JavaBeanPropertyAdapter

[Tom Schindl]

Would it be possible to also relax the restriction to not require the
"Bean" have a property change listener (then it is not a Bean anymore
but a simple POJO).

This way a sync can only happen from UI to model but when we talk about
DTOs and stuff they normally tend to not be beans (they don't fire
property change events) and so could be used.

Naturally in that case the nameing would be different and maybe this
would make a new request.

Tom

Am 14.12.11 12:24, schrieb Michael Heinrichs:
> Hi,
> 
> I would like to add two new classes (javafx.beans.property.JavaBeanPropertyAdapter and javafx.beans.property.JavaBeanReadOnlyPropertyAdapter) to provide ready to use support for Java Bean integration (http://javafx-jira.kenai.com/browse/RT-14004). The names are just working titles, I am open to any suggestion.
> 
> Both classes allow to create adapters for conventional Java Bean properties and map them to JavaFX Properties.
> 
> The read only case is pretty straightforward. The Java Bean property has to be a bound, read-only property, i.e. it has to have a getter and support PropertyChangeListeners. I propose the following API:
> 
> public class JavaBeanReadOnlyPropertyAdapter<T> {
>     public JavaBeanReadOnlyPropertyAdapter(Class<?> clazz, String propertyName);
>     public JavaBeanReadOnlyPropertyAdapter(Class<?> clazz, String propertyName, String getterName);
>     public JavaBeanReadOnlyPropertyAdapter(Class<?> clazz, String propertyName, Method getter);
> 
>     public ReadOnlyObjectProperty<T> createProperty(Object bean);
> 
>     public static <T> ReadOnlyObjectProperty<T> createProperty(Object bean, String propertyName);
> }
> 
> To use it, one first has to create a JavaBeanReadOnlyPropertyAdapter, passing the class and the propertyName, if the Java Bean follows the Java Bean convention. If not, one can also pass in the name of the getter method or the getter directly. In a second step, one creates the property by calling createProperty(). The static method is for convenience, if only a single property is needed.
> 
> 
> 
> The writable case is a little more complex, because we are not in full control of a Java Bean property. The Java Bean property has to be bound and writable. If you want to define a unidirectional binding for a Java Bean property, it also has to be constrained (i.e. support VetoableChangeListeners).
> 
> Bindings for Java Bean properties will be slightly different than our usual bindings: they will be eager and they may become out-of-sync. Let's say we have a Java Bean Property p, that is bound to an ObservableValue v. Internally we hook a listener to v and propagate all changes to p by calling its setter (that is why it will be eager). If now p does not accept the value from v, p and v will be out-of-sync. Especially the last point bothers my, but I guess there is no way to ensure synchronization.
> 
> The API and usage is similar to the read only case above. Only the method isBindable() is new, which returns true, if the Java Bean property is constrained and can therefore be bound unidirectionally. (If you try to define a unidirectional binding for a Java Bean property, that is not constrained, an UnsupportedOperationException is thrown in bind().)
> 
> public class JavaBeanPropertyAdapter<T> {
>     public JavaBeanPropertyAdapter(Class<?> clazz, String propertyName);
>     public JavaBeanPropertyAdapter(Class<?> clazz, String propertyName, String getterName, String setterName);
>    public JavaBeanPropertyAdapter(Class<?> clazz, String propertyName, Method getter, Method setter);
> 
>     public ObjectProperty<T> createProperty(Object bean);
>     public boolean isBindable();
> 
>     public static <T> ObjectProperty<T> createProperty(Object bean, String propertyName);
> }
> 
> 
> 
> What do you think?
> 
> Thanks,
> Michael


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