// Begin writing the generated source.
ClassSourceFileComposerFactory f = new ClassSourceFileComposerFactory(
sourceType.getPackage().getName(), generatedSimpleSourceName);
f.addImport(GWT.class.getName());
f.addImport(PreferencesProvider.class.getName());
f.addImplementedInterface(typeName);
// All source gets written through this Writer
PrintWriter out = context.tryCreate(logger,
sourceType.getPackage().getName(), generatedSimpleSourceName);