- java.lang.Object
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- javafx.beans.binding.MapExpression<K,V>
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- javafx.beans.binding.MapBinding<K,V>
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- Type Parameters:
K- the type of the key elementsV- the type of the value 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 aBindingof anObservableMap.MapBindingprovides a simple invalidation-scheme. An extending class can register dependencies by callingbind(Observable...). If one of the registered dependencies becomes invalid, thisMapBindingis marked as invalid. Withunbind(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 whenget()is called for an invalid binding.See
DoubleBindingfor an example how this base class can be extended.- Since:
- JavaFX 2.1
- See Also:
Binding,MapExpression
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Property Summary
Properties Type Property Description ReadOnlyBooleanPropertyemptyA boolean property that istrue, if the map is empty.ReadOnlyIntegerPropertysizeAn integer property that represents the size of the map.
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Constructor Summary
Constructors Constructor Description MapBinding()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description voidaddListener(InvalidationListener listener)Adds anInvalidationListenerwhich will be notified whenever theObservablebecomes invalid.voidaddListener(ChangeListener<? super ObservableMap<K,V>> listener)Adds aChangeListenerwhich will be notified whenever the value of theObservableValuechanges.voidaddListener(MapChangeListener<? super K,? super V> listener)Add a listener to this observable map.protected voidbind(Observable... dependencies)Start observing the dependencies for changes.protected abstract ObservableMap<K,V>computeValue()Calculates the current value of this binding.voiddispose()A default implementation ofdispose()that is empty.ReadOnlyBooleanPropertyemptyProperty()A boolean property that istrue, if the map is empty.ObservableMap<K,V>get()Returns the result ofcomputeValue().ObservableList<?>getDependencies()A default implementation ofgetDependencies()that returns an emptyObservableList.voidinvalidate()Mark a binding as invalid.booleanisValid()Checks if a binding is valid.protected voidonInvalidating()The method onInvalidating() can be overridden by extending classes to react, if this binding becomes invalid.voidremoveListener(InvalidationListener listener)Removes the given listener from the list of listeners, that are notified whenever the value of theObservablebecomes invalid.voidremoveListener(ChangeListener<? super ObservableMap<K,V>> listener)Removes the given listener from the list of listeners that are notified whenever the value of theObservableValuechanges.voidremoveListener(MapChangeListener<? super K,? super V> listener)Tries to removed a listener from this observable map.ReadOnlyIntegerPropertysizeProperty()An integer property that represents the size of the map.StringtoString()Returns a string representation of thisMapBindingobject.protected voidunbind(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
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll
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Methods inherited from interface javafx.beans.value.ObservableValue
getValue
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Property Detail
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size
public ReadOnlyIntegerProperty sizeProperty
- Specified by:
sizePropertyin classMapExpression<K,V>- See Also:
MapExpression.getSize()
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empty
public ReadOnlyBooleanProperty emptyProperty
- Specified by:
emptyPropertyin classMapExpression<K,V>- See Also:
MapExpression.isEmpty()
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Method Detail
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sizeProperty
public ReadOnlyIntegerProperty sizeProperty()
Description copied from class:MapExpressionAn integer property that represents the size of the map.- Specified by:
sizePropertyin classMapExpression<K,V>- See Also:
MapExpression.getSize()
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emptyProperty
public ReadOnlyBooleanProperty emptyProperty()
Description copied from class:MapExpressionA boolean property that istrue, if the map is empty.- Specified by:
emptyPropertyin classMapExpression<K,V>- See Also:
MapExpression.isEmpty()
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addListener
public void addListener(InvalidationListener listener)
Description copied from interface:ObservableAdds anInvalidationListenerwhich will be notified whenever theObservablebecomes 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
InvalidationListenerinstance may be safely registered for differentObservables.The
Observablestores 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 callingremoveListenerafter use or to use an instance ofWeakInvalidationListeneravoid this situation.- Specified by:
addListenerin interfaceObservable- Parameters:
listener- The listener to register- See Also:
Observable.removeListener(InvalidationListener)
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removeListener
public void removeListener(InvalidationListener listener)
Description copied from interface:ObservableRemoves the given listener from the list of listeners, that are notified whenever the value of theObservablebecomes 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:
removeListenerin interfaceObservable- Parameters:
listener- The listener to remove- See Also:
Observable.addListener(InvalidationListener)
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addListener
public void addListener(ChangeListener<? super ObservableMap<K,V>> listener)
Description copied from interface:ObservableValueAdds aChangeListenerwhich will be notified whenever the value of theObservableValuechanges. 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
ChangeListenerinstance may be safely registered for differentObservableValues.The
ObservableValuestores 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 callingremoveListenerafter use or to use an instance ofWeakChangeListeneravoid this situation.- Specified by:
addListenerin interfaceObservableValue<K>- Parameters:
listener- The listener to register- See Also:
ObservableValue.removeListener(ChangeListener)
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removeListener
public void removeListener(ChangeListener<? super ObservableMap<K,V>> listener)
Description copied from interface:ObservableValueRemoves the given listener from the list of listeners that are notified whenever the value of theObservableValuechanges.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:
removeListenerin interfaceObservableValue<K>- Parameters:
listener- The listener to remove- See Also:
ObservableValue.addListener(ChangeListener)
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addListener
public void addListener(MapChangeListener<? super K,? super V> listener)
Description copied from interface:ObservableMapAdd a listener to this observable map.- Specified by:
addListenerin interfaceObservableMap<K,V>- Parameters:
listener- the listener for listening to the list changes
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removeListener
public void removeListener(MapChangeListener<? super K,? super V> listener)
Description copied from interface:ObservableMapTries to removed a listener from this observable map. If the listener is not attached to this map, nothing happens.- Specified by:
removeListenerin interfaceObservableMap<K,V>- Parameters:
listener- a listener to remove
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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
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unbind
protected final void unbind(Observable... dependencies)
Stop observing the dependencies for changes.- Parameters:
dependencies- the dependencies to stop observing
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dispose
public void dispose()
A default implementation ofdispose()that is empty.
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getDependencies
public ObservableList<?> getDependencies()
A default implementation ofgetDependencies()that returns an emptyObservableList.- Specified by:
getDependenciesin interfaceBinding<K>- Returns:
- an empty
ObservableList
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get
public final ObservableMap<K,V> get()
Returns the result ofcomputeValue(). The methodcomputeValue()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 ofget().- Specified by:
getin interfaceObservableObjectValue<K>- Returns:
- the current value
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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.
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invalidate
public final void invalidate()
Description copied from interface:BindingMark a binding as invalid. This forces the recalculation of the value of theBindingnext time it is request.- Specified by:
invalidatein interfaceBinding<K>
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isValid
public final boolean isValid()
Description copied from interface:BindingChecks if a binding is valid.
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computeValue
protected abstract ObservableMap<K,V> computeValue()
Calculates the current value of this binding.Classes extending
MapBindinghave to provide an implementation ofcomputeValue.- Returns:
- the current value
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