Dynamic value provider

[ramgovind]

Is there way to generate fields dynamically using ValueProvider instead specifying the fields.

Please throw some idean on this.

[ramgovind]

Is there way to generate fields dynamically using ValueProvider instead of specifying fields.

Please throw some idea on this.

[ramgovind]

Is it possible to create own Custom*Impl by implementing ValueProvider<T, ?> so that this Impl can be used as per my need instead of generating own per field basis.

Please throw some idea on this.

[Colin Alworth]

What does your data model look like? If you have a regular Java bean-like object, with fields and getters/setters to define those fields, this isn't easy - GWT doesn't have runtime reflection. The PropertyAccess interface is intended to provide some automatically generated instances for getters and setters, but you have to describe the properties you want access to.

If your data model is a Map<String, ?>, so that you can put arbitrary objects in on the server, and want to read them out with a specific ValueProvider<T,?>, that is pretty easy to do. There are several forum posts that discuss this, as well as a blog post.

Some forum posts on this topic (Found by searching for ValueProvider in this same forum):
http://www.sencha.com/forum/showthre...l=1#post815861
http://www.sencha.com/forum/showthre...l=1#post815835
Blog post that discusses ideas around this - specifically check out the section titled ValueProvider:
http://www.sencha.com/blog/building-gxt-charts/

[ramgovind]

Thanks for replying with links.

[ramgovind]

How do I check null values before configuring into ColumnConfig.

ColumnConfig<MyProxy, Long> wParent = new ColumnConfig<MyProxy, Long>(
(ValueProvider<? super MyProxy, Long>)(props.parent() == null ? "None"
: props.parent()), 150, "Parent");

[Colin Alworth]

Generated PropertyAccess instances can never return null, so such a thing isn't necessary. Or, in this case, legal Java - you can't pass a String (i.e. "None") into the ColumnConfig constructor's first argument (which expects a ValueProvider).

What are you trying to do? Avoid drawing null? Avoid NullPointerExceptions? Can you give a specific example?

[ramgovind]

com.myprojet.shared.model.proxy.PersonProxy_person_personKey_ValueProviderImpl.getValue(PersonProxy_person_personKey_ValueProviderImpl.java:1)