ClassCastException getting IDispatch handle

[Alvin]

Hello Vikram!

I am using your latest release of j-interop (2.06) running on Windows XP SP3. I can't find ComFactory anymore, so I used JIObjectFactory. But I get an exception when getting a handle to IDispatch. But this is similar to your code on http://www.j-interop.org/sampleusage.html:

JISession session = JISession.createSession("localhost", "username", "password");
JIComServer comServer = new JIComServer(JIClsid.valueOf("429FD8AA-3D35-4F09-9B0B-0732DE6E4EAE"), session);
IJIComObject comObject = comServer.createInstance();
IJIDispatch dispatch = (IJIDispatch)JIObjectFactory.narrowObject(comObject.queryInterface("0AE6649D-9DA8-479D-9AC1-20E8F7E0C883"));

The exception was:

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: org.jinterop.dcom.core.JIComObjectImpl cannot be cast to org.jinterop.dcom.impls.automation.IJIDispatch
    at com.checkpt.eas.device.Evolve.initialize(Evolve.java:34)
    at com.checkpt.eas.device.Evolve.<init>(Evolve.java:26)
    at com.checkpt.eas.simulator.EvolveTester.<init>(EvolveTester.java:53)
    at com.checkpt.eas.simulator.EvolveTester$5.run(EvolveTester.java:384)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

Hope you can help me. Thanks!

[Vikram Roopchand]

Hi,
    I need to see your code.

best regards,
Vikram

[Alvin]

Hi Vikram!

Thanks for your immediate reply. Here's my code:

public class Evolve {
   
    private JISession session;
    private JIComServer comServer;
    private IJIComObject comObject;
    private IJIDispatch dispatch;
       
    public Evolve() {
        initialize();
    }
   
    public void initialize() {
        try {
            session = JISession.createSession("localhost", "username", "password");
            comServer = new JIComServer(JIClsid.valueOf("429FD8AA-3D35-4F09-9B0B-0732DE6E4EAE"), session);
            comObject = comServer.createInstance().queryInterface("0AE6649D-9DA8-479D-9AC1-20E8F7E0C883");
            dispatch = (IJIDispatch)JIObjectFactory.narrowObject(
                    comObject.queryInterface("0AE6649D-9DA8-479D-9AC1-20E8F7E0C883"));
        } catch(UnknownHostException unknownHostException) {
            unknownHostException.printStackTrace();
        } catch(JIException jiException) {
            jiException.printStackTrace();
        }
    }
   
    public long Open(String techID, String portName, short timeout) {
        long ret = 0;
               
        Object[] results = null;
        try {
            results = dispatch.callMethodA("Open", new Object[]{
                    techID, portName, new Short(timeout), new JIVariant(0, true)});
        } catch (JIException e) {
            e.printStackTrace();
        }
       
        for (int i = 0; i < results.length; i++)
            System.out.println(results[i]);
       
        return ret;
    }
}

And this was based from the IDL snippets:

    // EmeraldObject Interface Object
    [
        object,
        uuid(0AE6649D-9DA8-479D-9AC1-20E8F7E0C883),
        dual,
        helpstring("IEmeraldInterface Interface"),
        pointer_default(unique)
    ]
    interface IEmeraldInterface : IDispatch
    {
        [id(1), helpstring("method Open")]                        HRESULT Open([in] BSTR TechID, [in] BSTR PortName, [in] SHORT TimeOut, [out, retval] LONG* rc);
...

[Vikram Roopchand]

Hi,
    You have not asked for a IDispatch interface but you are type casting it to IDispatch.

comObject = comServer.createInstance().queryInterface("0AE6649D-9DA8-479D-9AC1-20E8F7E0C883");

The interface returned here is not IDispatch. In the next line it will throw an exception.

best regards,
Vikram

[Alvin]

Ooops sorry, wrong code.. That's just an edited one. It should be the same as my first post:

comObject = comServer.createInstance();
dispatch = (IJIDispatch)JIObjectFactory.narrowObject(comObject.queryInterface("0AE6649D-9DA8-479D-9AC1-20E8F7E0C883"));

Is the second line above incorrect for requesting an IDispatch? What should be the code then? Where will I put the uuid of the interface object, if I will be doing what you did on the sample usage page:

//Get a handle to it's IDispatch
IJIDispatch dispatch = (IJIDispatch)JIObjectFactory.narrowObject((IJIComObject)excelObject.queryInterface(IJIDispatch.IID));

Thank you!

[Alvin]

Hello!

The snippets below still didn't work. I still get ClassCastException. By the way, was the ComFactory obsoleted?

public class Evolve {

private JISession session;
private JIComServer comServer;
private IJIComObject comObject;
private IJIDispatch dispatch;

public Evolve() {
initialize();
}

public void initialize() {
try {
session = JISession.createSession("localhost", "username", "password");
comServer = new JIComServer(JIClsid.valueOf("429FD8AA-3D35-4F09-9B0B-0732DE6E4EAE"), session);
comObject = comServer.createInstance();
dispatch = (IJIDispatch)JIObjectFactory.narrowObject(
comObject.queryInterface("0AE6649D-9DA8-479D-9AC1-20E8F7E0C883"));
} catch(UnknownHostException unknownHostException) {
unknownHostException.printStackTrace();
} catch(JIException jiException) {
jiException.printStackTrace();
}
}

public long Open(String techID, String portName, short timeout) {
long ret = 0;

Object[] results = null;
try {
results = dispatch.callMethodA("Open", new Object[]{
techID, portName, new Short(timeout), new JIVariant(0, true)});
} catch (JIException e) {
e.printStackTrace();
}

for (int i = 0; i < results.length; i++)
System.out.println(results[i]);

return ret;
}
}