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Provides support for defining properties and creating bindings between
sets of two properties.
Properties
A property is defined by creating an instance of a concrete implementation
of the {@link org.jdesktop.beansbinding.Property} class. This package
provides two concrete {@code Property} implementations of interest:
{@link org.jdesktop.beansbinding.BeanProperty} allows Java Bean properties
to be addressed by providing their path as a String.
{@link org.jdesktop.beansbinding.ELProperty} allows Java Bean properties
to be addressed similarly and then be used in various ways in an EL expression.
A simple {@code BeanProperty} that refers to a "firstName" Java Bean property,
might look like:
BeanProperty firstNameP = BeanProperty.create("firstName");
An {@code ELProperty} to combine the "firstName" and "lastName"
properties of a Java Bean into a full name, might look like:
ELProperty fullNameP = ELProperty.create("${firstName} ${lastName}");
These property objects can then be used to operate on a Java Bean having
the properties of interest. For example:
// prints the first name on the person object
System.out.println(firstNameP.getValue(person));
// prints the full name of the person object
System.out.println(fullNameP.getValue(person));
// sets the first name of the person object to "Duke"
firstNameP.setValue(person, "Duke");
// listen for changes to the person's full name
fullNameP.addPropertyStateListener(person, listener);
Both of these property implementations are designed to work with bean
properties that follow the Java Beans specification. Sometimes, however,
a property of interest on a bean outside of your control may not be exposed
in the correct way, and you want to adapt it for use in binding.
Other times you may want to extend the set of properties that a bean
exposes, simply for use in binding. These cases are provided for by
the org.jdesktop.beansbinding.ext
package.
Bindings
A binding is created between two {@code Property} instances, and the objects
on which the {@code Property} objects should operate, by creating an instance
of a concrete implementation of the {@code Binding} class. Once the binding is
realized, by a call to the {@code bind} method, a {@code Binding} starts
tracking changes to the properties on both ends, and a typical {@code Binding}
implementation will sync the properties with each other based on on some defined
strategy.
This package provides one concrete subclass of {@code Binding} called
{@link org.jdesktop.beansbinding.AutoBinding} which syncs the properties based
on a configurable update strategy. {@code AutoBindings} are created by
calling one of the static {@code createAutoBinding} methods in the
{@link org.jdesktop.beansbinding.Bindings} class. For example:
BeanProperty firstNameP = BeanProperty.create("firstName");
BeanProperty textP = BeanProperty.create("text");
Binding binding = Bindings.createAutoBinding(READ_WRITE, person, firstNameP, jTextField, textP);
binding.bind();
Before a value from a source property is set on a target property, it passes
through an optional {@link org.jdesktop.beansbinding.Converter} to convert
it between the source type and target type. Before a value passed from a
target property back to a source property, it passes first through the
optional {@code Converter} and then through an optional
{@link org.jdesktop.beansbinding.Validator}, which can reject invalid values.