Overriding Control Hints of a View Object on the fly

I recently came across a use case where the requirement was to fetch Attribute Hints(display width, label etc.) for a View Object(and Entity Object) on the fly from an external system. Let me share a simple possible solution for this specific use case.

A glance at the implementation

The idea is to override ViewRowImpl::createViewRowAttrHints(AttributeDefImpl attrDef) to return a custom implementation of ViewRowAttrHintsImpl class. The same concept has been discussed in one of my previous post sometime back - Decorate UI with view row Attribute's User Interface hints. Please note that, this is the place( custom ViewRowAttrHintsImpl class - LazyViewRowAttrHintsImpl) where we are adding the hook to retrieve the Attribute Hints from third party service.

@Override
protected ViewRowAttrHintsImpl createViewRowAttrHints(AttributeDefImpl attrDef) {
  return new LazyViewRowAttrHintsImpl(attrDef, this);
}

The constructor of LazyViewRowAttrHintsImpl may look like as shown in the following code snippet. Please take a look at th source of LazyViewRowAttrHintsImpl.java to get a feel of the implementation (work space is attached at the end of this post).

 public class LazyViewRowAttrHintsImpl 
                     extends ViewRowAttrHintsImpl {
  
  public LazyViewRowAttrHintsImpl(
           AttributeDefImpl attributeDefImpl,
           ViewRowImpl viewRowImpl) {
    super(attributeDefImpl, viewRowImpl);

    //The following call retrieves AttrHints 
    //from third party service
    //and add the same to Attribute Defn of VO
    decorateWithLazyHints(attributeDefImpl);
  } ...

You can download the sample workspace from here.
[Runs with Oracle JDeveloper 11g R1 PS3 + HR Schema]

How to run this sample?

Please run the dept.jspx. You may notice that default UI hints ( such as label, field width etc. ) are overridden with values from a dummy service( UIHintsService ).