JavaFX 24 · javafx.beans.binding · APIdia, the JavaDoc alternative

Provides classes that create and operate on a Binding that calculates a value that depends on one or more sources.

Characteristics of Bindings

Bindings are assembled from one or more sources, usually called their dependencies. A binding observes its dependencies for changes and updates its own value according to changes in the dependencies.

Almost all bindings defined in this library require implementations of javafx.beans.Observable for their dependencies. There are two types of implementations already provided, the properties in the package javafx.beans.property and the observable collections (javafx.collections.ObservableList and javafx.collections.ObservableMap). Bindings also implement Observable and can again serve as sources for other bindings allowing to construct very complex bindings from simple ones.

Bindings in our implementation are always calculated lazily. That means, if a dependency changes, the result of a binding is not immediately recalculated, but it is marked as invalid. Next time the value of an invalid binding is requested, it is recalculated.

High Level API and Low Level API

The Binding API is roughly divided in two parts, the High Level Binding API and the Low Level Binding API. The High Level Binding API allows to construct simple bindings in an easy to use fashion. Defining a binding with the High Level API should be straightforward, especially when used in an IDE that provides code completion. Unfortunately it has its limitation and at that point the Low Level API comes into play. Experienced Java developers can use the Low Level API to define bindings, if the functionality of the High Level API is not sufficient or to improve the performance. The main goals of the Low Level API are fast execution and small memory footprint.

Following is an example of how both APIs can be used. Assuming we have four instances of javafx.beans.property.DoubleProperty a, b, c , and d, we can define a binding that calculates a*b + c*d with the High Level API for example like this:

NumberBinding result = Bindings.add (a.multiply(b), c.multiply(d));

Defining the same binding using the Low Level API could be done like this:


DoubleBinding foo = new DoubleBinding() {

    {
        super.bind(a, b, c, d);
    }

    @Override
    protected double computeValue() {
        return a.getValue() * b.getValue() + c.getValue() * d.getValue();
    }
};

Modifier and Type	Interface and Description
public interface	Binding< the type of the wrapped value T> A `Binding` calculates a value that depends on one or more sources.
public interface	NumberBinding A tagging interface to mark all Bindings that wrap a number-value.
public interface	NumberExpression `NumberExpression` is an `javafx.beans.value.ObservableNumberValue` plus additional convenience methods to generate bindings in a fluent style.

Class Summary

Modifier and Type	Class and Description
public class	Bindings Bindings is a helper class with a lot of utility functions to create simple bindings.
public abstract class	BooleanBinding Base class that provides most of the functionality needed to implement a `Binding` of a `boolean` value.
public abstract class	BooleanExpression `BooleanExpression` is an `javafx.beans.value.ObservableBooleanValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	DoubleBinding Base class that provides most of the functionality needed to implement a `Binding` of a `double` value.
public abstract class	DoubleExpression `DoubleExpression` is an `javafx.beans.value.ObservableDoubleValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	FloatBinding Base class that provides most of the functionality needed to implement a `Binding` of a `float` value.
public abstract class	FloatExpression `FloatExpression` is an `javafx.beans.value.ObservableFloatValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	IntegerBinding Base class that provides most of the functionality needed to implement a `Binding` of an `int` value.
public abstract class	IntegerExpression `IntegerExpression` is an `javafx.beans.value.ObservableIntegerValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	ListBinding< the type of the `List` element E> Base class that provides most of the functionality needed to implement a `Binding` of an `javafx.collections.ObservableList`.
public abstract class	ListExpression< the type of the `List` elements. E> `ListExpression` is an `javafx.beans.value.ObservableListValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	LongBinding Base class that provides most of the functionality needed to implement a `Binding` of a `long` value.
public abstract class	LongExpression `LongExpression` is an `javafx.beans.value.ObservableLongValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	MapBinding< the type of the key elements K, the type of the value elements V> Base class that provides most of the functionality needed to implement a `Binding` of an `javafx.collections.ObservableMap`.
public abstract class	MapExpression< the type of the key elements K, the type of the value elements V> `MapExpression` is an `javafx.beans.value.ObservableMapValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	NumberExpressionBase `NumberExpressionBase` contains convenience methods to generate bindings in a fluent style, that are common to all NumberExpression subclasses.
public abstract class	ObjectBinding< the type of the wrapped `Object` T> Base class that provides most of the functionality needed to implement a `Binding` of an `Object`.
public abstract class	ObjectExpression< the type of expression value T> `ObjectExpression` is an `javafx.beans.value.ObservableObjectValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	SetBinding< the type of the `Set` elements E> Base class that provides most of the functionality needed to implement a `Binding` of an `javafx.collections.ObservableSet`.
public abstract class	SetExpression< the type of the `Set` elements E> `SetExpression` is an `javafx.beans.value.ObservableSetValue` plus additional convenience methods to generate bindings in a fluent style.
public abstract class	StringBinding Base class that provides most of the functionality needed to implement a `Binding` of a `String`.
public abstract class	StringExpression `StringExpression` is an `javafx.beans.value.ObservableStringValue` plus additional convenience methods to generate bindings in a fluent style.
public class	When Starting point for a binding that calculates a ternary expression.

Package javafx.beans.binding

Characteristics of Bindings

High Level API and Low Level API

Interface Summary

Class Summary