public class NatureAddingEditorCallback extends AbstractDirtyStateAwareEditorCallback {
	
	@Inject
	private ToggleXtextNatureAction toggleNature;

	@Override
	public void afterCreatePartControl(XtextEditor editor) {
		super.afterCreatePartControl(editor);
		IResource resource = editor.getResource();
		if (resource!=null && resource.getName().contains(".calculation")){		
                        toggleNature.toggleNature(resource.getProject());
		}
	}
}

public class CalculationUiModule extends de.dlr.virsat.calculation.model.ui.AbstractCalculationUiModule {
	public CalculationUiModule(AbstractUIPlugin plugin) {
		super(plugin);
	}
	
	 public Class<? extends org.eclipse.xtext.ui.editor.IXtextEditorCallback> bindIXtextEditorCallback() {

		// return your version of the NatureAddingEditorCallback
		return NatureAddingEditorCallback.class;
		}
}