javafx.beans.binding

Class MapBinding<K,V>

java.lang.Object

javafx.beans.binding.MapExpression<K,V>
- javafx.beans.binding.MapBinding<K,V>

Type Parameters:

K - the type of the key elements

All Implemented Interfaces:

Map<K,V>, Binding<ObservableMap<K,V>>, Observable, ObservableMapValue<K,V>, ObservableObjectValue<ObservableMap<K,V>>, ObservableValue<ObservableMap<K,V>>, ObservableMap<K,V>

public abstract class MapBinding<K,V>
extends MapExpression<K,V>
implements Binding<ObservableMap<K,V>>

Base class that provides most of the functionality needed to implement a Binding of an ObservableMap.

MapBinding provides a simple invalidation-scheme. An extending class can register dependencies by calling bind(Observable...). If one of the registered dependencies becomes invalid, this MapBinding 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

Property Summary

All MethodsInstance MethodsConcrete Methods
Type	Property and Description
`ReadOnlyBooleanProperty`	`empty` A boolean property that is `true`, if the map is empty.
`ReadOnlyIntegerProperty`	`size` An integer property that represents the size of the map.

Nested Class Summary
- Nested classes/interfaces inherited from interface java.util.Map
  Map.Entry<K,V>

Constructor Summary

Constructors
Constructor and Description

MapBinding()

Constructors
Constructor and Description
`MapBinding()`

Method Summary

All MethodsInstance MethodsAbstract MethodsConcrete Methods
Modifier and Type	Method and Description
`void`	`addListener(ChangeListener<? super ObservableMap<K,V>> listener)` Adds a `ChangeListener` which will be notified whenever the value of the `ObservableValue` changes.
`void`	`addListener(InvalidationListener listener)` Adds an `InvalidationListener` which will be notified whenever the `Observable` becomes invalid.
`void`	`addListener(MapChangeListener<? super K,? super V> listener)` Add a listener to this observable map.
`protected void`	`bind(Observable... dependencies)` Start observing the dependencies for changes.
`protected abstract ObservableMap<K,V>`	`computeValue()` Calculates the current value of this binding.
`void`	`dispose()` A default implementation of `dispose()` that is empty.
`ReadOnlyBooleanProperty`	`emptyProperty()` A boolean property that is `true`, if the map is empty.
`ObservableMap<K,V>`	`get()` Returns the result of `computeValue()`.
`ObservableList<?>`	`getDependencies()` A default implementation of `getDependencies()` that returns an empty `ObservableList`.
`void`	`invalidate()` Mark a binding as invalid.
`boolean`	`isValid()` Checks if a binding is valid.
`protected void`	`onInvalidating()` The method onInvalidating() can be overridden by extending classes to react, if this binding becomes invalid.
`void`	`removeListener(ChangeListener<? super ObservableMap<K,V>> listener)` Removes the given listener from the list of listeners, that are notified whenever the value of the `ObservableValue` changes.
`void`	`removeListener(InvalidationListener listener)` Removes the given listener from the list of listeners, that are notified whenever the value of the `Observable` becomes invalid.
`void`	`removeListener(MapChangeListener<? super K,? super V> listener)` Tries to removed a listener from this observable list.
`ReadOnlyIntegerProperty`	`sizeProperty()` An integer property that represents the size of the map.
`String`	`toString()` Returns a string representation of this `MapBinding` object.
`protected void`	`unbind(Observable... dependencies)` Stop observing the dependencies for changes.

Methods inherited from class javafx.beans.binding.MapExpression
asString, clear, containsKey, containsValue, entrySet, get, getSize, getValue, isEmpty, isEqualTo, isNotEqualTo, isNotNull, isNull, keySet, mapExpression, put, putAll, remove, size, valueAt, valueAt, values

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface javafx.beans.value.ObservableValue
getValue

Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll

Property Detail
- size
```
public ReadOnlyIntegerProperty sizeProperty
```
  Specified by:
  
  sizeProperty in class MapExpression<K,V>
  
  Returns:
  
  the property
- empty
```
public ReadOnlyBooleanProperty emptyProperty
```
  Specified by:
  
  emptyProperty in class MapExpression<K,V>

Constructor Detail
- MapBinding
```
public MapBinding()
```

Method Detail
- sizeProperty
```
public ReadOnlyIntegerProperty sizeProperty()
```
  Description copied from class: MapExpression
  
  An integer property that represents the size of the map.
  
  Specified by:
  
  sizeProperty in class MapExpression<K,V>
  
  Returns:
  
  the property
- emptyProperty
```
public ReadOnlyBooleanProperty emptyProperty()
```
  Description copied from class: MapExpression
  
  A boolean property that is true, if the map is empty.
  
  Specified by:
  
  emptyProperty in class MapExpression<K,V>
- addListener
```
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:
  
  Observable.removeListener(InvalidationListener)
- removeListener
```
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:
  
  Observable.addListener(InvalidationListener)
- addListener
```
public void addListener(ChangeListener<? super ObservableMap<K,V>> 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<ObservableMap<K,V>>
  
  Parameters:
  
  listener - The listener to register
  
  See Also:
  
  ObservableValue.removeListener(ChangeListener)
- removeListener
```
public void removeListener(ChangeListener<? super ObservableMap<K,V>> 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<ObservableMap<K,V>>
  
  Parameters:
  
  listener - The listener to remove
  
  See Also:
  
  ObservableValue.addListener(ChangeListener)
- addListener
```
public void addListener(MapChangeListener<? super K,? super V> listener)
```
  Description copied from interface: ObservableMap
  
  Add a listener to this observable map.
  
  Specified by:
  
  addListener in interface ObservableMap<K,V>
  
  Parameters:
  
  listener - the listener for listening to the list changes
- removeListener
```
public void removeListener(MapChangeListener<? super K,? super V> listener)
```
  Description copied from interface: ObservableMap
  
  Tries to removed a listener from this observable list. If the listener is not attached to this list, nothing happens.
  
  Specified by:
  
  removeListener in interface ObservableMap<K,V>
  
  Parameters:
  
  listener - a listener to remove
- bind
```
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
```
protected final void unbind(Observable... dependencies)
```
  Stop observing the dependencies for changes.
  
  Parameters:
  
  dependencies - the dependencies to stop observing
- dispose
```
public void dispose()
```
  A default implementation of dispose() that is empty.
  
  Specified by:
  
  dispose in interface Binding<ObservableMap<K,V>>
- getDependencies
```
public ObservableList<?> getDependencies()
```
  A default implementation of getDependencies() that returns an empty ObservableList.
  
  Specified by:
  
  getDependencies in interface Binding<ObservableMap<K,V>>
  
  Returns:
  
  an empty ObservableList
- get
```
public final ObservableMap<K,V> 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<ObservableMap<K,V>>
  
  Returns:
  
  the current value
- onInvalidating
```
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
```
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<ObservableMap<K,V>>
- isValid
```
public final boolean isValid()
```
  Description copied from interface: Binding
  
  Checks if a binding is valid.
  
  Specified by:
  
  isValid in interface Binding<ObservableMap<K,V>>
  
  Returns:
  
  true if the Binding is valid, false otherwise
- computeValue
```
protected abstract ObservableMap<K,V> computeValue()
```
  Calculates the current value of this binding.
  Classes extending MapBinding have to provide an implementation of computeValue.
  
  Returns:
  
  the current value
- toString
```
public String toString()
```
  Returns a string representation of this MapBinding object.
  
  Overrides:
  
  toString in class Object
  
  Returns:
  
  a string representation of this MapBinding object.

© 2008, 2025, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from JavaFX API Documentation.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Java, JavaFX and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.

Class MapBinding<K,V>

Property Summary

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Constructor Summary

Method Summary

Methods inherited from class javafx.beans.binding.MapExpression

Methods inherited from class java.lang.Object

Methods inherited from interface javafx.beans.value.ObservableValue

Methods inherited from interface java.util.Map

Property Detail

size

empty

Constructor Detail

MapBinding

Method Detail

sizeProperty

emptyProperty

addListener

removeListener

addListener

removeListener

addListener

removeListener

bind

unbind

dispose

getDependencies

get

onInvalidating

invalidate

isValid

computeValue

toString