I know how to bind a property, but how can I bind the call of a fuction?
For example: I have a ObjectProperty which points to a file. Now, I want to bind the path to its folder? If the value of ObjectProperty is C:\\user\Desktop\text.txt, the bonding should point to C:\\user\Desktop.
I thought I can call getParentFile() within the binding.
There a many ways to map an ObjectProperty, take a look at the class Bindings.
(All examples assume that you have a ObjectProperty<File> file)
Bindings.createObjectBinding(Callable<T> func, Observable... dependencies)
ObjectBinding<File> parent = Bindings.createObjectBinding(() -> {
File f = file.getValue();
return f == null ? null : f.getParentFile();
}, file);
Bindings.select(ObservableValue<?> root, String... steps)
ObjectBinding<File> parent = Bindings.select(file, "parentFile");
This will print a warning on the error-stream when file is null.
You can also create your own mapping method (which is similar to createObjectBinding):
public static <T,R> ObjectBinding<R> map(ObjectProperty<T> property, Function<T,R> function) {
return new ObjectBinding<R>() {
{
bind(property);
}
#Override
protected R computeValue() {
return function.apply(property.getValue());
}
#Override
public void dispose() {
unbind(property);
}
};
}
And use it
ObjectBinding<File> parent = map(file, f -> f == null ? null : f.getParentFile());
Related
I have a TableView that holds a Model class, which has a BooleanProperty as follow
#FXML
TableView<Model> tableView;
Model Class :
class Model{
BooleanProperty valid;
public Model()
{
valid = new SimpleBooleanProperty();
}
... getters and setters
}
What i want to acheive is to bind a button disable property with selected item valid Property in the Model class fom the tableView, i know that i can acheive that with listeners, but using a listener needs to set first the initial value properly, since they are not getting fired until there is some change, as an exemple in this case, if there is no selected item from the table and the button is set to be not disable from the start, it will still be like that, until the listener fired, this is why i prefer to use Bindings, since it doesn't care about the initial value. is there any way to do so with Bindings also ?
what i tried :
i tried this :
transferButton.disableProperty().bind(Bindings.when(tableView.getSelectionModel().selectedItemProperty().isNotNull()).then(
tableView.getSelectionModel().getSelectedItem().valideProperty()
).otherwise(false));
but the problem is that i'm getting the following error :
return value of "javafx.scene.control.TableView$TableViewSelectionModel.getSelectedItem()" is null
Even tho i put a condition to the binding : Bindings.when(tableView.getSelectionModel().selectedItemProperty().isNotNull()
You can use a custom binding which implements a listener: for example:
transferButton.disableProperty().bind(new BooleanBinding() {
{
tableView.getSelectionModel().selectedItemProperty().addListener(obs, oldSelection, newSelection) -> {
if (oldSelection != null) unbind(oldSelection.validProperty());
if (newSelection != null) bind(newSelection.validProperty());
invalidate();
});
bind(tableView.getSelectionModel().selectedItemProperty());
}
#Override
protected boolean computeValue() {
Model selection = tableView.getSelectionModel().getSelectedItem();
if (selection == null) return true ;
return ! selection.isValid();
}
});
There is also a selection API in the Bindings API which will work, though it is not robust and will generate spurious warnings when the selection is null:
transferButton.disableProperty().bind(Bindings.selectBoolean(
tableView.getSelectionModel().selectedItemProperty(),
"valid"
)).not());
Here's an approach of a custom select binding which uses functions to provide nested properties (similar to core SelectBinding, just replacing the reflective access to the nested properties by functions providing them)
The basic idea
start with binding to the root
keep the binding chain in the dependencies
update the binding chain on validating (no need to do anything as long as the binding is not valid)
implement state cleanup
Code example (here with a single function only, can be extended for a longer chain, though, by adding more functions and walk the providers)
/**
* Custom binding to a nested property using a Function to provide the nested.
*/
public class XSelectBinding<R, T> extends ObjectBinding<T> {
private ObservableList<ObservableValue<?>> dependencies;
private Function<R, ObservableValue<T>> provider;
public XSelectBinding(ObservableValue<R> root, Function<R, ObservableValue<T>> provider) {
if (root == null) {
throw new NullPointerException("root must not be null");
}
if (provider == null) {
throw new NullPointerException("provider must not be null");
}
dependencies = FXCollections.observableArrayList(root);
this.provider = provider;
bind(root);
}
/**
* Implemented to update dependencies and return the value of the nested property if
* available
*/
#Override
protected T computeValue() {
onValidating();
ObservableValue<?> child = dependencies.size() > 1 ? dependencies.get(1) : null;
return child != null ? (T) child.getValue() : null;
}
/**
* Updates dependencies and bindings on validating.
*/
protected void onValidating() {
// grab the root
ObservableValue<R> root = (ObservableValue<R>) dependencies.get(0);
// cleanup bindings and dependencies
unbindAll();
// rebind starting from root
dependencies.add(root);
ObservableValue<T> nestedProperty = root.getValue() != null ?
provider.apply(root.getValue()) : null;
if (nestedProperty != null) {
dependencies.add(nestedProperty);
}
bind(dependencies.toArray(new ObservableValue<?>[dependencies.size()]));
}
/**
* Unbinds and clears dependencies.
*/
private void unbindAll() {
unbind(dependencies.toArray(new ObservableValue<?>[dependencies.size()]));
dependencies.clear();
}
#Override
public ObservableList<?> getDependencies() {
return FXCollections.unmodifiableObservableList(dependencies);
}
/**
* Implemented to unbind all dependencies and clear references to path providers.
*/
#Override
public void dispose() {
unbindAll();
provider = null;
}
}
To use in the OP's context:
// XSelectBinding
ObjectBinding<Boolean> xSelectBinding = new XSelectBinding<Model, Boolean>(
table.getSelectionModel().selectedItemProperty(),
item -> item.validProperty());
transferButton.disableProperty().bind(BooleanExpression.booleanExpression(xSelectBinding).not());
I use Prism6 + Unity container for desktop application developing.
This is a long-read, sorry. So I ask at top: Prism SetProperty() function is not rising property changed event if input value is Unity singleton. And I understand why: because input value and save value have same reference to singleton instance. RaisePropertyChanged() don't help in this situation.
Long-read is statring...
So, I have a dependency property in my UserControl component:
public static readonly DependencyProperty WorksheetDataProperty =
DependencyProperty.Register("WorksheetData", typeof(WorksheetDataModel), typeof(SheetUserControl),
new PropertyMetadata(new WorksheetDataModel(), WorksheetDataPropertyChanged));
public WorksheetDataModel WorksheetData {
get { return (WorksheetDataModel)GetValue(WorksheetDataProperty); }
set { SetValue(WorksheetDataProperty, value); }
}
private void WorksheetDataPropertyChanged(WorksheetDataModel worksheetData) {
if (worksheetData == null)
return;
SheetGrid.Model.ActiveGridView.BeginInit();
this.ClearWorksheetModel();
this.ResizeWorksheetModel();
SheetGrid.Model.ActiveGridView.EndInit();
}
private static void WorksheetDataPropertyChanged(
DependencyObject d, DependencyPropertyChangedEventArgs e) {
((SheetUserControl)d).WorksheetDataPropertyChanged((WorksheetDataModel)e.NewValue);
}
It's important for me to invoke actions from WorksheetDataPropertyChanged() function.
And scheme without shared service (singleton) is working well: this function is called.
But now I want to share data between several modules. How I see it: I have some "parent" module, which load\save data from storage and shared this data with several other modules, which can modificate shared data, but can't save it.
And EventAggregator is not convenient for me: I don't want to create copies of data and then collect it again after modifications.
So I register my "shared service" as singleton:
_container.RegisterInstance(new WorksheetDataModel());
Now I can load data from database in "parent" viewmodel to singleton object created in previous step:
var data = _container.Resolve<WorksheetDataModel>();
data.Header = args.Header;
data.User = args.User;
data.RowHeader = new WorksheetRowHeader(_model.ReadRowHeader(data.Header.WshCode));
data.ColHeader = new WorksheetColHeader(_model.ReadColHeader(data.Header.WshCode));
data.Cells = _model.ReadCells(data.Header.WshCode);
Further, I notify child viewmodels about new data in singleton:
data.OnDataChanged?.Invoke();
And now most important code from child viewmodel.
In delegate handler I "apply" new value:
WorksheetData = _container.Resolve<WorksheetDataModel>();
WorksheetData is:
private WorksheetDataModel _worksheetData;
public WorksheetDataModel WorksheetData {
get { return _worksheetData; }
set { SetProperty(ref _worksheetData, value); }
}
And problem in this line:
set { SetProperty(ref _worksheetData, value); }
It works only once at first call, because _worksheetData is null. But then refernce of _worksheetData (pointer) setted to singleton and in all next call value and _worksheetData are identical for SetProperty() and, as result, it just quit.
I tried next code:
set {
SetProperty(ref _worksheetData, value);
RaisePropertyChanged("WorksheetData")
}
But no effect. WorksheetDataPropertyChanged() callback in UserControl component is not calling.
So, I don't know now how to better share some data between several modules.
Thanks for any advice.
WorksheetData does not change, the contents of the WorksheetDataModel instance change.
So to update your bindings,
either WorksheetDataModel implements INotifyPropertyChanged and/or uses INotifyCollectionChanged-implementing collections
or you let the view model listen to WorksheetDataModel.OnDataChanged and raise its own PropertyChanged to update all bindings to WorksheetData.
Example:
private WorksheetDataModel _worksheetData;
public WorksheetDataModel WorksheetData
{
get { return _worksheetData; }
set
{
if (_worksheetData != null)
_worksheetData.OnDataChanged -= DataChangedHandler;
SetProperty(ref _worksheetData, value);
if (_worksheetData != null)
_worksheetData.OnDataChanged += DataChangedHandler;
}
}
private void DataChangedHandler( object sender, DataChangedEventArgs args )
{
RaisePropertyChanged( nameof( WorksheetData ) );
}
I am trying to find a way to override a structuremap registry statement containing EnrichWith like so (here is the Registry class):
public class MyRegistry : Registry
{
public MyRegistry()
{
For(typeof(IMyList<int>)).EnrichWith(x => DecorateMyList(x)).Use(typeof(MyListA<int>));
For(typeof(IMyList<int>)).Use(typeof(MyListB<int>));
For<IMyList<string>>().Use<MyListA<string>>();
For<IMyList<string>>().Use<MyListB<string>>();
}
private object DecorateMyList(object o)
{
var genericParameters = o.GetType().GetGenericArguments();
var myListDecoratorType = typeof(MyListDecorator<>).MakeGenericType(genericParameters);
var decorated = Activator.CreateInstance(myListDecoratorType, new []{o});
return decorated;
}
}
public class MyRegistryUser
{
ObjectFactory.GetInstance<IMyList<string>>(); // Good: Returns an instance of MyListB<string> as expected
ObjectFactory.GetInstance<IMyList<int>>(); // Bad: Returns an instance of the decorator containing MyListB<int> - my second rule should have overridden the EnrichWith as well.
}
Am I right to think that there is a glitch in structure map or is there something I'm not seeing?
Thanks in advance
I have code like this:
//Fields
Product _prod, _existingProd;
void Test()
{
_prod = MakeAndPopulateSomeRandomProduct();
_existingProd = GetProdFromDb(1);
Mapper.CreateMap()
.AfterMap((s, d) =>
{
Console.WriteLine(d==_existingProd); //Why does this print false?
//Customize other properties on destination object
});
Mapper.Map(_prod, _existingProd);
}
When I call Test(), false is printed but I expected true. In my scenario, it is important to be able to access the original destination object via the AfterMap argument. I only included the fields to demonstrate the problem but in my real code, I don't have direct access to them. How can I access the object instances passed in to Map() when customizing the mapping?
The following example works. Probably you are using some type converter which creates new instance... Also please provide all mapping configurations to better understand the problem.
[TestFixture]
public class AfterMap_Test
{
//Fields
private Product _prod, _existingProd;
[Test]
public void Test()
{
Mapper.CreateMap<Product, Product>()
.AfterMap((s, d) =>
{
Trace.WriteLine(d == _existingProd); //Why does this print false?
//Customize other properties on destination object
});
_existingProd = new Product {P1 = "Destination"};
_prod = new Product {P1 = "Source"};
Mapper.Map(_prod, _existingProd);
}
}
internal class Product
{
public string P1 { get; set; }
}
Groovy offers some really neat language features for dealing with and implementing Java interfaces, but I seem kind of stuck.
I want to dynamically implement an Interface on a Groovy class and intercept all method calls on that interface using GroovyInterceptable.invokeMethod. Here what I tried so far:
public interface TestInterface
{
public void doBla();
public String hello(String world);
}
import groovy.lang.GroovyInterceptable;
class GormInterfaceDispatcher implements GroovyInterceptable
{
def invokeMethod(String name, args) {
System.out.println ("Beginning $name with $args")
def metaMethod = metaClass.getMetaMethod(name, args)
def result = null
if(!metaMethod)
{
// Do something cool here with the method call
}
else
result = metaMethod.invoke(this, args)
System.out.println ("Completed $name")
return result
}
TestInterface getFromClosure()
{
// This works, but how do I get the method name from here?
// I find that even more elegant than using invokeMethod
return { Object[] args -> System.out.println "An unknown method called with $args" }.asType(TestInterface.class)
}
TestInterface getThisAsInterface()
{
// I'm using asType because I won't know the interfaces
// This returns null
return this.asType(TestInterface.class)
}
public static void main(String[] args)
{
def gid = new GormInterfaceDispatcher()
TestInterface ti = gid.getFromClosure()
assert ti != null
ti.doBla() // Works
TestInterface ti2 = gid.getThisAsInterface()
assert ti2 != null // Assertion failed
ti2.doBla()
}
}
Returning the Closure works fine, but I couldn't figure a way to find out the name of the method being called there.
Trying to make a Proxy to the this reference itself (so that method calls will call invokeMethod) returns null.
You could use the Map coercion feature of Groovy to dynamically generate a Map that represents the given interface:
TestInterface getMapAsInterface() {
def map = [:]
TestInterface.class.methods.each() { method ->
map."$method.name" = { Object[] args->
println "Called method ${method.name} with ${args}"
}
}
return map.asType(TestInterface.class)
}
To complete the response of Christoph, as stated by this page, you can implement an interface with a closure. For example:
def map = [doBla: { println 'Bla!'}, hello: {world -> "Hello $world".toString()}] as TestInterface
map.hello 'Groovy' // returns 'Hello Groovy'