Contact us
Create app
com.vaadin.signals.
Package com.vaadin.signals

Class NumberSignal

java.lang.Object
com.vaadin.signals.Signal<T>
com.vaadin.signals.ValueSignal<Double>
com.vaadin.signals.NumberSignal
public class NumberSignal extends ValueSignal<Double>

A signal containing a numeric value. The value is updated as a single atomic change. In addition to the regular ValueSignal operation, this class also supports atomically incrementing the value.

  • Constructor Details

    • NumberSignal

      public NumberSignal()

      Creates a new number signal with a zero value. The signal does not support clustering.

    • NumberSignal

      public NumberSignal(double initialValue)

      Creates a new number signal with the given value. The signal does not support clustering.

      Parameters:

      initialValue - the initial value

    • NumberSignal

      protected NumberSignal(SignalTree tree, Id id, Predicate<SignalCommand> validator)

      Creates a new number signal instance with the given id and validator for the given signal tree.

      Parameters:

      tree - the signal tree that contains the value for this signal, not null

      id - the id of the signal node within the signal tree, not null

      validator - the validator to check operations submitted to this singal, not null

  • Method Details

    • incrementBy

      public SignalOperation<Double> incrementBy(double delta)

      Atomically increments the value of this signal by the given delta amount. The value is decremented if the delta is negative. The result of the returned operation will be resolved with the update value at the time when this operation was confirmed.

      Parameters:

      delta - the increment amount

      Returns:

      an operation containing the eventual result

    • value

      public Double value()

      Description copied from class: Signal

      Gets the current value of this signal. The value is read in a way that takes the current transaction into account and in the case of clustering also changes that have been submitted to the cluster but not yet confirmed.

      Reading the value in a regular (i.e. Transaction.Type.STAGED) transaction makes the transaction depend on the value so that the transaction fails in case the signal value is changed concurrently.

      Reading the value inside an Signal.effect(Runnable) or Signal.computed(Supplier) callback sets up that effect or computed signal to depend on the signal.

      Overrides:

      value in class Signal<Double>

      Returns:

      the signal value

    • valueAsInt

      public int valueAsInt()

      Gets the value of this signal as an integer. This method works in the same way was value() with regards to transactions and dependency tracking.

      Returns:

      the signal value as an integer

    • value

      public SignalOperation<Double> value(int value)

      Sets the value of this signal as an integer. This method works in the same way was the regular value setter with regards to transactions.

      Parameters:

      value - the integer value to set

      Returns:

      an operation containing the eventual result

    • withValidator

      public NumberSignal withValidator(Predicate<SignalCommand> validator)

      Wraps this signal with a validator. The validator is used to check all value changing commands issued through the new signal instance. If this signal has a validator, then the new signal will use both validators. Note that due to the way validators are retained by ValueSignal.asNode(), there's a possibility that the validator also receives commands that cannot be directly issued for a number signal.

      This signal will keep its current configuration and changes applied through this instance will be visible through the wrapped instance.

      Overrides:

      withValidator in class ValueSignal<Double>

      Parameters:

      validator - the validator to use, not null

      Returns:

      a new number signal that uses the validator, not null

    • asReadonly

      public NumberSignal asReadonly()

      Wraps this signal to not accept changes.

      This signal will keep its current configuration and changes applied through this instance will be visible through the wrapped instance.

      Overrides:

      asReadonly in class ValueSignal<Double>

      Returns:

      the new readonly number signal, not null

    • mapIntValue

      public <C> Signal<C> mapIntValue(IntFunction<C> mapper)

      Creates a computed signal based on an integer mapper function that is passed the value of this signal. If the mapper function accesses other signal values, then the computed signal will also depend on those signals.

      Type Parameters:

      C - the computed signal type

      Parameters:

      mapper - the integer mapper function to use, not null

      Returns:

      the computed signal, not null

    • equals

      public boolean equals(Object obj)

      Overrides:

      equals in class ValueSignal<Double>

    • hashCode

      public int hashCode()

      Overrides:

      hashCode in class ValueSignal<Double>

    • toString

      public String toString()

      Overrides:

      toString in class ValueSignal<Double>

Copyright © 2025. All rights reserved.