javafx.beans.binding.DoubleBinding

All Implemented Interfaces:: Binding<Number>, NumberBinding, NumberExpression, Observable, ObservableDoubleValue, ObservableNumberValue, ObservableValue<Number>

public abstract class DoubleBinding
extends DoubleExpression
implements NumberBinding

Base class that provides most of the functionality needed to implement a Binding of a double value.

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

Below is a simple example of a DoubleBinding calculating the square- root of a ObservableNumberValue moo.

 
 final ObservableDoubleValue moo = ...;

 DoubleBinding foo = new DoubleBinding() {

     {
         super.bind(moo);
     }

     @Override
     protected double computeValue() {
         return Math.sqrt(moo.getValue());
     }
 };

Following is the same example with implementations for the optional methods Binding.getDependencies() and Binding.dispose().

 
 final ObservableDoubleValue moo = ...;

 DoubleBinding foo = new DoubleBinding() {

     {
         super.bind(moo);
     }

     @Override
     protected double computeValue() {
         return Math.sqrt(moo.getValue());
     }

     @Override
     public ObservableList<?> getDependencies() {
         return FXCollections.singletonObservableList(moo);
     }

     @Override
     public void dispose() {
         super.unbind(moo);
     }
 };

Since:: JavaFX 2.0
See Also:: Binding, NumberBinding, DoubleExpression

Constructor Summary

Constructors

Constructor Description

DoubleBinding()

Method Summary

Modifier and Type	Method	Description
`void`	`addListener(InvalidationListener listener)`	Adds an `InvalidationListener` which will be notified whenever the `Observable` becomes invalid.
`void`	`addListener(ChangeListener<? super Number> listener)`	Adds a `ChangeListener` which will be notified whenever the value of the `ObservableValue` changes.
`protected void`	`bind(Observable... dependencies)`	Start observing the dependencies for changes.
`protected abstract double`	`computeValue()`	Calculates the current value of this binding.
`void`	`dispose()`	A default implementation of `dispose()` that is empty.
`double`	`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(InvalidationListener listener)`	Removes the given listener from the list of listeners, that are notified whenever the value of the `Observable` becomes invalid.
`void`	`removeListener(ChangeListener<? super Number> listener)`	Removes the given listener from the list of listeners that are notified whenever the value of the `ObservableValue` changes.
`String`	`toString()`	Returns a string representation of this `DoubleBinding` object.
`protected void`	`unbind(Observable... dependencies)`	Stop observing the dependencies for changes.

Methods inherited from class javafx.beans.binding.DoubleExpression

add, add, add, add, add, asObject, divide, divide, divide, divide, divide, doubleExpression, doubleExpression, doubleValue, floatValue, getValue, intValue, longValue, multiply, multiply, multiply, multiply, multiply, negate, subtract, subtract, subtract, subtract, subtract

Methods inherited from class javafx.beans.binding.NumberExpressionBase

asString, asString, asString, greaterThan, greaterThan, greaterThan, greaterThan, greaterThan, greaterThanOrEqualTo, greaterThanOrEqualTo, greaterThanOrEqualTo, greaterThanOrEqualTo, greaterThanOrEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, lessThan, lessThan, lessThan, lessThan, lessThan, lessThanOrEqualTo, lessThanOrEqualTo, lessThanOrEqualTo, lessThanOrEqualTo, lessThanOrEqualTo, numberExpression

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface javafx.beans.binding.NumberExpression

add, add, add, add, add, asString, asString, asString, divide, divide, divide, divide, divide, greaterThan, greaterThan, greaterThan, greaterThan, greaterThan, greaterThanOrEqualTo, greaterThanOrEqualTo, greaterThanOrEqualTo, greaterThanOrEqualTo, greaterThanOrEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, isNotEqualTo, lessThan, lessThan, lessThan, lessThan, lessThan, lessThanOrEqualTo, lessThanOrEqualTo, lessThanOrEqualTo, lessThanOrEqualTo, lessThanOrEqualTo, multiply, multiply, multiply, multiply, multiply, negate, subtract, subtract, subtract, subtract, subtract

Methods inherited from interface javafx.beans.value.ObservableNumberValue

doubleValue, floatValue, intValue, longValue

Methods inherited from interface javafx.beans.value.ObservableValue

getValue

Constructor Details
- DoubleBinding
  
  public DoubleBinding()
Method Details
- 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 Number> 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<Number>
  
  Parameters:
  
  listener - The listener to register
  
  See Also:
  
  ObservableValue.removeListener(ChangeListener)
- removeListener
  
  public void removeListener(ChangeListener<? super Number> 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<Number>
  
  Parameters:
  
  listener - The listener to remove
  
  See Also:
  
  ObservableValue.addListener(ChangeListener)
- 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<Number>
- getDependencies
  
  public ObservableList<?> getDependencies()
  
  A default implementation of getDependencies() that returns an empty ObservableList.
  
  Specified by:
  
  getDependencies in interface Binding<Number>
  
  Returns:
  
  an empty ObservableList
- get
  
  public final double 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 ObservableDoubleValue
  
  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<Number>
- isValid
  
  public final boolean isValid()
  
  Description copied from interface: Binding
  
  Checks if a binding is valid.
  
  Specified by:
  
  isValid in interface Binding<Number>
  
  Returns:
  
  true if the Binding is valid, false otherwise
- computeValue
  
  protected abstract double computeValue()
  
  Calculates the current value of this binding.
  Classes extending DoubleBinding have to provide an implementation of computeValue.
  
  Returns:
  
  the current value
- toString
  
  public String toString()
  
  Returns a string representation of this DoubleBinding object.
  
  Overrides:
  
  toString in class Object
  
  Returns:
  
  a string representation of this DoubleBinding object.

Class DoubleBinding

Constructor Summary