Create an Addon which changes InputMany value everytime a directory is selected in another UIInput: Bar.java @Inject @WithAttributes(label = "Select Files" ) private UIInputMany<FileResource<?>> files; @Inject @WithAttributes(label = "Select dir" ) private UIInput<DirectoryResource> dir; UIOutput out; @Override public void initializeUI(UIBuilder uiBuilder) throws Exception { dir.addValueChangeListener( new ValueChangeListener() { @Override public void valueChanged(ValueChangeEvent event) { List<FileResource<?>> fileList = (List<FileResource<?>>) files.getValue(); DirectoryResource selectedDir = (DirectoryResource) event.getNewValue(); for (Resource<?> resource : selectedDir.listResources()) { FileResource<?> fileToAdd = resource.reify(FileResource.class); if (fileToAdd != null && fileToAdd.exists() && !fileList.contains(fileToAdd)){ fileList.add(fileToAdd); } } //files.setValue(fileList); for (FileResource<?> fileResource : ((List<FileResource<?>>) files.getValue())) { out.out().println(fileResource.getName()); } } }); uiBuilder.add(dir).add(files); }