Module javafx.base
Package javafx.collections

## Interface MapChangeListener<K,​V>

- Type Parameters:
    `K` - the key element type
    `V` - the value element type
  All Known Implementing Classes:
    `WeakMapChangeListener`
  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 MapChangeListener<K,​V>

  Interface that receives notifications of changes to an ObservableMap.
  Since:
    JavaFX 2.0

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Interface | Description
    --- | --- | ---
    `static class` | `MapChangeListener.Change<K,​V>` | An elementary change done to an ObservableMap.

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `onChanged​(MapChangeListener.Change<? extends K,​? extends V> change)` | Called after a change has been made to an ObservableMap.

- - ### Method Detail

    - #### onChanged

          void onChanged​(MapChangeListener.Change<? extends K,​? extends V> change)

      Called after a change has been made to an ObservableMap. This method is called on every elementary change (put/remove) once. This means, complex changes like keySet().removeAll(Collection) or clear() may result in more than one call of onChanged method.
      Parameters:
        `change` - the change that was made