I'm porting our Wicket 1.4 app to Wicket 1.5. Visitors are now very different. What I would like to know is how do I handle a CONTINUAL_TRAVERSAL in Wicket 1.5? The existing 1.4 code is below:
public class MyFormVisitor implements IVisitor<Component, Object>, Serializable {
private static final long serialVersionUID = 7271477325583441433L;
private Set<Component> visited = new HashSet<Component>();
#Override
public Object component(Component c) {
if (!visited.contains(c)) {
visited.add(c);
c.add(new MandatoryBehavior());
c.add(new ErrorHighlightBehavior());
}
return IVisitor.CONTINUE_TRAVERSAL;
}
Just convert your method to something like this and you should be fine:
#Override
public void component(final Component c, final IVisit<Void> visit) {
if (!visited.contains(c)) {
visited.add(c);
c.add(new MandatoryBehavior());
c.add(new ErrorHighlightBehavior());
}
}
As you can see in the documentation you linked, the traversal is now controlled via the IVisit passed to the method. If none of the methods to either stop or not go deeper is called, the traversal will simply continue.
Related
This question is a follow up to this problem here: How to make retrofit API call using ViewModel and LiveData
The mistakes 1 and 2 highlighted in that post's response have been fixed. For mistake 3, I haven't yet moved the API call to a repository, but I will once the code start working properly.
So I'm trying to make an API call using Retrofit, using MVVM with LiveData and ViewModel. The API call (which currently is in the ViewModel), is working properly, but the changes is not being picked up by the Observer in the Activity.
I've setup my ViewModel observer as follow:
public class PopularGamesActivity extends AppCompatActivity {
private static final String igdbBaseUrl = "https://api-endpoint.igdb.com/";
private static final String FIELDS = "id,name,genres,cover,popularity";
private static final String ORDER = "popularity:desc";
private static final int LIMIT = 30;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_popular_games);
PopularGamesViewModel popViewModel = ViewModelProviders.of(this).get(PopularGamesViewModel.class);
popViewModel.getGameList().observe(this, new Observer<List<Game>>() {
#Override
public void onChanged(#Nullable List<Game> gameList) {
String firstName = gameList.get(0).getName();
Timber.d(firstName);
}
And my ViewModel code is as follow:
public class PopularGamesViewModel extends AndroidViewModel {
private static final String igdbBaseUrl = "https://api-endpoint.igdb.com/";
private static final String FIELDS = "id,name,genres,cover,popularity";
private static final String ORDER = "popularity:desc";
private static final int LIMIT = 30;
public PopularGamesViewModel(#NonNull Application application) {
super(application);
}
public LiveData<List<Game>> getGameList() {
final MutableLiveData<List<Game>> gameList = new MutableLiveData<>();
// Create the retrofit builder
Retrofit.Builder builder = new Retrofit.Builder()
.baseUrl(igdbBaseUrl)
.addConverterFactory(GsonConverterFactory.create());
// Build retrofit
Retrofit retrofit = builder.build();
// Create the retrofit client
RetrofitClient client = retrofit.create(RetrofitClient.class);
Call<List<Game>> call = client.getGame(FIELDS,
ORDER,
LIMIT);
call.enqueue(new Callback<List<Game>>() {
#Override
public void onResponse(Call<List<Game>> call, Response<List<Game>> response) {
Timber.d("api call sucesss");
if (response.body() != null) {
Timber.d("First game: " + response.body().get(0).getName());
gameList.setValue(response.body());
}
}
#Override
public void onFailure(Call<List<Game>> call, Throwable t) {
Timber.d("api call failed");
}
});
return gameList;
}
}
When I run the code, the onResponse in the ViewModel class will output the correct response from the API call, so the call is working properly. But the onChanged() in the PopularGamesActivity class will never get called. Can someone shed some light on what I'm doing wrong? Thank you!
Ok, so this turned out to be a weird android studio bug. I was initially running the code on my real nexus 4 device, and the onChange never gets called. However, after running it on an emulated device, it started working immediately. And now, it's working on my real device too.
I don't know the actual reason behind it, but if anyone in the future run into a problem where onChange won't get called, try switching device/emulators.
Cheers.
I debug the code on a device and have the same problem.
M'n solution was simply activate the device screen.
The screensaver was the problem..
In java-9 Skins made it into public scope, while Behaviors are left in the dark - nevertheless changed considerably, in now using InputMap for all input bindings.
CellBehaviorBase installs mouse bindings like:
InputMap.MouseMapping pressedMapping, releasedMapping;
addDefaultMapping(
pressedMapping = new InputMap.MouseMapping(MouseEvent.MOUSE_PRESSED, this::mousePressed),
releasedMapping = new InputMap.MouseMapping(MouseEvent.MOUSE_RELEASED, this::mouseReleased),
new InputMap.MouseMapping(MouseEvent.MOUSE_DRAGGED, this::mouseDragged)
);
A concrete XXSkin now installs the behavior privately:
final private BehaviorBase behavior;
public TableCellSkin(TableCell control) {
super(control);
behavior = new TableCellBehavior(control);
....
}
The requirement is replace the mousePressed behavior (in jdk9 context). The idea is to grab super's field reflectively, dispose all its mappings and install the custom behavior. For some reason that I don't understand, the old bindings are still active (though the old mappings are empty!) and are invoked before the new bindings.
Below is a runnable example to play with: the mapping to mousePressed is simply implemented to do nothing, particularly to not invoke super. To see the old bindings at work, I set a conditional debug breakpoint at CellBehaviorBase.mousePressed like (in Eclipse):
System.out.println("mousePressed super");
new RuntimeException("whoIsCalling: " + getNode().getClass()).printStackTrace();
return false;
Run a debug and click into any cell, then the output is:
mousePressed super
java.lang.RuntimeException: whoIsCalling: class de.swingempire.fx.scene.control.cell.TableCellBehaviorReplace$PlainCustomTableCell
at com.sun.javafx.scene.control.behavior.CellBehaviorBase.mousePressed(CellBehaviorBase.java:169)
at com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
//... lots more of event dispatching
// until finally the output in my custom cell behavior
Feb. 02, 2016 3:14:02 NACHM. de.swingempire.fx.scene.control.cell.TableCellBehaviorReplace$PlainCustomTableCellBehavior mousePressed
INFORMATION: short-circuit super: Bulgarisch
I would expect to only see the very last part, that is the printout by my custom behavior. It feels like I'm somehow fundamentally off - but can't nail it. Ideas?
The runnable code (sorry for its length, most is boiler-plate, though):
public class TableCellBehaviorReplace extends Application {
private final ObservableList<Locale> locales =
FXCollections.observableArrayList(Locale.getAvailableLocales());
private Parent getContent() {
TableView<Locale> table = createLocaleTable();
BorderPane content = new BorderPane(table);
return content;
}
private TableView<Locale> createLocaleTable() {
TableView<Locale> table = new TableView<>(locales);
TableColumn<Locale, String> name = new TableColumn<>("Name");
name.setCellValueFactory(new PropertyValueFactory<>("displayName"));
name.setCellFactory(p -> new PlainCustomTableCell<>());
TableColumn<Locale, String> lang = new TableColumn<>("Language");
lang.setCellValueFactory(new PropertyValueFactory<>("displayLanguage"));
lang.setCellFactory(p -> new PlainCustomTableCell<>());
table.getColumns().addAll(name, lang);
return table;
}
/**
* Custom skin that installs custom Behavior. Note: this is dirty!
* Access super's behavior, dispose to get rid off its handlers, install
* custom behavior.
*/
public static class PlainCustomTableCellSkin<S, T> extends TableCellSkin<S, T> {
private BehaviorBase<?> replacedBehavior;
public PlainCustomTableCellSkin(TableCell<S, T> control) {
super(control);
replaceBehavior();
}
private void replaceBehavior() {
BehaviorBase<?> old = (BehaviorBase<?>) invokeGetField(TableCellSkin.class, this, "behavior");
old.dispose();
// at this point, InputMap mappings are empty:
// System.out.println("old mappings: " + old.getInputMap().getMappings().size());
replacedBehavior = new PlainCustomTableCellBehavior<>(getSkinnable());
}
#Override
public void dispose() {
replacedBehavior.dispose();
super.dispose();
}
}
/**
* Custom behavior that's meant to override basic handlers. Here: short-circuit
* mousePressed.
*/
public static class PlainCustomTableCellBehavior<S, T> extends TableCellBehavior<S, T> {
public PlainCustomTableCellBehavior(TableCell<S, T> control) {
super(control);
}
#Override
public void mousePressed(MouseEvent e) {
if (true) {
LOG.info("short-circuit super: " + getNode().getItem());
return;
}
super.mousePressed(e);
}
}
/**
* C&P of default tableCell in TableColumn. Extended to install custom
* skin.
*/
public static class PlainCustomTableCell<S, T> extends TableCell<S, T> {
public PlainCustomTableCell() {
}
#Override protected void updateItem(T item, boolean empty) {
if (item == getItem()) return;
super.updateItem(item, empty);
if (item == null) {
super.setText(null);
super.setGraphic(null);
} else if (item instanceof Node) {
super.setText(null);
super.setGraphic((Node)item);
} else {
super.setText(item.toString());
super.setGraphic(null);
}
}
#Override
protected Skin<?> createDefaultSkin() {
return new PlainCustomTableCellSkin<>(this);
}
}
#Override
public void start(Stage primaryStage) throws Exception {
primaryStage.setScene(new Scene(getContent(), 400, 200));
primaryStage.setTitle(FXUtils.version());
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
/**
* Reflectively access super field.
*/
public static Object invokeGetField(Class source, Object target, String name) {
try {
Field field = source.getDeclaredField(name);
field.setAccessible(true);
return field.get(target);
} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
e.printStackTrace();
}
return null;
}
#SuppressWarnings("unused")
private static final Logger LOG = Logger
.getLogger(TableCellBehaviorReplace.class.getName());
}
Edit
The suggestion inherit from the abstract skin XXSkinBase instead of the concrete XXSkin (then you are free to install whatever behavior you want, dude :-) is very reasonable and should be the first option. In the particular case of XX being TableCell, that's currently not possible, as the base class contains abstract package-private methods. Also, there are XX that don't have an abstract base (like f.i. ListCell).
Might be a bug in InputMap:
Digging into the sources I found some internal book-keeping (eventTypeMappings) parallel to mappings (these are the handlers). InputMap is listening to changes in mappings and updates the internal book-keeping on changes
mappings.addListener((ListChangeListener<Mapping<?>>) c -> {
while (c.next()) {
// TODO handle mapping removal
if (c.wasRemoved()) {
for (Mapping<?> mapping : c.getRemoved()) {
removeMapping(mapping);
}
}
// removeMapping
private void removeMapping(Mapping<?> mapping) {
// TODO
}
Meaning that the internal structure is never cleaned, particularly not when the mappings are removed in behavior.dispose(). When looking up eventHandlers - by inputMap.handle(e), see debug stacktrace shown in the question - the old handler is found in the internal book-keeping structure.
Joys of early experiments ... ;-)
At the end, a (very dirty, very hacky!) solution is to take over InputMap's job and force a cleanup of the internals:
private void replaceBehavior() {
BehaviorBase<?> old = (BehaviorBase<?>) invokeGetField(TableCellSkin.class, this, "behavior");
old.dispose();
cleanupInputMap(old.getInputMap());
// at this point, InputMap mappings are empty:
// System.out.println("old mappings: " + old.getInputMap().getMappings().size());
replacedBehavior = new PlainCustomTableCellBehavior<>(getSkinnable());
}
/**
* This is a hack around InputMap not cleaning up internals on removing mappings.
* We remove MousePressed/MouseReleased/MouseDragged mappings from the internal map.
* Beware: obviously this is dirty!
*
* #param inputMap
*/
private void cleanupInputMap(InputMap<?> inputMap) {
Map eventTypeMappings = (Map) invokeGetField(InputMap.class, inputMap, "eventTypeMappings");
eventTypeMappings.remove(MouseEvent.MOUSE_PRESSED);
eventTypeMappings.remove(MouseEvent.MOUSE_RELEASED);
eventTypeMappings.remove(MouseEvent.MOUSE_DRAGGED);
}
BTW: just in case anybody is wondering wtf - without, my hack around the missing commitOnFocusLost when editing a cell stopped working in java-9.
Try in PlainCustomTableCellSkin to inherit from the abstract class TableCellSkinBase rather than from TableCellSkin.
Then you can call the super constructor, which takes an TableCellBehaviorBase object as additional param.
Then you can save your time replacing it, by initializing it directly with the right one.
Just for more claryfication:
TableCellSkin extends TableCellSkinBase
TableCellBehavior extends TableCellBehaviorBase
One more thing. You need to also call super.init(tableCell) in your constructor.
Take the TableCellSkin class as reference.
Is there any way to make a listener fire once and remove itself?
for(Spec spec : specs){
spec.myProperty().addListener((obs,ov,nv) -> {
if (nv.longValue() > 0){
//do whatever
spec.myProperty().removeListener(this);
}
});
}
That code won't work. I can only think of complicated solutions to this seemingly simple problem.
How about using an anonymous inner class instead of a lambda expression?
IntegerProperty property = new SimpleIntegerProperty();
InvalidationListener listener = new InvalidationListener() {
#Override
public void invalidated(Observable observable) {
//TODO do something
property.removeListener(this);
}
};
property.addListener(listener);
The answer was partly in the comments so I'll add my [brian] solution here.
public void someMethod(){
for(Spec spec : specs){
spec.myProperty().addListener(listener);
}
}
ChangeListener<Number> listener = new ChangeListener<Number>() {
public void changed(ObservableValue<? extends Number> obs, Number ov, Number nv) {
Spec spec = (Spec)((SimpleLongProperty)obs).getBean();
spec.myProperty().removeListener(this);
}
};
Note, when I create myProperty in the Spec class I use the full constructor to specify the bean. new SimpleLongProperty(this, "myProperty", 0l);
Even doing this you still can't use a lambda to remove this.
I'm trying to add a custom HeaderResponseContainer in my wicket application. The tutorial looks quite simple (see Positioning of contributions), but when I add these lines and run the application I alwas get an IllegalStateException:
java.lang.IllegalStateException: No FilteringHeaderResponse is present in the request cycle. This may mean that you have not decorated the header response with a FilteringHeaderResponse. Simply calling the FilteringHeaderResponse constructor sets itself on the request cycle
at org.apache.wicket.markup.head.filter.FilteringHeaderResponse.get(FilteringHeaderResponse.java:165)
at org.apache.wicket.markup.head.filter.HeaderResponseContainer.onComponentTagBody(HeaderResponseContainer.java:64)
at org.apache.wicket.markup.html.panel.DefaultMarkupSourcingStrategy.onComponentTagBody(DefaultMarkupSourcingStrategy.java:71)
...
Yes, I already saw the note about FilteringHeaderResponse. But I am not sure where I should call the constructor. I already tried to add it in renderHead before calling response.render but I still get the same exception:
public void renderHead(IHeaderResponse response) {
super.renderHead(response);
FilteringHeaderResponse resp = new FilteringHeaderResponse(response);
resp.render(new FilteredHeaderItem(..., "myKey"));
}
You can create a decorator that wraps responses in a FilteringHeaderResponse:
public final class FilteringHeaderResponseDecorator implements IHeaderResponseDecorator {
#Override
public IHeaderResponse decorate(IHeaderResponse response) {
return new FilteringHeaderResponse(response);
}
}
And that set it during application initialization:
Override
public void init() {
super.init();
setHeaderResponseDecorator(new FilteringHeaderResponseDecorator());
}
I just ran into this same problem and found that the Wicket In Action tutorial leaves out the part about setting up a custom IHeaderResponseDecorator in your main Wicket Application init. The Wicket guide has a more thorough example:
Apache Wicket User Guide - Put JavaScript inside page body
You need something like this in your wicket Application:
#Override
public void init()
{
setHeaderResponseDecorator(new JavaScriptToBucketResponseDecorator("myKey"));
}
/**
* Decorates an original IHeaderResponse and renders all javascript items
* (JavaScriptHeaderItem), to a specific container in the page.
*/
static class JavaScriptToBucketResponseDecorator implements IHeaderResponseDecorator
{
private String bucketName;
public JavaScriptToBucketResponseDecorator(String bucketName) {
this.bucketName = bucketName;
}
#Override
public IHeaderResponse decorate(IHeaderResponse response) {
return new JavaScriptFilteredIntoFooterHeaderResponse(response, bucketName);
}
}
I'm trying to create a page which is very similar to the Google Form creation page.
This is how I am attempting to model it using the GWT MVP framework (Places and Activities), and Editors.
CreateFormActivity (Activity and presenter)
CreateFormView (interface for view, with nested Presenter interface)
CreateFormViewImpl (implements CreateFormView and Editor< FormProxy >
CreateFormViewImpl has the following sub-editors:
TextBox title
TextBox description
QuestionListEditor questionList
QuestionListEditor implements IsEditor< ListEditor< QuestionProxy, QuestionEditor>>
QuestionEditor implements Editor < QuestionProxy>
QuestionEditor has the following sub-editors:
TextBox questionTitle
TextBox helpText
ValueListBox questionType
An optional subeditor for each question type below.
An editor for each question type:
TextQuestionEditor
ParagraphTextQuestionEditor
MultipleChoiceQuestionEditor
CheckboxesQuestionEditor
ListQuestionEditor
ScaleQuestionEditor
GridQuestionEditor
Specific Questions:
What is the correct way to add / remove questions from the form. (see follow up question)
How should I go about creating the Editor for each question type? I attempted to listen to the questionType value changes, I'm not sure what to do after. (answered by BobV)
Should each question-type-specific editor be wrapper with an optionalFieldEditor? Since only one of can be used at a time. (answered by BobV)
How to best manage creating/removing objects deep in the object hierarchy. Ex) Specifying answers for a question number 3 which is of type multiple choice question. (see follow up question)
Can OptionalFieldEditor editor be used to wrap a ListEditor? (answered by BobV)
Implementation based on Answer
The Question Editor
public class QuestionDataEditor extends Composite implements
CompositeEditor<QuestionDataProxy, QuestionDataProxy, Editor<QuestionDataProxy>>,
LeafValueEditor<QuestionDataProxy>, HasRequestContext<QuestionDataProxy> {
interface Binder extends UiBinder<Widget, QuestionDataEditor> {}
private CompositeEditor.EditorChain<QuestionDataProxy, Editor<QuestionDataProxy>> chain;
private QuestionBaseDataEditor subEditor = null;
private QuestionDataProxy currentValue = null;
#UiField
SimplePanel container;
#UiField(provided = true)
#Path("dataType")
ValueListBox<QuestionType> dataType = new ValueListBox<QuestionType>(new Renderer<QuestionType>() {
#Override
public String render(final QuestionType object) {
return object == null ? "" : object.toString();
}
#Override
public void render(final QuestionType object, final Appendable appendable) throws IOException {
if (object != null) {
appendable.append(object.toString());
}
}
});
private RequestContext ctx;
public QuestionDataEditor() {
initWidget(GWT.<Binder> create(Binder.class).createAndBindUi(this));
dataType.setValue(QuestionType.BooleanQuestionType, true);
dataType.setAcceptableValues(Arrays.asList(QuestionType.values()));
/*
* The type drop-down UI element is an implementation detail of the
* CompositeEditor. When a question type is selected, the editor will
* call EditorChain.attach() with an instance of a QuestionData subtype
* and the type-specific sub-Editor.
*/
dataType.addValueChangeHandler(new ValueChangeHandler<QuestionType>() {
#Override
public void onValueChange(final ValueChangeEvent<QuestionType> event) {
QuestionDataProxy value;
switch (event.getValue()) {
case MultiChoiceQuestionData:
value = ctx.create(QuestionMultiChoiceDataProxy.class);
setValue(value);
break;
case BooleanQuestionData:
default:
final QuestionNumberDataProxy value2 = ctx.create(BooleanQuestionDataProxy.class);
value2.setPrompt("this value doesn't show up");
setValue(value2);
break;
}
}
});
}
/*
* The only thing that calls createEditorForTraversal() is the PathCollector
* which is used by RequestFactoryEditorDriver.getPaths().
*
* My recommendation is to always return a trivial instance of your question
* type editor and know that you may have to amend the value returned by
* getPaths()
*/
#Override
public Editor<QuestionDataProxy> createEditorForTraversal() {
return new QuestionNumberDataEditor();
}
#Override
public void flush() {
//XXX this doesn't work, no data is returned
currentValue = chain.getValue(subEditor);
}
/**
* Returns an empty string because there is only ever one sub-editor used.
*/
#Override
public String getPathElement(final Editor<QuestionDataProxy> subEditor) {
return "";
}
#Override
public QuestionDataProxy getValue() {
return currentValue;
}
#Override
public void onPropertyChange(final String... paths) {
}
#Override
public void setDelegate(final EditorDelegate<QuestionDataProxy> delegate) {
}
#Override
public void setEditorChain(final EditorChain<QuestionDataProxy, Editor<QuestionDataProxy>> chain) {
this.chain = chain;
}
#Override
public void setRequestContext(final RequestContext ctx) {
this.ctx = ctx;
}
/*
* The implementation of CompositeEditor.setValue() just creates the
* type-specific sub-Editor and calls EditorChain.attach().
*/
#Override
public void setValue(final QuestionDataProxy value) {
// if (currentValue != null && value == null) {
chain.detach(subEditor);
// }
QuestionType type = null;
if (value instanceof QuestionMultiChoiceDataProxy) {
if (((QuestionMultiChoiceDataProxy) value).getCustomList() == null) {
((QuestionMultiChoiceDataProxy) value).setCustomList(new ArrayList<CustomListItemProxy>());
}
type = QuestionType.CustomList;
subEditor = new QuestionMultipleChoiceDataEditor();
} else {
type = QuestionType.BooleanQuestionType;
subEditor = new BooleanQuestionDataEditor();
}
subEditor.setRequestContext(ctx);
currentValue = value;
container.clear();
if (value != null) {
dataType.setValue(type, false);
container.add(subEditor);
chain.attach(value, subEditor);
}
}
}
Question Base Data Editor
public interface QuestionBaseDataEditor extends HasRequestContext<QuestionDataProxy>, IsWidget {
}
Example Subtype
public class BooleanQuestionDataEditor extends Composite implements QuestionBaseDataEditor {
interface Binder extends UiBinder<Widget, BooleanQuestionDataEditor> {}
#Path("prompt")
#UiField
TextBox prompt = new TextBox();
public QuestionNumberDataEditor() {
initWidget(GWT.<Binder> create(Binder.class).createAndBindUi(this));
}
#Override
public void setRequestContext(final RequestContext ctx) {
}
}
The only issue left is that QuestionData subtype specific data isn't being displayed, or flushed. I think it has to do with the Editor setup I'm using.
For example, The value for prompt in the BooleanQuestionDataEditor is neither set nor flushed, and is null in the rpc payload.
My guess is: Since the QuestionDataEditor implements LeafValueEditor, the driver will not visit the subeditor, even though it has been attached.
Big thanks to anyone who can help!!!
Fundamentally, you want a CompositeEditor to handle cases where objects are dynamically added or removed from the Editor hierarchy. The ListEditor and OptionalFieldEditor adaptors implement CompositeEditor.
If the information required for the different types of questions is fundamentally orthogonal, then multiple OptionalFieldEditor could be used with different fields, one for each question type. This will work when you have only a few question types, but won't really scale well in the future.
A different approach, that will scale better would be to use a custom implementation of a CompositeEditor + LeafValueEditor that handles a polymorphic QuestionData type hierarchy. The type drop-down UI element would become an implementation detail of the CompositeEditor. When a question type is selected, the editor will call EditorChain.attach() with an instance of a QuestionData subtype and the type-specific sub-Editor. The newly-created QuestionData instance should be retained to implement LeafValueEditor.getValue(). The implementation of CompositeEditor.setValue() just creates the type-specific sub-Editor and calls EditorChain.attach().
FWIW, OptionalFieldEditor can be used with ListEditor or any other editor type.
We implemented similar approach (see accepted answer) and it works for us like this.
Since driver is initially unaware of simple editor paths that might be used by sub-editors, every sub-editor has own driver:
public interface CreatesEditorDriver<T> {
RequestFactoryEditorDriver<T, ? extends Editor<T>> createDriver();
}
public interface RequestFactoryEditor<T> extends CreatesEditorDriver<T>, Editor<T> {
}
Then we use the following editor adapter that would allow any sub-editor that implements RequestFactoryEditor to be used. This is our workaround to support polimorphism in editors:
public static class DynamicEditor<T>
implements LeafValueEditor<T>, CompositeEditor<T, T, RequestFactoryEditor<T>>, HasRequestContext<T> {
private RequestFactoryEditorDriver<T, ? extends Editor<T>> subdriver;
private RequestFactoryEditor<T> subeditor;
private T value;
private EditorDelegate<T> delegate;
private RequestContext ctx;
public static <T> DynamicEditor<T> of(RequestFactoryEditor<T> subeditor) {
return new DynamicEditor<T>(subeditor);
}
protected DynamicEditor(RequestFactoryEditor<T> subeditor) {
this.subeditor = subeditor;
}
#Override
public void setValue(T value) {
this.value = value;
subdriver = null;
if (null != value) {
RequestFactoryEditorDriver<T, ? extends Editor<T>> newSubdriver = subeditor.createDriver();
if (null != ctx) {
newSubdriver.edit(value, ctx);
} else {
newSubdriver.display(value);
}
subdriver = newSubdriver;
}
}
#Override
public T getValue() {
return value;
}
#Override
public void flush() {
if (null != subdriver) {
subdriver.flush();
}
}
#Override
public void onPropertyChange(String... paths) {
}
#Override
public void setDelegate(EditorDelegate<T> delegate) {
this.delegate = delegate;
}
#Override
public RequestFactoryEditor<T> createEditorForTraversal() {
return subeditor;
}
#Override
public String getPathElement(RequestFactoryEditor<T> subEditor) {
return delegate.getPath();
}
#Override
public void setEditorChain(EditorChain<T, RequestFactoryEditor<T>> chain) {
}
#Override
public void setRequestContext(RequestContext ctx) {
this.ctx = ctx;
}
}
Our example sub-editor:
public static class VirtualProductEditor implements RequestFactoryEditor<ProductProxy> {
interface Driver extends RequestFactoryEditorDriver<ProductProxy, VirtualProductEditor> {}
private static final Driver driver = GWT.create(Driver.class);
public Driver createDriver() {
driver.initialize(this);
return driver;
}
...
}
Our usage example:
#Path("")
DynamicEditor<ProductProxy> productDetailsEditor;
...
public void setProductType(ProductType type){
if (ProductType.VIRTUAL==type){
productDetailsEditor = DynamicEditor.of(new VirtualProductEditor());
} else if (ProductType.PHYSICAL==type){
productDetailsEditor = DynamicEditor.of(new PhysicalProductEditor());
}
}
Would be great to hear your comments.
Regarding your question why subtype specific data isn't displayed or flushed:
My scenario is a little bit different but I made the following observation:
GWT editor databinding does not work as one would expect with abstract editors in the editor hierarchy. The subEditor declared in your QuestionDataEditor is of type QuestionBaseDataEditor and this is fully abstract type (an interface). When looking for fields/sub editors to populate with data/flush GWT takes all the fields declared in this type. Since QuestionBaseDataEditor has no sub editors declared nothing is displayed/flushed. From debugging I found out that is happens due to GWT using a generated EditorDelegate for that abstract type rather than the EditorDelegate for the concrete subtype present at that moment.
In my case all the concrete sub editors had the same types of leaf value editors (I had two different concrete editors one to display and one to edit the same bean type) so I could do something like this to work around this limitation:
interface MyAbstractEditor1 extends Editor<MyBean>
{
LeafValueEditor<String> description();
}
// or as an alternative
abstract class MyAbstractEditor2 implements Editor<MyBean>
{
#UiField protected LeafValueEditor<String> name;
}
class MyConcreteEditor extends MyAbstractEditor2 implements MyAbstractEditor1
{
#UiField TextBox description;
public LeafValueEditor<String> description()
{
return description;
}
// super.name is bound to a TextBox using UiBinder :)
}
Now GWT finds the subeditors in the abstract base class and in both cases I get the corresponding fields name and description populated and flushed.
Unfortunately this approach is not suitable when the concrete subeditors have different values in your bean structure to edit :(
I think this is a bug of the editors framework GWT code generation, that can only be solved by the GWT development team.
Isn't the fundamental problem that the binding happens at compile time so will only bind to QuestionDataProxy so won't have sub-type specific bindings? The CompositeEditor javadoc says "An interface that indicates that a given Editor is composed of an unknown number of sub-Editors all of the same type" so that rules this usage out?
At my current job I'm pushing to avoid polymorphism altogether as the RDBMS doesn't support it either. Sadly we do have some at the moment so I'm experimenting with a dummy wrapper class that exposes all the sub-types with specific getters so the compiler has something to work on. Not pretty though.
Have you seen this post: http://markmail.org/message/u2cff3mfbiboeejr this seems along the right lines.
I'm a bit worried about code bloat though.
Hope that makes some sort of sense!