D-Bus in Java problem

[Matthew Johnson]

On Wed Jul 10 14:57, Martin H wrote:
> Hi, I am trying to communicate with a C++ Qt D-Bus daemon with a java
> program to call a method, which returns a string. First I checked the
> actual availability of the method via D-Bus with the tool D-Feet. So I am
> able to call the method with this tool and I receive the result I expect.
> 
> The problem is, when I use dbus-java-2.7, I get the following error:
> 
> org.freedesktop.dbus.exceptions.DBusExecutionException:
> com.sun.proxy.$Proxy2.get_perf_data(org.freedesktop.dbus.UInt64,
> org.freedesktop.dbus.UInt64)
>     at org.freedesktop.dbus.AbstractConnection.callMethodAsync(Unknown
> Source)
>     at
> de.tuberlin.kbs.performancemonitor.DataThread.retrieveDataFromDBus(DataThread.java:123)
>     at de.tuberlin.kbs.performancemonitor.DataThread.run(DataThread.java:59)
>     at java.lang.Thread.run(Thread.java:722)
> 
> It is kind of obvious, that the "Unknown Source" might be the problem, but
> I am hopelessly lost trying to determine the reason for this. For creation
> of the connection and the interface I use the following:

Unknown Source here just says that it was compiled without debug symbols.

> UInt64 from = new UInt64(0);
> UInt64 to = new UInt64(0);
> dBusConnection = DBusConnection.getConnection(DBusConnection.SESSION);
> dBusInterface =
> dBusConnection.getPeerRemoteObject("de.tuberlin.kbs.performancemonitor",
> "/");
> if(dBusInterface.isRemote())
>     dBusConnection.callMethodAsync(dBusInterface,
> "get_perf_data",from,to);

> The object IS remote and the method call produces the mentioned error.

Out of interest, why are you using callMethodAsync rather than a synchronous
call? Have you defined the java class matching your Interface?

MyInterface mi = (MyInterface) dbusConnection.getPeerRemoteObject(....);
mi.get_perf_data(from, to) would be the normal way to call here.

I can't remember if callMethodAsync works without a defined interface available, so that could be the problem.

Was there any other error message in the Exception? I'd expect something else. Did you miss something in your paste?

Thanks,
Matt
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