Package com.vaadin.flow.component

Class SignalPropertySupport<T>

java.lang.Object

com.vaadin.flow.component.SignalPropertySupport<T>

Type Parameters:

T - the type of the property

All Implemented Interfaces:

Serializable

public class SignalPropertySupport<T>
extends Object
implements Serializable

Helper class for binding a Signal to a property of a Component. Not all component features delegate directly to the state in Element. For those features, this helper class ensures state management behaves consistently with Element properties.

Example of usage:

 ValueSignal<String> signal = new ValueSignal<>("");
 MyComponent component = new MyComponent();
 add(component);
 component.bindTextContent(signal);
 signal.set("Hello"); // component content showing now "Content: Hello" text
 

 @Tag(div)
 public class MyComponent extends Component {
     private final SignalPropertySupport<String> textProperty = SignalPropertySupport
             .create(this, value -> {
                 getElement().executeJs("this.textContent = 'Content: ' + $0",
                         value);
             });

     public String getText() {
         return textProperty.get();
     }

     public void setText(String text) {
         textProperty.set(text);
     }

     public void bindTextContent(Signal<String> textSignal) {
         textProperty.bind(textSignal);
     }
 }
 

See Also:

• Serialized Form

Method Summary

Modifier and Type	Method	Description
void	bind(Signal<T> signal)	Binds a Signal's value to this property support and keeps the value synchronized with the signal value while the component is in attached state.
static <T> SignalPropertySupport<T>	create(Component owner, SerializableConsumer<T> valueChangeConsumer)	Creates a new instance of SignalPropertySupport for the given owner component and a value change consumer to be called when property value is updated.
T	get()	Gets the current value of this property support.
void	set(T value)	Sets the value of this property support.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

create

public static <T> SignalPropertySupport<T> create(Component owner,
 SerializableConsumer<T> valueChangeConsumer)

Creates a new instance of SignalPropertySupport for the given owner component and a value change consumer to be called when property value is updated. The property value is updated either manually with set(Object), or automatically via Signal value change while the owner component is in the attached state and signal is bound with bind(Signal).

Type Parameters:

T - the type of the property

Parameters:

owner - the owner component for which the value change consumer is applied, must not be null

valueChangeConsumer - the consumer to be called when the value changes, must not be null

Returns:

a new instance of SignalPropertySupport

See Also:

• bind(Signal)

bind

public void bind(Signal<T> signal)

Binds a Signal's value to this property support and keeps the value synchronized with the signal value while the component is in attached state. When the component is in detached state, signal value changes have no effect. null signal unbinds existing binding.

While a Signal is bound to a property support, any attempt to set value manually throws BindingActiveException. Same happens when trying to bind a new Signal while one is already bound.

Parameters:

signal - the signal to bind or null to unbind any existing binding

Throws:

BindingActiveException - thrown when there is already an existing binding

get

public T get()

Gets the current value of this property support.

Returns:

the current value

set

public void set(T value)

Sets the value of this property support.

Parameters:

value - the value to set

Throws:

BindingActiveException - thrown when there is an existing binding