Package javafx.beans.binding

Class Bindings

java.lang.Object

javafx.beans.binding.Bindings

public final class Bindings
extends Object

Bindings is a helper class with a lot of utility functions to create simple bindings.

Usually there are two possibilities to define the same operation: the Fluent API and the the factory methods in this class. This allows a developer to define complex expression in a way that is most easy to understand. For instance the expression result = a*b + c*d can be defined using only the Fluent API:

DoubleBinding result = a.multiply(b).add(c.multiply(d));

Or using only factory methods in Bindings:

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

Or mixing both possibilities:

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

The main difference between using the Fluent API and using the factory methods in this class is that the Fluent API requires that at least one of the operands is an Expression (see javafx.beans.binding). (Every Expression contains a static method that generates an Expression from an ObservableValue.)

Also if you watched closely, you might have noticed that the return type of the Fluent API is different in the examples above. In a lot of cases the Fluent API allows to be more specific about the returned type (see NumberExpression for more details about implicit casting.

Since:

JavaFX 2.0

See Also:

• Binding
• NumberBinding

Method Summary

Modifier and Type	Method	Description
static BooleanBinding	and(ObservableBooleanValue op1, ObservableBooleanValue op2)	Creates a BooleanBinding that calculates the conditional-AND operation on the value of two instance of ObservableBooleanValue.
static <T> void	bindBidirectional(Property<String> stringProperty, Property<T> otherProperty, StringConverter<T> converter)	Generates a bidirectional binding (or "bind with inverse") between a String-Property and another Property using the specified StringConverter for conversion.
static <T> void	bindBidirectional(Property<T> property1, Property<T> property2)	Generates a bidirectional binding (or "bind with inverse") between two instances of Property.
static BooleanBinding	createBooleanBinding(Callable<Boolean> func, Observable... dependencies)	Helper function to create a custom BooleanBinding.
static NumberBinding	divide(ObservableNumberValue op1, int op2)	Creates a new NumberBinding that calculates the division of the value of a ObservableNumberValue and a constant value.
static BooleanBinding	isEmpty(ObservableStringValue op)	Creates a new BooleanBinding that holds true if the value of a ObservableStringValue is empty.
static <E> BooleanBinding	isEmpty(ObservableList<E> op)	Creates a new BooleanBinding that holds true if a given ObservableList is empty.
static BooleanBinding	isNotEmpty(ObservableStringValue op)	Creates a new BooleanBinding that holds true if the value of a ObservableStringValue is not empty.
static BooleanBinding	not(ObservableBooleanValue op)	Creates a BooleanBinding that calculates the inverse of the value of a ObservableBooleanValue.
static BooleanBinding	or(ObservableBooleanValue op1, ObservableBooleanValue op2)	Creates a BooleanBinding that calculates the conditional-AND operation on the value of two instance of ObservableBooleanValue.
static void	unbindBidirectional(Object property1, Object property2)	Delete a bidirectional binding that was previously defined with bindBidirectional(Property, Property) or invalid @link #bindBidirectional(javafx.beans.property.Property, javafx.beans.property.Property, java.text.Format) .
static <T> void	unbindBidirectional(Property<T> property1, Property<T> property2)	Delete a bidirectional binding that was previously defined with bindBidirectional(Property, Property).

Methods inherited from class java.lang.Object

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

Method Details

createBooleanBinding

public static BooleanBinding createBooleanBinding(Callable<Boolean> func,
 Observable... dependencies)

Helper function to create a custom BooleanBinding.

Parameters:

func - The function that calculates the value of this binding

dependencies - The dependencies of this binding

Returns:

The generated binding

Since:

JavaFX 2.1

not

public static BooleanBinding not(ObservableBooleanValue op)

Creates a BooleanBinding that calculates the inverse of the value of a ObservableBooleanValue.

Parameters:

op - the ObservableBooleanValue

Returns:

the new BooleanBinding

Throws:

NullPointerException - if the operand is null

bindBidirectional

public static <T> void bindBidirectional(Property<T> property1,
 Property<T> property2)

Generates a bidirectional binding (or "bind with inverse") between two instances of Property.

A bidirectional binding is a binding that works in both directions. If two properties a and b are linked with a bidirectional binding and the value of a changes, b is set to the same value automatically. And vice versa, if b changes, a is set to the same value.

A bidirectional binding can be removed with unbindBidirectional(Property, Property).

Note: this implementation of a bidirectional binding behaves differently from all other bindings here in two important aspects. A property that is linked to another property with a bidirectional binding can still be set (usually bindings would throw an exception). Secondly bidirectional bindings are calculated eagerly, i.e. a bound property is updated immediately.

Type Parameters:

T - the types of the properties

Parameters:

property1 - the first Property<T>

property2 - the second Property<T>

Throws:

NullPointerException - if one of the properties is null

IllegalArgumentException - if both properties are equal

unbindBidirectional

public static <T> void unbindBidirectional(Property<T> property1,
 Property<T> property2)

Delete a bidirectional binding that was previously defined with bindBidirectional(Property, Property).

Type Parameters:

T - the types of the properties

Parameters:

property1 - the first Property<T>

property2 - the second Property<T>

Throws:

NullPointerException - if one of the properties is null

IllegalArgumentException - if both properties are equal

unbindBidirectional

public static void unbindBidirectional(Object property1,
 Object property2)

Delete a bidirectional binding that was previously defined with bindBidirectional(Property, Property) or

invalid @link

#bindBidirectional(javafx.beans.property.Property, javafx.beans.property.Property, java.text.Format)

.

Parameters:

property1 - the first Property<T>

property2 - the second Property<T>

Throws:

NullPointerException - if one of the properties is null

IllegalArgumentException - if both properties are equal

Since:

JavaFX 2.1

bindBidirectional

public static <T> void bindBidirectional(Property<String> stringProperty,
 Property<T> otherProperty,
 StringConverter<T> converter)

Generates a bidirectional binding (or "bind with inverse") between a String-Property and another Property using the specified StringConverter for conversion.

A bidirectional binding is a binding that works in both directions. If two properties a and b are linked with a bidirectional binding and the value of a changes, b is set to the same value automatically. And vice versa, if b changes, a is set to the same value.

A bidirectional binding can be removed with unbindBidirectional(Object, Object).

Note: this implementation of a bidirectional binding behaves differently from all other bindings here in two important aspects. A property that is linked to another property with a bidirectional binding can still be set (usually bindings would throw an exception). Secondly bidirectional bindings are calculated eagerly, i.e. a bound property is updated immediately.

Parameters:

stringProperty - the String Property

otherProperty - the other (non-String) Property

converter - the StringConverter used to convert between the properties

Throws:

NullPointerException - if one of the properties or the converter is null

IllegalArgumentException - if both properties are equal

Since:

JavaFX 2.1

and

public static BooleanBinding and(ObservableBooleanValue op1,
 ObservableBooleanValue op2)

Creates a BooleanBinding that calculates the conditional-AND operation on the value of two instance of ObservableBooleanValue.

Parameters:

op1 - first ObservableBooleanValue

op2 - second ObservableBooleanValue

Returns:

the new BooleanBinding

Throws:

NullPointerException - if one of the operands is null

or

public static BooleanBinding or(ObservableBooleanValue op1,
 ObservableBooleanValue op2)

Creates a BooleanBinding that calculates the conditional-AND operation on the value of two instance of ObservableBooleanValue.

Parameters:

op1 - first ObservableBooleanValue

op2 - second ObservableBooleanValue

Returns:

the new BooleanBinding

Throws:

NullPointerException - if one of the operands is null

divide

public static NumberBinding divide(ObservableNumberValue op1,
 int op2)

Creates a new NumberBinding that calculates the division of the value of a ObservableNumberValue and a constant value.

Parameters:

op1 - the constant value

op2 - the ObservableNumberValue

Returns:

the new NumberBinding

Throws:

NullPointerException - if the ObservableNumberValue is null

isEmpty

public static <E> BooleanBinding isEmpty(ObservableList<E> op)

Creates a new BooleanBinding that holds true if a given ObservableList is empty.

Type Parameters:

E - type of the List elements

Parameters:

op - the ObservableList

Returns:

the new BooleanBinding

Throws:

NullPointerException - if the ObservableList is null

Since:

JavaFX 2.1

isEmpty

public static BooleanBinding isEmpty(ObservableStringValue op)

Creates a new BooleanBinding that holds true if the value of a ObservableStringValue is empty.

Note: In this comparison a String that is null is considered to be empty.

Parameters:

op - the ObservableStringValue

Returns:

the new BooleanBinding

Throws:

NullPointerException - if the ObservableStringValue is null

Since:

JavaFX 8.0

isNotEmpty

public static BooleanBinding isNotEmpty(ObservableStringValue op)

Creates a new BooleanBinding that holds true if the value of a ObservableStringValue is not empty.

Note: In this comparison a String that is null is considered to be empty.

Parameters:

op - the ObservableStringValue

Returns:

the new BooleanBinding

Throws:

NullPointerException - if the ObservableStringValue is null

Since:

JavaFX 8.0