[vbox-dev] Java XPCOM API Problem

Matthias Jahn matthias.jahn at stud.tu-darmstadt.de
Mon Jul 16 00:46:06 PDT 2012


Hello,

I changed the glue-java.xsl file in the sources and compiled VBox on my 
own. The resulting Java XPCOM binding fixed the problem for me.

I created a patch file of the changes so that you can include it into 
the official sources. The patch works with 4.1.18 and should also work 
with svn head.

The patch is licensed under the MIT license.

Regards,
Matthias

On 09.07.2012 10:19, Matthias Jahn wrote:
> Hello,
>
> I have a problem using the Java XPCOM API to import an ova file. The
> import itself is working, but I get an exception, if I try to read the
> description values.
>
> My code snippet:
>
> public static void importAppliance(String path, String name) {
>     IAppliance appliance = virtualBox.createAppliance();
>
>     IProgress progress = appliance.read(path);
>     progress.waitForCompletion(-1);
>
>     appliance.interpret();
>
>     readDescription(appliance);
>
>     progress = appliance.importMachines(new LinkedList<ImportOptions>());
>     progress.waitForCompletion(-1);
> }
> 	
> private static void readDescription(IAppliance appliance) {
>     IVirtualSystemDescription description =
> appliance.getVirtualSystemDescriptions().get(0); //list size == 1
> 		
>     Holder<List<VirtualSystemDescriptionType>> typesHolder = new
> Holder<List<VirtualSystemDescriptionType>>();
>     Holder<List<String>> refsHolder = new Holder<List<String>>();
>     Holder<List<String>> ovfValuesHolder = new Holder<List<String>>();
>     Holder<List<String>> vboxValuesHolder = new Holder<List<String>>();
>     Holder<List<String>> extraConfigValuesValuesHolder = new
> Holder<List<String>>();
> 	
>     // the problematic call
>     description.getDescription(typesHolder, refsHolder, ovfValuesHolder,
> vboxValuesHolder, extraConfigValuesValuesHolder);
>
>     System.out.println(typesHolder.value);
>     System.out.println(refsHolder.value);
>     System.out.println(ovfValuesHolder.value);
>     System.out.println(vboxValuesHolder.value);
>     System.out.println(extraConfigValuesValuesHolder.value);
> }
>
>
> The resulting stack trace:
>
> Exception in thread "main" java.lang.AssertionError:
> java.lang.NoSuchMethodException:
> org.virtualbox_4_1.VirtualSystemDescriptionType.<init>(int)
> 	at org.virtualbox_4_1.xpcom.Helper.wrapEnum(Helper.java:101)
> 	at
> org.virtualbox_4_1.IVirtualSystemDescription.getDescription(IVirtualSystemDescription.java:58)
> 	at
> vdi.node.management.VirtualMachine.readDescription(VirtualMachine.java:229)
> 	at
> vdi.node.management.VirtualMachine.importAppliance(VirtualMachine.java:213)
> 	at de.tud.cs.rbg.vdi.test.vbox.App.main(App.java:12)
> Caused by: java.lang.NoSuchMethodException:
> org.virtualbox_4_1.VirtualSystemDescriptionType.<init>(int)
> 	at java.lang.Class.getConstructor0(Class.java:2723)
> 	at java.lang.Class.getConstructor(Class.java:1674)
> 	at org.virtualbox_4_1.xpcom.Helper.wrapEnum(Helper.java:94)
> 	... 4 more
>
> To be clear, if I comment out the call to readDescription() the import
> works fine. And if I use the GUI to import the ova, I can view and edit
> the appliance settings.
>
> I could not find the direct java sources for the API binding, but I
> found the file src/VBox/Main/glue/glue-java.xsl in the current
> VirtualBox sources, which contains the Helper class. I think the problem
> is, that Helper.wrapEnum() tries to call a constructor on an enum type.
> But in java enums are singletons.
>
> There seems to be an static method fromValue(long) in all enum types of
> the API. One solution could be, to use this static method instead of the
> constructor.
>
> Regards,
> Matthias
>
>
> P.S.:
> my environment:
> - Ubuntu 12.04 64bit
> - VirtualBox 4.1.18
>
>
> _______________________________________________
> vbox-dev mailing list
> vbox-dev at virtualbox.org
> https://www.virtualbox.org/mailman/listinfo/vbox-dev
>



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