- 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
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Properties declared in class javafx.beans.binding.MapExpression
empty, size
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Constructor Summary
Constructors Constructor Description MapBinding()Creates a defaultMapBinding.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description 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.ObservableMap<K,V>get()Returns the result ofcomputeValue().ObservableList<?>getDependencies()A default implementation ofgetDependencies()that returns an emptyObservableList.protected voidonInvalidating()The method onInvalidating() can be overridden by extending classes to react, if this binding becomes invalid.StringtoString()Returns a string representation of thisMapBindingobject.protected voidunbind(Observable... dependencies)Stop observing the dependencies for changes.-
Methods declared in class javafx.beans.binding.MapExpression
asString, emptyProperty, getSize, isEqualTo, isNotEqualTo, isNotNull, isNull, mapExpression, sizeProperty, valueAt, valueAt
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Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods declared in interface javafx.beans.binding.Binding
invalidate, isValid
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Methods declared in interface java.util.Map
clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values
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Methods declared in interface javafx.beans.Observable
addListener, removeListener
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Methods declared in interface javafx.collections.ObservableMap
addListener, removeListener
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Methods declared in interface javafx.beans.value.ObservableValue
addListener, getValue, removeListener
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Method Detail
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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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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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