Package org.eclipse.core.databinding.observable.value

Class AbstractObservableValue<T>

java.lang.Object
org.eclipse.core.databinding.observable.AbstractObservable
org.eclipse.core.databinding.observable.value.AbstractObservableValue<T>
Type Parameters:
T - the type of value being observed
All Implemented Interfaces:
IObservable, IObservableValue<T>
Direct Known Subclasses:
AbstractVetoableValue, ComputedValue, DateAndTimeObservableValue, DuplexingObservableValue, LocalDateTimeObservableValue, SelectObservableValue, WritableValue
public abstract class AbstractObservableValue<T> extends AbstractObservable implements IObservableValue<T>

This class is thread safe. All state accessing methods must be invoked from the current realm. Methods for adding and removing listeners may be invoked from any thread.

Since:
1.0
Implementation Note:
If methods are added to the interface which this class implements then implementations of those methods must be added to this class.

  • Constructor Details

    • AbstractObservableValue

      public AbstractObservableValue()
      Constructs a new instance with the default realm.

    • AbstractObservableValue

      public AbstractObservableValue(Realm realm)
      Parameters:
      realm - the realm to use; not null

  • Method Details

    • addValueChangeListener

      public void addValueChangeListener(IValueChangeListener<? super T> listener)
      Specified by:
      addValueChangeListener in interface IObservableValue<T>
      Parameters:
      listener - the change listener to add; not null

    • removeValueChangeListener

      public void removeValueChangeListener(IValueChangeListener<? super T> listener)
      Specified by:
      removeValueChangeListener in interface IObservableValue<T>
      Parameters:
      listener - the change listener to remove; not null

    • setValue

      public final void setValue(T value)
      Description copied from interface: IObservableValue
      Sets the value. Must be invoked in the Realm of the observable.
      Specified by:
      setValue in interface IObservableValue<T>
      Parameters:
      value - the value to set

    • doSetValue

      protected void doSetValue(T value)
      Template method for setting the value of the observable. By default the method throws an UnsupportedOperationException.
      Parameters:
      value - the value to set

    • fireValueChange

      protected void fireValueChange(ValueDiff<T> diff)

    • getValue

      public final T getValue()
      Description copied from interface: IObservableValue
      Returns the value. Must be invoked in the Realm of the observable.
      Specified by:
      getValue in interface IObservableValue<T>
      Returns:
      the current value

    • doGetValue

      protected abstract T doGetValue()

    • isStale

      public boolean isStale()
      Description copied from interface: IObservable
      Returns whether the state of this observable is stale and is expected to change soon. A non-stale observable that becomes stale will notify its stale listeners. A stale object that becomes non-stale does so by changing its state and notifying its change listeners, it does not notify its stale listeners about becoming non-stale. Clients that do not expect asynchronous changes may ignore staleness of observable objects.
      Specified by:
      isStale in interface IObservable
      Returns:
      true if this observable's state is stale and will change soon.

    • fireChange

      protected void fireChange()
      Overrides:
      fireChange in class AbstractObservable

    • addListener

      protected void addListener(Object listenerType, IObservablesListener listener)
      Parameters:
      listenerType - arbitrary object to identify a type of the listener
      listener - the listener to add; not null

    • removeListener

      protected void removeListener(Object listenerType, IObservablesListener listener)
      Parameters:
      listenerType - arbitrary object to identify a type of the listener
      listener - the listener to remove; not null

    • hasListeners

      protected boolean hasListeners()

    • fireEvent

      protected void fireEvent(ObservableEvent event)

    • firstListenerAdded

      protected void firstListenerAdded()

    • lastListenerRemoved

      protected void lastListenerRemoved()

    • getRealm

      public Realm getRealm()
      Returns:
      Returns the realm.

    • clone

      protected Object clone() throws CloneNotSupportedException
      Overrides:
      clone in class Object
      Throws:
      CloneNotSupportedException