Howto veto a selection Change in a JTree...

Hello,
i want to veto a SelectionChange in a javax.swing.JTree, and have found that such a thing is not supported by this Component.
What is the best way to implement a java.beans.VetoableChangeEvent Support on a SelectionChange in a javax.swing.JTree.
Has anybody done this thing, so that i do not have to reinvent the wheel again?
The princips of constrained Properties are clear for me, but
what Methods i have to overwrite in JTree?
Any suggestions are welcome.
with kind regards, carsten

Hi,
my approach is a little diffrent from yours. The left side of my App holds a Tree (single selection). The right side an Editor. If you select a Entry in Tree, the Data is loaded to the editor. If you change the selection to another Tree entry, the data in the Editor is validated, saved, and the Data of the new selected Entry is loaded. Now, if validation fails, the selectionChange should not take place (the Errors are marked by a Forms Framework), so that the user can correct them. I think, this is a requirement that very often occurs.
My approach to handle this requirement:
(I know that this does not work without adjustment. This first approach is only an idea). What do you think about that?
public class VetoableTreeSelectionModel extends DefaultTreeSelectionModel {
    private java.beans.VetoableChangeSupport vetoes = new VetoableChangeSupport(this);
    public VetoableTreeSelectionModel() { }
    public void addSelectionPaths(TreePath[] paths){
        if(!getVetoes()){
            super.addSelectionPaths(paths);
    public void addSelectionPath(TreePath path) {
        if(!getVetoes()){
            super.addSelectionPath(path);
    public void setSelectionPaths(TreePath[] paths){
        if(!getVetoes()){
            super.setSelectionPaths(paths);
    public void setSelectionPath(TreePath path) {
        if(!getVetoes()){
            super.setSelectionPath(path);
    private boolean getVetoes(){
        boolean result = false;
        try{
            vetoes.fireVetoableChange("Path", oldValue , newValue);
            System.out.println("### I have received NO vetoes.");
        }catch(java.beans.PropertyVetoException ex){
            System.out.println("### I have received a veto!");
            result=true;
        return result;
    public void addSeletionChangedVetoListener(VetoableChangeListener listener){
        vetoes.addVetoableChangeListener(listener);
    public void removeSeletionChangedVetoListener(VetoableChangeListener listener){
        vetoes.removeVetoableChangeListener(listener);
}carsten

Similar Messages

How to veto a JComboBox selection change in ItemListener

I have a JComboBox whose current value is tied to some data cached in my application. I want to be able to examine the selection in an ItemListener attached to the JComboBox, and if the value is different than what I have cached, I want to ask the user if they really want to change because the change will render some other data as no longer valid. If the user wants to abandon the change, then I want to "abandon" or "veto" the selection change and reset it to the old value.
For instance, if the combo box has values "Foo" and "Bar" in it, and "Foo" is the cached selection, then the user goes and changes the selection to "Bar", I want to prompt them with something like "You have changed the value to Bar. Doing so will render XXX no longer valid. Do you want to continue?" -- if they cancel the change, then leave the selection as "Foo".
What is the best way to do this within ItemListener's itemStateChanged? Are there better ways to do this besides what I've outlined? I didn't see anything in "Core JFC" book or the JDK documentation that discussed this sort of thing.
Thanks in advance,
Eric

Hi,
It is a design problem and not realy a language problem... The way I create vetoing design it that a keep the previous selection of the JComboBox... upon action I look if the application can do the new computation...if not...ask the user... if true| run calculations if not set the JComboBox to the previous selection...
JRG

How to generate selection change event through code in JTree?

I am developing an application which downloads the file from other system and adds it into the tree. On selecting any file in the tree I m displaying it's contents. But now i am trying to display the contents of downloaded file as soon as it's download completes. Here i am not getting the way to how to generate the event as the download completes, because i tried that setSelectionPath(TreePath path), but it also don't generates the selection change event. Is there any other way to do so?

Put null in place of oldLeadSelectionPath. From the API for TreeSelectionEvent:
protected TreePath oldLeadSelectionPath:
leadSelectionPath before the paths changed, may be null.
I'm at the office and can't try out anything, so please let me know whether that works for you.
db
edit Or it may be easier to put all code from your valueChanged (...) override in a new method and invoke that method both from valueChanged (...) and wherever else you need.
Edited by: Darryl.Burke

How to 'veto' a jList selection change

Hi All,
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The way I do it, is to implement a VetoableSelectionModel similar to a bean with a vetoable property: on selection change it queries registered VetoableChangeListeners if they don't object and backs out if one of them barks.
HTH
Jeanette

How to block lead selection change in a tree ?

Hi Guys,
Scenario
I have MasterTree - DetailEditor pair. MasterTree is used to visit some tree-structured data and DetailEditor is used to edit currently selected tree node.
Requirement
If currently selected node data is updated through DetailEditor and needs to be saved, than on a subsequent tree selection change the user should be warned about unsaved data.
Implementation
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Question
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Thanks in advance

Alex,
Here is a link to the phase model of WD:
http://help.sap.com/saphelp_nw04/helpdata/en/b8/cd96edb9c8794aa362e6e8b4236a1f/frameset.htm
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-Cindy

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I am developing Universal App. I have bind the images to the Gridview using ObservableCollection. I have set gridview
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Hi, Sorry for late reply,
Please change the class :
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private string source;
public string Source
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public int MyProperty { get; set; }
protected void SetProperty<T>(ref T storage, T value, [System.Runtime.CompilerServices.CallerMemberName] String propertyName = null)
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storage = value;
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PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
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if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
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XAML
<GridView x:Name="gd"
Tapped="gd_Tapped">
<GridView.ItemTemplate>
<DataTemplate>
<Grid Height="300" Width="250">
<Image Source="{Binding Source}" Stretch="Fill"/>
<Grid Height="100" Background="#B2000000" VerticalAlignment="Bottom">
<TextBlock Text="{Binding MyProperty}" FontSize="25" />
</Grid>
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
C#
//ObservableCollection of class
ObservableCollection<ImageCollection> img = new ObservableCollection<ImageCollection>();
public MainPage()
this.InitializeComponent();
img.Add(new ImageCollection() { MyProperty = 1, Source = "ms-appx:///Assets/Logo.scale-100.png" });
img.Add(new ImageCollection() { MyProperty = 2, Source = "ms-appx:///Assets/2.jpg" });
img.Add(new ImageCollection() { MyProperty = 3, Source = "ms-appx:///Assets/3.jpg" });
img.Add(new ImageCollection() { MyProperty = 4, Source = "ms-appx:///Assets/4.jpeg" });
gd.ItemsSource = img;
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GridView gv = (GridView)sender;
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ic.Source = "ms-appx:///Assets/4.jpeg";
gv.UpdateLayout();
I have used INotifyPropertyChanged now UI is not fluctuate
and I have not bind again O-Collection.
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shah

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Tab 0 was deleted.
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This trick is working, but you see, the problem is more
complicated. The problem is that stateChanged() doesn't work
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Both insertTab() and removeTabAt() (and maybe smth. else) causes this problem.
Maybe, possible solution will be to override some method of
JTabbedPane, responsible for activating a tab like this...?
tabbedPane = new JTabbedPane {
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at all??
In the deep sources of swing :) I've found such tricks:
In JTabbedPane.insertTab():accessibleContext.firePropertyChange(
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I've never worked with Accesibility :(
And I couldn't find out what to do having only swing sources.
Need help.

How can I set a property when an event happens? (selection changed on datagrid)

I have a datagrid, I would like to change the backgrund of the datagrid when the selection changed event is fired.
I can not use data trigger, because is in the case that I expected a value, but in this case is when change, to any value.
An option is to use an event trigger, but all the examples that I have found is to use with an actions, and I just want to set a property.
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I am using MVVM pattern, so I would like to avoid the use in code-behind.
Thank so much.

You could use an event trigger and implement your own TriggerAction<T> that sets the background property. There is an example of how to create a custom TriggerAction available here:
http://stackoverflow.com/questions/942548/setting-a-property-with-an-eventtrigger.
The following example sets the Background property of the DataGrid to a red SolidColorBrush when the SelectionChanged event is fired. It should give you the idea:
<DataGrid x:Name="dgrid"
xmlns:local="clr-namespace:WpfApplication22">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<local:SetPropertyAction PropertyName="Background" TargetObject="{Binding ElementName=dgrid}">
<local:SetPropertyAction.PropertyValue>
<SolidColorBrush>Red</SolidColorBrush>
</local:SetPropertyAction.PropertyValue>
</local:SetPropertyAction>
</i:EventTrigger>
</i:Interaction.Triggers>
<DataGrid.Columns>
namespace WpfApplication22
public class SetPropertyAction : TriggerAction<FrameworkElement>
public string PropertyName
get { return (string)GetValue(PropertyNameProperty); }
set { SetValue(PropertyNameProperty, value); }
public static readonly DependencyProperty PropertyNameProperty
= DependencyProperty.Register("PropertyName", typeof(string),
typeof(SetPropertyAction));
public object PropertyValue
get { return GetValue(PropertyValueProperty); }
set { SetValue(PropertyValueProperty, value); }
public static readonly DependencyProperty PropertyValueProperty
= DependencyProperty.Register("PropertyValue", typeof(object),
typeof(SetPropertyAction));
public object TargetObject
get { return GetValue(TargetObjectProperty); }
set { SetValue(TargetObjectProperty, value); }
public static readonly DependencyProperty TargetObjectProperty
= DependencyProperty.Register("TargetObject", typeof(object),
typeof(SetPropertyAction));
protected override void Invoke(object parameter)
object target = TargetObject ?? AssociatedObject;
PropertyInfo propertyInfo = target.GetType().GetProperty(
PropertyName,
BindingFlags.Instance|BindingFlags.Public
|BindingFlags.NonPublic|BindingFlags.InvokeMethod);
propertyInfo.SetValue(target, PropertyValue);
For more information about how to hook up event triggers and handle events in MVVM, please refer to my blog post:
http://blog.magnusmontin.net/2013/06/30/handling-events-in-an-mvvm-wpf-application/
Please also remember to mark helpful posts as answer.

Detail Table Not Changing When Master Table Selection Changes

Using JDev 11.1.1.6.
I am working through some Oracle tutorials (Storefront Demos).
I am accessing the Fusion Order Demo (FOD) schema.
I have created VOs based on BCs for Categories, Subcategories and Products.
I have added all to my data model and tested functionality using the AppModule. This works as expected.
When I drag the Subcategories onto my jsf page as Master-Detail (Table-Table), the initial list is based on the first index of the BrowseCategory data control.
When I click on another row in the master table, the detail table refreshes but the same data appears.
I confirmed that the selection changes on the master table.
I added a button on the page and checked the BrowseCategoryIterator using some backing bean code and the iterator remains on the first record.
I checked the SelectionListener on the table and it is set correctly as   "#{bindings.BrowseCategory1.collectionModel.makecurrent}"
Does anyone have any idea why the detail table is not getting updated based on a relationship to the master table?
Thanks,
Raymond

Hi,
From what you are saying:
     1. it's working in application module tester
     2. you verified the current row of the iterator and you found that it is stuck on the first row
The problem is then that the selection in the table is not setting the current row in the iterator.
Try to add a custom selection listener where you just execute the "#{bindings.BrowseCategory1.collectionModel.makecurrent}" expression. this is just to make sure that the listener is being called.
Also, the problem might be that the current row is correctly set by the table selection, but later in the life cycle it is being reset. so maybe you can also overwite the methods that set the current row in your VOimpl (again by jsut calling the supper) to check if and when these methods are called.
Regards,
Elias.

ITunes video reloads itself when no selection changes have been made.

Various video content reloads itself on my devices (iPad Air 2, iPad 2, iPhone 5, and iPhone 4) even though no selection changes have been made (no additional video selected, or deleted) between syncs. This issue turns a sync operation that should take less than a minute into 30 minutes or more! Since this issue has manifested itself across multiple devices, the common factor being my MacBook Pro must be the bad link.
Updates of OS and iTunes have not been enough to repair whatever is wrong.... I hope someone has a simple correction. Apple Support at local store, on phone, and Apple Engineering have not been able to help.
I believe I might need to somehow remove iTunes at a minimum (maybe OS too) from my MacBook Pro and rebuild it with best hopes of this issue finally correcting itself. Does anyone know how to go about a clean removal installation of iTunes and/or OS? Any other suggestions?
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