Class ListBinding<E>

java.lang.Object
javafx.beans.binding.ListExpression<E>
javafx.beans.binding.ListBinding<E>
Type Parameters:
E - the type of the List element
All Implemented Interfaces:
Iterable<E>, Collection<E>, List<E>, SequencedCollection<E>, Binding<ObservableList<E>>, Observable, ObservableListValue<E>, ObservableObjectValue<ObservableList<E>>, ObservableValue<ObservableList<E>>, ObservableList<E>

public abstract class ListBinding<E> extends ListExpression<E> implements Binding<ObservableList<E>>
Base class that provides most of the functionality needed to implement a Binding of an ObservableList.

ListBinding provides a simple invalidation-scheme. An extending class can register dependencies by calling bind(Observable...). If one of the registered dependencies becomes invalid, this ListBinding is marked as invalid. With unbind(Observable...) listening to dependencies can be stopped.

To provide a concrete implementation of this class, the method computeValue() has to be implemented to calculate the value of this binding based on the current state of the dependencies. It is called when get() is called for an invalid binding.

See DoubleBinding for an example how this base class can be extended.

Since:
JavaFX 2.1
See Also:
  • Property Details Link icon

  • Constructor Details Link icon

    • ListBinding Link icon

      public ListBinding()
      Creates a default ListBinding.
  • Method Details Link icon

    • sizeProperty Link icon

      public ReadOnlyIntegerProperty sizeProperty()
      Description copied from class: ListExpression
      An integer property that represents the size of the list.
      Specified by:
      sizeProperty in class ListExpression<E>
      Returns:
      the size property
    • emptyProperty Link icon

      public ReadOnlyBooleanProperty emptyProperty()
      Description copied from class: ListExpression
      A boolean property that is true, if the list is empty.
      Specified by:
      emptyProperty in class ListExpression<E>
      Returns:
      the empty property
    • addListener Link icon

      public void addListener(InvalidationListener listener)
      Description copied from interface: Observable
      Adds an InvalidationListener which will be notified whenever the Observable becomes invalid. If the same listener is added more than once, then it will be notified more than once. That is, no check is made to ensure uniqueness.

      Note that the same actual InvalidationListener instance may be safely registered for different Observables.

      The Observable stores a strong reference to the listener which will prevent the listener from being garbage collected and may result in a memory leak. It is recommended to either unregister a listener by calling removeListener after use or to use an instance of WeakInvalidationListener avoid this situation.

      Specified by:
      addListener in interface Observable
      Parameters:
      listener - The listener to register
      See Also:
    • removeListener Link icon

      public void removeListener(InvalidationListener listener)
      Description copied from interface: Observable
      Removes the given listener from the list of listeners, that are notified whenever the value of the Observable becomes invalid.

      If the given listener has not been previously registered (i.e. it was never added) then this method call is a no-op. If it had been previously added then it will be removed. If it had been added more than once, then only the first occurrence will be removed.

      Specified by:
      removeListener in interface Observable
      Parameters:
      listener - The listener to remove
      See Also:
    • addListener Link icon

      public void addListener(ChangeListener<? super ObservableList<E>> listener)
      Description copied from interface: ObservableValue
      Adds a ChangeListener which will be notified whenever the value of the ObservableValue changes. If the same listener is added more than once, then it will be notified more than once. That is, no check is made to ensure uniqueness.

      Note that the same actual ChangeListener instance may be safely registered for different ObservableValues.

      The ObservableValue stores a strong reference to the listener which will prevent the listener from being garbage collected and may result in a memory leak. It is recommended to either unregister a listener by calling removeListener after use or to use an instance of WeakChangeListener avoid this situation.

      Specified by:
      addListener in interface ObservableValue<E>
      Parameters:
      listener - The listener to register
      See Also:
    • removeListener Link icon

      public void removeListener(ChangeListener<? super ObservableList<E>> listener)
      Description copied from interface: ObservableValue
      Removes the given listener from the list of listeners that are notified whenever the value of the ObservableValue changes.

      If the given listener has not been previously registered (i.e. it was never added) then this method call is a no-op. If it had been previously added then it will be removed. If it had been added more than once, then only the first occurrence will be removed.

      Specified by:
      removeListener in interface ObservableValue<E>
      Parameters:
      listener - The listener to remove
      See Also:
    • addListener Link icon

      public void addListener(ListChangeListener<? super E> listener)
      Description copied from interface: ObservableList
      Add a listener to this observable list.
      Specified by:
      addListener in interface ObservableList<E>
      Parameters:
      listener - the listener for listening to the list changes
    • removeListener Link icon

      public void removeListener(ListChangeListener<? super E> listener)
      Description copied from interface: ObservableList
      Tries to remove a listener from this observable list. If the listener is not attached to this list, nothing happens.
      Specified by:
      removeListener in interface ObservableList<E>
      Parameters:
      listener - a listener to remove
    • bind Link icon

      protected final void bind(Observable... dependencies)
      Start observing the dependencies for changes. If the value of one of the dependencies changes, the binding is marked as invalid.
      Parameters:
      dependencies - the dependencies to observe
    • unbind Link icon

      protected final void unbind(Observable... dependencies)
      Stop observing the dependencies for changes.
      Parameters:
      dependencies - the dependencies to stop observing
    • dispose Link icon

      public void dispose()
      A default implementation of dispose() that is empty.
      Specified by:
      dispose in interface Binding<E>
    • getDependencies Link icon

      public ObservableList<?> getDependencies()
      A default implementation of getDependencies() that returns an empty ObservableList.
      Specified by:
      getDependencies in interface Binding<E>
      Returns:
      an empty ObservableList
    • get Link icon

      public final ObservableList<E> get()
      Returns the result of computeValue(). The method computeValue() is only called if the binding is invalid. The result is cached and returned if the binding did not become invalid since the last call of get().
      Specified by:
      get in interface ObservableObjectValue<E>
      Returns:
      the current value
    • onInvalidating Link icon

      protected void onInvalidating()
      The method onInvalidating() can be overridden by extending classes to react, if this binding becomes invalid. The default implementation is empty.
    • invalidate Link icon

      public final void invalidate()
      Description copied from interface: Binding
      Mark a binding as invalid. This forces the recalculation of the value of the Binding next time it is request.
      Specified by:
      invalidate in interface Binding<E>
    • isValid Link icon

      public final boolean isValid()
      Description copied from interface: Binding
      Checks if a binding is valid.
      Specified by:
      isValid in interface Binding<E>
      Returns:
      true if the Binding is valid, false otherwise
    • computeValue Link icon

      protected abstract ObservableList<E> computeValue()
      Calculates the current value of this binding.

      Classes extending ListBinding have to provide an implementation of computeValue.

      Returns:
      the current value
    • toString Link icon

      public String toString()
      Returns a string representation of this ListBinding object.
      Overrides:
      toString in class Object
      Returns:
      a string representation of this ListBinding object.