] BSTR textToDraw);
    };

    [
      uuid(11372023-815E-11D2-9069-00A024D7933E)
    ]
    dispinterface ISampleBeanEvents {
        properties:
        methods:
            [id(2)]
            void somethingHappened();
    };

    [
      uuid(11372024-815E-11D2-9069-00A024D7933E)
    ]
    coclass SampleBean {
        [default] interface ISampleBean;
        [default, source] dispinterface ISampleBeanEvents;
    };
};
/*
 *  END SAMPLE ODL (SampleBean.odl)
 */

At this point I use MKTYPLIB to create the SampleBean.tlb file.  There are no errors. \
I then use the JAVATLB utility to generate the interfaces that I must implement.  I \
allow the interfaces to be created in c:\windows\java\trustlib.  The resultant \
summary file tells me that the interfaces have the following format:

public class samplebean/SampleBean extends java.lang.Object
{
}
public interface samplebean/ISampleBeanEvents extends com.ms.com.IUnknown
{
    public abstract void somethingHappened();
}
public interface samplebean/ISampleBean extends com.ms.com.IUnknown
{
    public abstract java.lang.String gettextToDraw();
    public abstract void puttextToDraw(java.lang.String);
}

Now I build my SampleBean.java file in which I have implemented the ISampleBean \
interface. The java file looks like this:

/*
 *  BEGIN SAMPLE JAVA FILE (SampleBean.java)
 */
import java.awt.*;
import java.awt.event.*;
import java.util.Vector;
import java.util.Date;

import com.ms.com.*;
import samplebean.*;

class SampleBean
extends      Panel
implements   ISampleBean
{
    public SampleBean()
    {
        enableEvents(AWTEvent.MOUSE_EVENT_MASK);
    }

    public void paint(Graphics g) {
        g.drawString(textToDraw, 20, 20);
    }

    interface ISampleBeanListener
    extends ISampleBeanEvents, java.util.EventListener
    {
    }

    transient Vector listeners = new Vector();

    public void addSampleBeanListener(ISampleBeanListener l) {

  synchronized( listeners )
  {
         if(listeners == null)
          listeners = new Vector();

      listeners.addElement(l);
  }
    }

    public void removeSampleBeanListener(ISampleBeanListener l)
    {
 synchronized( listeners )
 {
     listeners.removeElement(l);
        }
    }

    protected void processMouseEvent(MouseEvent e)
    {
        if((e.getID()) == MouseEvent.MOUSE_PRESSED)
fire_event:
        {
            synchronized( listeners )
            {
                if(listeners == null)
                    break fire_event;

                ISampleBeanListener snapshot[];

                snapshot = new ISampleBeanListener[listeners.size()];
                listeners.copyInto(snapshot);

                for (int i = 0; i < snapshot.length; i++)
                    snapshot[i].somethingHappened();

            }

        }

         super.processMouseEvent(e);
    }

    String textToDraw = "Some text...";

    public String gettextToDraw() {
        return textToDraw;
    }

    public void settextToDraw(String textToDraw)
    {
        // Notice this is what my first question was about.
        // Weird.

        puttextToDraw( textToDraw );
    }
    public void puttextToDraw(String textToDraw)
    {
        this.textToDraw = textToDraw;
        repaint();
    }
}
/*
 *  END SAMPLE JAVA FILE (SampleBean.java)
 */

Now all I have to do is register the class.  I do this with the following
command:

javareg.exe /register /control /class:SampleBean /codebase:. \
/clsid:{11372024-815E-11D2-9069-00A024D7933E} /nomktyplib /typelib:SampleBean.tlb

Now when I try to work with the control in VB, the events do not work.  Can someone \
please help me out?  Keep in mind that it is very important to me to use the type \
library from my ODL file (even if there's no reason to in this simple example).

Thankyou.

-Jon Coogan
 n9417018@cc.wwu.edu

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