Module is.codion.common.reactive
Package is.codion.common.reactive.observer

Interface Observable<T>

Type Parameters:
T - the value type
All Superinterfaces:
Observer<T>
All Known Subinterfaces:
CalendarPanel.CalendarDate, CalendarPanel.CalendarDateTime, CalendarPanel.CalendarZonedDateTime, ComponentValue<C,T>, EntityConditionModel.ConditionValue, EntityEditModel.EditorValue<T>, EntityEditModel.EntityEditor, FilterModel.FilteredItems<T>, FilterModel.IncludedItems<T>, FilterModel.IncludePredicate<T>, FilterTableColumnModel.ColumnSelection.ColumnIndex, FilterTableColumnModel.HiddenColumns<C>, FilterTableColumnModel.VisibleColumns<C>, FilterTableSearchModel.Results, ImagePane.ImageValue, MultiSelection.Indexes, MultiSelection.Items<R>, ObservableValueCollection<T,C>, ObservableValueList<T>, ObservableValueSet<T>, Value<T>, ValueCollection<T,C>, ValueList<T>, ValueSet<T>
All Known Implementing Classes:
AbstractComponentValue, AbstractTextComponentValue, AbstractValue, PropertyValue
public interface Observable<T> extends Observer<T>
A wrapper for a value, providing a change observer.

Thread Safety: Listener management is thread-safe, value access thread-safety is implementation dependent. 

   class Person {
       private final Event<String> nameChanged = Event.event();

       private String name;

       public String getName() {
           return name;
       }

       public void setName(String name) {
           this.name = name;
           nameChanged.accept(name);
      }
   }

   Person person = new Person();

   Observable<String> observableName = new Observable<>() {
       @Override
       public String get() {
           return person.getName();
       }

       @Override
       public Observer<String> observer() {
           return person.nameChanged.observer();
       }
  };

  observableName.addConsumer(newName ->
          System.out.println("Name changed to " + newName));

  • Method Details

    • get

      @Nullable T get()
      Returns:
      the value

    • getOrThrow

      default T getOrThrow()
      Returns:
      the value
      Throws:
      NoSuchElementException - if no value is present

    • getOrThrow

      default T getOrThrow(String message)
      Parameters:
      message - the error message to use when throwing
      Returns:
      the value
      Throws:
      NoSuchElementException - if no value is present

    • optional

      default Optional<T> optional()
      Returns:
      an Optional wrapping this value.

    • isNull

      default boolean isNull()
      Returns:
      true if the underlying value is null.

    • isNullable

      default boolean isNullable()
      If false then get() is guaranteed to never return null.
      Returns:
      true if this observable can be null

    • is

      default boolean is(@Nullable T value)
      Returns true if the underlying value is equal to the given one. Note that null == null.
      Parameters:
      value - the value
      Returns:
      true if the underlying value is equal to the given one

    • isNot

      default boolean isNot(@Nullable T value)
      Returns true if the underlying value is NOT equal to the given one. Note that null == null.
      Parameters:
      value - the value
      Returns:
      true if the underlying value is NOT equal to the given one