# Interface SetChangeListener<E>

Type Parameters:
  `E` - the element type

All Known Implementing Classes:
  `WeakSetChangeListener`

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 SetChangeListener<E>
Interface that receives notifications of changes to an ObservableSet.

Since:
  JavaFX 2.1

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Interface
  Description
  `static class`
  `SetChangeListener.Change<E>`
  An elementary change done to an ObservableSet.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `onChanged(SetChangeListener.Change<? extends E> change)`
  Called after a change has been made to an ObservableSet.

- ## Method Details

  - ### onChanged

    void onChanged(SetChangeListener.Change<? extends E> change)
    Called after a change has been made to an ObservableSet. This method is called on every elementary change (add/remove) once. This means, complex changes like removeAll(Collection) or clear() may result in more than one call of onChanged method.
    Parameters:
      `change` - the change that was made