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Javafx Link/Bind Treeview Items to ObservableList

I'm trying to find an easy way of linking a TreeView of type Download to an ObservableList of the same type.
MainController.java
public class MainController {
private ObservableList<Download> downloads = FXCollections.observableArrayList();
#FXML private TreeView<Download> $TreeDownloads;
#FXML
public void initialize() {
$TreeDownloads.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
$TreeDownloads.setNodeOrientation(NodeOrientation.LEFT_TO_RIGHT);
$TreeDownloads.setShowRoot(false);
downloads.addListener(new ListChangeListener<Download>() {
#Override
public void onChanged(Change<? extends Download> c) {
if (c.wasAdded()) {
addDownloads(c.getAddedSubList());
}
if (c.wasRemoved()) {
//
}
}
});
downloads.add(new Download("3847"));
downloads.add(new Download("3567"));
downloads.add(new Download("2357"));
}
private void addDownloads(List<? extends Download> downloads) {
downloads.forEach(download -> {
TreeItem<Download> treeItem = new TreeItem<>(download);
$TreeDownloads.getRoot().getChildren().add(treeItem);
new Thread(download::start).start();
});
}
private void removeDownloads(List<? extends Download> downloads) {
// remove treeitems from the treeview that hold these downloads
}
}
Download.java
public class Download {
private DoubleProperty progress = new SimpleDoubleProperty(0D);
private StringProperty id = new SimpleStringProperty("");
public Download(String id) {
this.id.set(id);
}
public void start() {
while (progress.getValue() < 1) {
try {
Thread.sleep(1000);
progress.add(0.1);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
#Override
public String toString() {
return id.getValue();
}
}
How do i implement a remove by Object(Download) mechanism, and is there an easier way to bind observablelist's items to a treeview?

Still not entirely certain what the exact problem is, all pretty straightforward:
First off, your list change listener implementation is incorrect, it must advance the subChanges before accessing its state (you did run your posted code, or not ;)
downloads.addListener(new ListChangeListener<Download>() {
#Override
public void onChanged(Change<? extends Download> c) {
// this while was missing
while (c.next()) {
if (c.wasAdded()) {
addDownloads(c.getAddedSubList());
}
if (c.wasRemoved()) {
// accessing the list of removed elements is .. plain standard api
removeDownloads(c.getRemoved());
}
}
}
});
Now implement the removal of the corresponding treeItems:
private void removeDownloads(List<? extends Download> downloads) {
// remove treeitems from the treeview that hold these downloads
List<TreeItem<Download>> treeItemsToRemove = treeDownloads.getRoot().getChildren().stream()
.filter(treeItem -> downloads.contains(treeItem.getValue()))
.collect(Collectors.toList());
treeDownloads.getRoot().getChildren().removeAll(treeItemsToRemove);
}
Asides:
java naming conventions use lowercase letters for members: treeDownloads (not $TreeDownloads)
the "verifiable" in MCVE implies being runnable as-is: the poster should be the first to verify that ;) yours wasn't due to incorrect implementation of the listener
the "minimal" in MCVE means leaving out everything that's not needed: f.i. calling the threading code - which in your first snippet was particularly distracting because violating fx' threading rule is a rather common error

JavaFX custom dialog has references after removing froom scene

I have a custom dialog that is added to the scene and then removed again. Doing profiling with VisualVM, I noticed that even after a GC run the instance of this dialog is still retained.
I know that this means that there must be a reference to that object somewhere so I had a look at the references:
As seen in the image there are a lot of references from this$ which means inner classes, in this case they are bindings or ChangeListeners. The change listener can be replaced with WeakChangeListener. I'm not quite sure how I should handle the Bindings however.
Furthermore there are some references that do not make much sense at first glance:
bean of type SimpleStringProperty or SimpleObjectProperty
oldParent and value of type Node$1
So here are the concrete questions:
How to get around these strong references, so the object can actually be garbage collected? Would the use of lambda expressions instead of anonymous inner classes have any effect in this respect? How to figure out where the object is references by bean, oldParent and value.
EDIT1:
The bean references of type SimpleStringProperty are used in the super class and therefore should not cause an issue here, I guess. One SimpleObjectProperty bean reference comes from a utility method that provides an EventHandler. How would I resolve that, is there something similar for EventHandler as for ChangeListeners?
EDIT2:
I tried to come up with a simple application to reproduce the same thing. I could manage it and saw that I have basically the same fields listed in the heap dump, but then noticed that I have retained a reference to the component that is removed from the scene in my application. Once I let go of that reference it was cleaned up. The only noticeable difference is in my small example there is no reference in an Object array.
EDIT3:
I did some digging and found two places in the code that when commented out or not used, will not cause the object become eligible for garbage collection. The first one is this ChangeListener:
sailorState.numberOfSailorsProperty().addListener(new ChangeListener<Number>() {
#Override
public void changed(ObservableValue<? extends Number> observableValue,
Number oldValue, Number newValue) {
int inTavern = newValue.intValue()-sailorsAdditionalOnShip.get();
if (inTavern < 0) {
sailorsAdditionalOnShip.set(Math.max(sailorsAdditionalOnShip.get() + inTavern, 0));
inTavern = 0;
}
sailorsInTavern.set(inTavern);
}
});
The second one is a bit more complex. The component is a Dialog that has a close button. On pressing that one the dialog closes. This is the code of the button, I do not think that with this part is the problem, but for completeness sake:
public class OpenPatricianButton extends Control {
protected final StringProperty text;
protected final ReadOnlyObjectProperty<Font> currentFont;
protected final ObjectProperty<EventHandler<MouseEvent>> onAction;
public OpenPatricianButton(String text,
final Font font) {
super();
this.text = new SimpleStringProperty(this, "text", text);
this.currentFont = new ReadOnlyObjectPropertyBase<Font>() {
#Override
public Object getBean() {
return this;
}
#Override
public String getName() {
return "currentFont";
}
#Override
public Font get() {
return font;
}
};
this.onAction = new SimpleObjectProperty<EventHandler<MouseEvent>>(this, "onAction");
this.getStyleClass().add(this.getClass().getSimpleName());
}
#Override
public String getUserAgentStylesheet() {
URL cssURL = getClass().getResource("/ch/sahits/game/javafx/control/"+getClass().getSimpleName()+".css");
return cssURL.toExternalForm();
}
public StringProperty textProperty() {
return text;
}
public String getText() {
return text.get();
}
public void setText(String text) {
this.text.set(text);
}
public Font getFont() {
return currentFont.get();
}
public ObjectProperty<EventHandler<MouseEvent>> onActionProperty() {
return onAction;
}
public EventHandler<MouseEvent> getOnAction() {
return onAction.get();
}
public void setOnAction(EventHandler<MouseEvent> onAction) {
this.onAction.set(onAction);
}
}
public class OpenPatricianSmallWaxButton extends OpenPatricianButton {
public OpenPatricianSmallWaxButton(String text,
final Font font) {
super(text, font);
}
#Override
protected Skin<?> createDefaultSkin() {
return new OpenPatricianSmallWaxButtonSkin(this);
}
public OpenPatricianSmallWaxButton(String text) {
this(text, Font.getDefault());
}
}
public class OpenPatricianSmallWaxButtonSkin extends SkinBase<OpenPatricianSmallWaxButton> {
public OpenPatricianSmallWaxButtonSkin(final OpenPatricianSmallWaxButton button) {
super(button);
InputStream is = getClass().getResourceAsStream("sealingWaxFlattend.png");
Image img = new Image(is);
final ImageView imageView = new ImageView(img);
final Label label = new Label();
label.textProperty().bind(button.textProperty());
label.getStyleClass().add("OpenPatricianSmallWaxButtonLabeled");
label.setFont(button.getFont());
label.onMouseClickedProperty().bind(button.onActionProperty());
label.textProperty().bind(button.textProperty());
imageView.onMouseReleasedProperty().bind(button.onActionProperty());
StackPane stack = new StackPane();
stack.getChildren().addAll(imageView, label);
Group group = new Group(stack);
group.setManaged(false);
button.setPrefHeight(img.getHeight());
button.setPrefWidth(img.getWidth());
getChildren().add(group);
}
}
And here is the code fragment where the button is instantiated:
closeButton = new OpenPatricianSmallWaxButton("X", font);
closeButton.setLayoutX(WIDTH - CLOSE_BUTTON_WIDTH - CLOSE_BUTTON_PADDING);
closeButton.setLayoutY(CLOSE_BTN_Y_POS);
closeButton.setOnAction(new EventHandler<MouseEvent>() {
#Override
public void handle(MouseEvent event) {
executeOnCloseButtonClicked();
}
});
closeButton.getStyleClass().add("buttonLabel");
getContent().add(closeButton);
The call to remove the button is done through Guava AsyncEventBus. Therefore the code is a bit length. It starts in the Application thread and then gets posted to the event bus thread which then eventually has to call Platform.runLater:
protected void executeOnCloseButtonClicked() {
ViewChangeEvent event = new ViewChangeEvent(MainGameView.class, EViewChangeEvent.CLOSE_DIALOG);
clientEventBus.post(event);
}
public void handleViewChange(ViewChangeEvent event) {
if (event.getAddresse().equals(MainGameView.class)) {
if (event.getEventNotice() instanceof DialogTemplate) {
setNewDialog((DialogTemplate) event.getEventNotice());
} else {
sceneEventHandlerFactory.getSceneEventHandler().handleEvent(event.getEventNotice());
}
}
}
public void handleEvent(Object eventNotice) {
Preconditions.checkNotNull(dialogContoller, "Dialog controller must be initialized first");
if (eventNotice == EViewChangeEvent.CLOSE_DIALOG) {
dialogContoller.closeDialog();
}
....
public void closeDialog() {
if (Platform.isFxApplicationThread()) {
closeDialogUnwrapped();
} else {
Platform.runLater(() -> closeDialogUnwrapped());
}
}
private void closeDialogUnwrapped() {
if (dialog != null) {
new Exception("Close dialog").printStackTrace();
getChildren().remove(dialog);
dialog = null;
dialogScope.closeScope();
}
}
The really peculiar thing is that the dialog can be cleaned up by the GC (provided the first issue with the ChangeListener is commented out) when I call closeDialog from a timer. In other words this behaviour does only happen if I close the dialog with a mouse click.

How to run two methods in sequence with the same button in javafx?

I'm trying to fill a listview with the artist and title of songs using the open() method.
To achieve this I created the artist and title ArrayLists and merged them using the create() method.
The problem is, when I try to run create() inside open() nothing happens. However, if I assign the create() method to a different button and click it after using the filechooser everything works fine.
So, I would like to know if it is possible to run the create() method after the open() method using only one button via fxml or regular java code.
public class PLController implements Initializable {
#Override
public void initialize(URL location, ResourceBundle resources) {
list.setItems(visibleList);
}
List<File> filelist = new ArrayList<File>();
ArrayList<String> title = new ArrayList<String>();
ArrayList<String> artist = new ArrayList<String>();
ObservableList<String> visibleList = FXCollections.observableArrayList();
#FXML
ListView<String> list;
#FXML
Button impButton;
public void create(){
for(int i = 0; i < title.size(); i++){
visibleList.add(artist.get(i) +" - " +title.get(i));
Collections.sort(visibleList);
}
}
public void handleMetadata(String key, Object value){
if (key.equals("title")){
title.add(value.toString());
}
if (key.equals("artist")){
artist.add(value.toString());
}
}
public void open(){
FileChooser chooser = new FileChooser();
filelist = chooser.showOpenMultipleDialog(impButton.getScene().getWindow());
for(File f:filelist){
try {
Media media = new Media(f.toURI().toURL().toString());
media.getMetadata().addListener(new MapChangeListener<String, Object>(){
#Override
public void onChanged(Change<? extends String, ? extends Object> change) {
if(change.wasAdded()) {
handleMetadata(change.getKey(), change.getValueAdded());
}
}
});
} catch (MalformedURLException e) {
e.printStackTrace();
}
}create(); //Nothing happens
}

As others have pointed out, the Media object does not have its metadata initialized immediately. (It needs to read data from the URL and populate those metadata as it receives them.) That is why the metadata are exposed as an ObservableMap. When you reach the end of your open() method, it is highly unlikely that the metadata will have been initialized, so your create() method will not see any data at that point.
What you need to do is observe the map, and update the ListView once both the artist and title are available. The best way to do this, in my opinion, is to encapsulate the information you want into a separate class:
public class Video {
private final Media media ;
private final ReadOnlyStringWrapper artist = new ReadOnlyStringWrapper("Unknown");
private final ReadOnlyStringWrapper title = new ReadOnlyStringWrapper("Title");
public Video(File file) {
try {
this.media = new Media(file.toURI().toURL().toExternalForm());
artist.bind(Bindings.createStringBinding(() -> {
Object a = media.getMetadata().get("artist");
return a == null ? "Unknown" : a.toString();
}, media.getMetadata()));
title.bind(Bindings.createStringBinding(() -> {
Object t = media.getMetadata().get("title");
return t == null ? "Unknown" : t.toString();
}, media.getMetadata()));
}
catch (Exception e) {
throw new RuntimeException("Could not create Video for "+file, e);
}
}
public ReadOnlyStringProperty titleProperty() {
return title.getReadOnlyProperty();
}
public ReadOnlyStringProperty artistProperty() {
return artist.getReadOnlyProperty();
}
public final String getTitle() {
return title.get();
}
public final String getArtist() {
return artist.get();
}
public final Media getMedia() {
return media ;
}
}
Now you can create a ListView<Video> to display the videos. Use a cell factory to display the artist and the title in the format you want. You can make sure that the observable list fires updates when either the artist or title properties change, and you can keep it sorted via a SortedList.
#FXML
private ListView<Video> list ;
private ObservableList<Video> visibleList ;
public void initialize() {
visibleList = FXCollections.observableArrayList(
// make list fire updates when artist or title change:
v -> new Observable[] {v.artistProperty(), v.titleProperty()});
list.setItems(new SortedList<>(list, Comparator.comparing(this::formatVideo)));
list.setCellFactory(lv -> new ListCell<Video>() {
#Override
public void updateItem(Video item, boolean empty) {
super.updateItem(item, empty) ;
setText(formatVideo(item));
}
});
}
#FXML
private void open() {
FileChooser chooser = new FileChooser();
List<File> fileList = chooser.showOpenMultipleDialog(impButton.getScene().getWindow());
if (fileList != null) {
fileList.stream()
.map(Video::new)
.forEach(visibleList::add);
}
}
private String formatVideo(Video v) {
if (v == null) return "" ;
return String.format("%s - %s", v.getArtist(), v.getTitle());
}

Simply creating a Media object and assigning a listener to it won't fire the code in the listener. So the title list in your code remains empty. The create() method is called, but since you are iterating over an empty list, nothing actually happens.
Use a debugger or add some logging information in such cases.
Also, you should sort the list after the for loop, not every time you add an item.

Not able to sort CellTable Column

Trying to make my CellTable Colum sortable but I'm not getting it to work. I'm having an MVP application which gets data from a rest service. To show the data within the table works fine but to sort is doesn't work.
public class LicenseUsageUserViewImpl<T> extends Composite implements LicenseUsageUserView<T> {
#UiTemplate("LicenseUsageUserView.ui.xml")
interface LicenseDataViewUiBinder extends UiBinder<ScrollPanel,LicenseUsageUserViewImpl> {}
private static LicenseDataViewUiBinder uiBinder = GWT.create(LicenseDataViewUiBinder.class);
#UiField
CellTable<GWTLicenseUser> licenseUserCellTable;
List<GWTLicenseUser> licenseUsers;
ListDataProvider<GWTLicenseUser> dataProvider;
public List<GWTLicenseUser> getLicenseUsers() {
return licenseUsers;
}
public void setLicenseUsers(List<GWTLicenseUser> licenseUsers) {
this.licenseUsers = licenseUsers;
}
#UiField Label header;
ListHandler<GWTLicenseUser> sortHandler;
public LicenseUsageUserViewImpl() {
initWidget(uiBinder.createAndBindUi(this));
initCellTable();
}
#Override
public void setLicenseUsersTable(List<GWTLicenseUser> tmpLicenseUsers) {
if (tmpLicenseUsers.isEmpty()) {
licenseUserCellTable.setVisible(false);
} else {
setLicenseUsers(tmpLicenseUsers);
licenseUserCellTable.setWidth("100%");
licenseUserCellTable.setVisible(true);
licenseUserCellTable.setPageSize(getLicenseUsers().size());
licenseUserCellTable.setRowCount(getLicenseUsers().size(), false);
licenseUserCellTable.setRowData(0, getLicenseUsers());
licenseUserCellTable.setVisibleRange(new Range(0, licenseUserCellTable.getRowCount()));
sortHandler.setList(getLicenseUsers());
dataProvider.getList().clear();
dataProvider.getList().addAll(getLicenseUsers());
}
}
#Override
public void initCellTable() {
sortHandler = new ListHandler<GWTLicenseUser>(getLicenseUsers());
licenseUserCellTable.addColumnSortHandler(sortHandler);
licenseUserCellTable.setWidth("100%");
licenseUserCellTable.setVisible(true);
licenseUserCellTable.setVisibleRange(new Range(0, licenseUserCellTable.getRowCount()));
// Create a data provider.
dataProvider = new ListDataProvider<GWTLicenseUser>();
// Connect the table to the data provider.
dataProvider.addDataDisplay(licenseUserCellTable);
licenseUserCellTable.setWidth("100%");
licenseUserCellTable.setAutoHeaderRefreshDisabled(true);
licenseUserCellTable.setAutoFooterRefreshDisabled(true);
// userID
TextColumn<GWTLicenseUser> userIdColumn = new TextColumn<GWTLicenseUser>() {
#Override
public String getValue(GWTLicenseUser object) {
if (object != null ){
return object.getUserId();
} else {
return "NULL";
}
}
};
userIdColumn.setSortable(true);
sortHandler.setComparator(userIdColumn, new Comparator<GWTLicenseUser>() {
#Override
public int compare(GWTLicenseUser o1, GWTLicenseUser o2) {
return o1.getUserId().compareTo(o2.getUserId());
}
});
licenseUserCellTable.addColumn(userIdColumn, "User ID");
// more column entries
licenseUserCellTable.getColumnSortList().push(userIdColumn);
licenseUserCellTable.getColumnSortList().push(countColumn);
licenseUserCellTable.addColumnSortHandler(sortHandler);
}
}
setLicenseUsersTable is called from my activity with the response list of my users. When I start my application and make a rest call my data is provide and put into my list also shown within the CellTable but its not sortable, but I have this sort icon before my colum name. I figured I post the whole code because I think its know easier to see what I'm trying to do.
Thanks for any help.

Remove this line:
sortHandler.setList(getLicenseUsers());
You already passed a List into the SortHandler constructor in
sortHandler = new ListHandler<GWTLicenseUser>(getLicenseUsers());
Also, instead of
setLicenseUsers(tmpLicenseUsers);
you may need to use
licenseUsers.addAll(tmpLicenseUsers);
I hope one of them fixes the problem.

GWT Editors - how to add N sub-editors of the same type based on a Collection

I have an object, Supply, that can either be an ElecSupply or GasSupply (see related question).
Regardless of which subclass is being edited, they all have a list of BillingPeriods.
I now need to instantiate N number of BillingPeriodEditors based on the contents of that list, and am pretty baffled as to how I should do it.
I am using GWTP. Here is the code of the SupplyEditor I have just got working:
public class SupplyEditor extends Composite implements ValueAwareEditor<Supply>
{
private static SupplyEditorUiBinder uiBinder = GWT.create(SupplyEditorUiBinder.class);
interface SupplyEditorUiBinder extends UiBinder<Widget, SupplyEditor>
{
}
#Ignore
final ElecSupplyEditor elecSupplyEditor = new ElecSupplyEditor();
#Path("")
final AbstractSubTypeEditor<Supply, ElecSupply, ElecSupplyEditor> elecSupplyEditorWrapper = new AbstractSubTypeEditor<Supply, ElecSupply, ElecSupplyEditor>(
elecSupplyEditor)
{
#Override
public void setValue(final Supply value)
{
setValue(value, value instanceof ElecSupply);
if(!(value instanceof ElecSupply))
{
showGasFields();
}
else
{
showElecFields();
}
}
};
#Ignore
final GasSupplyEditor gasSupplyEditor = new GasSupplyEditor();
#Path("")
final AbstractSubTypeEditor<Supply, GasSupply, GasSupplyEditor> gasSupplyEditorWrapper = new AbstractSubTypeEditor<Supply, GasSupply, GasSupplyEditor>(
gasSupplyEditor)
{
#Override
public void setValue(final Supply value)
{
setValue(value, value instanceof GasSupply);
if(!(value instanceof GasSupply))
{
showElecFields();
}
else
{
showGasFields();
}
}
};
#UiField
Panel elecPanel, gasPanel, unitSection;
public SupplyEditor()
{
initWidget(uiBinder.createAndBindUi(this));
gasPanel.add(gasSupplyEditor);
elecPanel.add(elecSupplyEditor);
}
// functions to show and hide depending on which type...
#Override
public void setValue(Supply value)
{
if(value instanceof ElecSupply)
{
showElecFields();
}
else if(value instanceof GasSupply)
{
showGasFields();
}
else
{
showNeither();
}
}
}
Now, as the list of BillingPeriods is a part of any Supply, I presume the logic for this should be in the SupplyEditor.
I got some really good help on the thread How to access PresenterWidget fields when added dynamically, but that was before I had implemented the Editor Framework at all, so I think the logic is in the wrong places.
Any help greatly appreciated. I can post more code (Presenter and View) but I didn't want to make it too hard to read and all they do is get the Supply from the datastore and call edit() on the View.
I have had a look at some examples of ListEditor but I don't really get it!

You need a ListEditor
It depends of how you want to present them in your actual view, but the same idea apply:
public class BillingPeriodListEditor implements isEditor<ListEditor<BillingPeriod,BillingPeriodEditor>>, HasRequestContext{
private class BillingPeriodEditorSource extends EditorSource<BillingPeriodEditor>{
#Override
public EmailsItemEditor create(final int index) {
// called each time u add or retrive new object on the list
// of the #ManyToOne or #ManyToMany
}
#Override
public void dispose(EmailsItemEditor subEditor) {
// called each time you remove the object from the list
}
#Override
public void setIndex(EmailsItemEditor editor, int index) {
// i would suggest track the index of the subeditor.
}
}
private ListEditor<BillingPeriod, BillingPeriodEditor> listEditor = ListEditor.of(new BillingPeriodEditorSource ());
// on add new one ...
// apply or request factory
// you must implement the HasRequestContext to
// call the create.(Proxy.class)
public void createNewBillingPeriod(){
// create a new one then add to the list
listEditor.getList().add(...)
}
}
public class BillingPeriodEditor implements Editor<BillingPeriod>{
// edit you BillingPeriod object
}
Then in you actual editor edit as is in the path Example getBillingPeriods();
BillingPeriodListEditor billingPeriods = new BillingPeriodListEditor ();
// latter on the clickhandler
billingPeriods.createNewBillingPeriod()
You are done now.