Package com.vaadin.signals

Interface SignalFactory

Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface SignalFactory
Provides a signal instance based on a name. This encapsulates different strategies for creating instances that are e.g. synchronized across a cluster, shared within the same JVM, or isolated from any other instance.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final SignalFactory
    IN_MEMORY_EXCLUSIVE
    A signal factory that always returns a new instance that is not shared.
    static final SignalFactory
    IN_MEMORY_SHARED
    A signal factory that always returns the same signal for the same name within the same JVM.

  • Method Summary

    Modifier and Type
    Method
    Description
    default void
    clear()
    Removes all name associations.
    default <T> ListSignal<T>
    list(String name, Class<T> elementType)
    Gets a list signal with the given element type for the given name.
    default <T> MapSignal<T>
    map(String name, Class<T> elementType)
    Gets a map signal with the given element type for the given name.
    NodeSignal
    node(String name)
    Gets a node signal for the given name.
    default NumberSignal
    number(String name)
    Gets a number signal for the given name.
    default NumberSignal
    number(String name, double defaultValue)
    Gets a number signal for the given name and initializes it with the provided default value if the signal doesn't already have a value.
    default void
    remove(String name)
    Removes any previous association for the given name.
    default <T> ValueSignal<T>
    value(String name, Class<T> valueType)
    Gets a value signal of the given type for the given name.
    default <T> ValueSignal<T>
    value(String name, Class<T> valueType, T defaultValue)
    Gets a value signal of the given type for the given name and initializes it with the provided default value if the signal doesn't already have a value.
    default <T> ValueSignal<T>
    value(String name, T defaultValue)
    Gets a value signal for the given name and initializes it with the provided default value if the signal doesn't already have a value.

  • Field Details

    • IN_MEMORY_EXCLUSIVE

      static final SignalFactory IN_MEMORY_EXCLUSIVE
      A signal factory that always returns a new instance that is not shared. This factory does not support the optional removal methods.

    • IN_MEMORY_SHARED

      static final SignalFactory IN_MEMORY_SHARED
      A signal factory that always returns the same signal for the same name within the same JVM. This factory supports the optional removal methods.

  • Method Details

    • node

      NodeSignal node(String name)
      Gets a node signal for the given name.
      Parameters:
      name - the name to use, not null
      Returns:
      a node signal, not null

    • value

      default <T> ValueSignal<T> value(String name, Class<T> valueType)
      Gets a value signal of the given type for the given name.
      Type Parameters:
      T - the value type
      Parameters:
      name - the name to use, not null
      valueType - the value type to use, not null
      Returns:
      a value signal, not null

    • value

      default <T> ValueSignal<T> value(String name, Class<T> valueType, T defaultValue)
      Gets a value signal of the given type for the given name and initializes it with the provided default value if the signal doesn't already have a value. If the implementation returns an existing signal instance that already had a non-null value, then the provided default value is ignored.
      Type Parameters:
      T - the value type
      Parameters:
      name - the name to use, not null
      valueType - the value type to use, not null
      defaultValue - the default value to use, not null
      Returns:
      a value signal, not null

    • value

      default <T> ValueSignal<T> value(String name, T defaultValue)
      Gets a value signal for the given name and initializes it with the provided default value if the signal doesn't already have a value. If the implementation returns an existing signal instance that already had a non-null value, then the provided default value is ignored. The signal value type is based on the type (Object.getClass()) of the default value instance.
      Type Parameters:
      T - the value type
      Parameters:
      name - the name to use, not null
      defaultValue - the default value to use, not null
      Returns:
      a value signal, not null

    • number

      default NumberSignal number(String name)
      Gets a number signal for the given name.
      Parameters:
      name - the name to use, not null
      Returns:
      a number signal, not null

    • number

      default NumberSignal number(String name, double defaultValue)
      Gets a number signal for the given name and initializes it with the provided default value if the signal doesn't already have a value.
      Parameters:
      name - the name to use, not null
      defaultValue - the default value to use
      Returns:
      a number signal, not null

    • list

      default <T> ListSignal<T> list(String name, Class<T> elementType)
      Gets a list signal with the given element type for the given name.
      Type Parameters:
      T - the element type
      Parameters:
      name - the to use, not null
      elementType - the element type, not null
      Returns:
      a list signal, not null

    • map

      default <T> MapSignal<T> map(String name, Class<T> elementType)
      Gets a map signal with the given element type for the given name.
      Type Parameters:
      T - the element type
      Parameters:
      name - the to use, not null
      elementType - the element type, not null
      Returns:
      a map signal, not null

    • remove

      default void remove(String name) throws UnsupportedOperationException
      Removes any previous association for the given name. Removing an association typically means that memory previously associated with the name is freed and a subsequent invocation with the same name will create a new signal.

      This is an optional operation. Implementations that don't support removal throw UnsupportedOperationException.

      Parameters:
      name - the name to remove, not NullPointerException
      Throws:
      UnsupportedOperationException - if this implementation doesn't support removal

    • clear

      default void clear() throws UnsupportedOperationException
      Removes all name associations. Removing an association typically means that memory previously associated with the name is freed and a subsequent invocation with the same name will create a new signal.

      This is an optional operation. Implementations that don't support clearing may throw UnsupportedOperationException.

      Throws:
      UnsupportedOperationException - if this implementation doesn't support clearing