"From: Bill Hibbard " wrote:
>
> > - The client application needs to get some data values (doubles) from
> > the server. When I run the server as part of the same JVM (using none of
> > the Remote stuff) I can use the DataReference getData method and cast
> > that to a FieldImpl and call its getValues method. Running remotely, I
> > can't seem to cast the results of the (remote)DataReference getData
> > method to something like RemoteFieldImpl so I can call a getValues
> > method. Do I need a RemoteFieldImpl on the server?
>
> If the argument to DataReference.setData(Data d) on the server
> is a FieldImpl, then you should be able to cast the return value
> of DataReference.getData() to FieldImpl. That is, moving data
> from the server to the client does not change its class to
> Remote*.
>
What you said reaffirms what I thought, but it's not working in
practice. Here's some sample code that shows the problem. I get the
problem on both Linux and NT.
Thanks,
Doug
-------------------------------------- Server code ----------------
import java.rmi.Naming;
import java.rmi.RemoteException;
import visad.*;
public class Server
{
public Server()
throws Exception
{
RealType xtype = new RealType("x",null,null);
RealType ytype = new RealType("y",null,null);
FunctionType ftype = new FunctionType(xtype,ytype);
Set set = new Integer1DSet(1);
FieldImpl field = new FlatField(ftype,set);
double[][] data = {{1.0}};
field.setSamples(data);
DataReferenceImpl ref = new DataReferenceImpl("ref");
ref.setData(field);
// create RemoteDataReferenceImpl's
RemoteDataReferenceImpl[] rem_data_refs;
rem_data_refs = new RemoteDataReferenceImpl[1];
rem_data_refs[0] = new RemoteDataReferenceImpl(ref);
RemoteServerImpl rem_srv = new RemoteServerImpl(rem_data_refs);
Naming.rebind("//:/RemoteServerTest", rem_srv);
System.out.println("RemoteServer bound in registry");
}
public static void main(String args[])
throws Exception
{
Server s = new Server();
}
}
-------------------------------------- Client code ----------------
import java.rmi.Naming;
import java.rmi.RemoteException;
import visad.*;
public class Client
{
public Client()
throws Exception
{
String domain = "//:/RemoteServerTest";
RemoteServer remote_obj = (RemoteServer) Naming.lookup(domain);
DataReference ref = remote_obj.getDataReference(0);
System.out.println(ref.getType().toString()); // works
FieldImpl field = (FieldImpl) ref.getData(); // ClassCastException
double[][] data = field.getValues();
System.out.println(""+data[0][0]);
}
public static void main(String args[])
throws Exception
{
Client c = new Client();
}
}
--------------------------------------- jdb output ---------------
Uncaught exception: java.lang.ClassCastException:
visad.RemoteFieldImpl_Stub
at Client.<init>(Client.java:17)
at Client.main(Client.java:27)
at sun.tools.agent.MainThread.runMain(Native Method)
at sun.tools.agent.MainThread.run(MainThread.java:49)
--
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| Doug Lindholm, Software Engineer | E-mail: lind@xxxxxxxx |
| Research Applications Program | Phone: 303-497-8374 |
| National Center for Atmospheric Research | |
| P.O. Box 3000 | There's no place |
| Boulder, Colorado 80307-3000 | like $HOME |
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