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<TITLE>Throwing an Exception from a Remote Method
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<META CONTENT="Patrick Chan" NAME="AUTHOR">
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<h3>
e192.
Throwing an Exception from a Remote Method</h3>
1. Define the remote interface.
<pre>
import java.rmi.*;
public interface <font color="#0066ff"><i>RObject</i></font> extends Remote {
void <font color="#0066ff"><i>aMethod</i></font>() throws RemoteException;
}
</pre>
2. Define the remote object implementation.
<pre>
import java.rmi.*;
import java.rmi.server.UnicastRemoteObject;
public class <font color="#0066ff"><i>RObjectImpl</i></font> extends UnicastRemoteObject implements <font color="#0066ff"><i>RObject</i></font> {
public <font color="#0066ff"><i>RObjectImpl</i></font>() throws RemoteException {
super();
}
public void <font color="#0066ff"><i>aMethod</i></font>() throws RemoteException {
// The actual exception must be wrapped in a RemoteException
throw new RemoteException(<font color="#0066ff"><i>"message"</i></font>, new <font color="#0066ff"><i>FileNotFoundException</i></font>(<font color="#0066ff"><i>"message"</i></font>));
}
}
</pre>
3. Compile the remote object implementation.
<pre>
> javac <font color="#0066ff"><i>RObject</i></font>.java <font color="#0066ff"><i>RObjectImpl</i></font>.java
</pre>
4. Generate the skeletons and stubs.
<pre>
> rmic <font color="#0066ff"><i>RObjectImpl</i></font>
</pre>
5. Create an instance of the remote object and bind it to the RMI registry.
<pre>
try {
<font color="#0066ff"><i>RObject</i></font> robj = new <font color="#0066ff"><i>RObjectImpl</i></font>();
Naming.rebind("//localhost/<font color="#0066ff"><i>RObjectServer</i></font>", robj);
} catch (MalformedURLException e) {
} catch (UnknownHostException e) {
} catch (RemoteException e) {
}
</pre>
6. Look up the remote object, invoke the method, and catch the exception.
<pre>
try {
// Look up the remote object.
<font color="#0066ff"><i>RObject</i></font> robj = (<font color="#0066ff"><i>RObject</i></font>) Naming.lookup(<font color="#0066ff"><i>"//localhost/RObjectServer"</i></font>);
// Invoke the method.
robj.<font color="#0066ff"><i>aMethod</i></font>();
} catch (MalformedURLException e) {
} catch (UnknownHostException e) {
} catch (NotBoundException e) {
} catch (RemoteException e) {
// Get the actual exception that was thrown.
Throwable realException = e.detail;
}
</pre>
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Related Examples
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e187. <a class="eglink" href="StartRegistry.html?l=rel">
Starting the RMI Registry
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e188. <a class="eglink" href="DefineRemote.html?l=rel">
Defining and Exporting a Remote Object
</a>
<br>
e189. <a class="eglink" href="LookupRemote.html?l=rel">
Looking Up a Remote Object and Invoking a Method
</a>
<br>
e190. <a class="eglink" href="args_Args.html?l=rel">
Passing Parameters to a Remote Method
</a>
<br>
e191. <a class="eglink" href="return_Return.html?l=rel">
Returning Values from a Remote Method
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