The new ComponentPropertyModel

[Johan Compagner]

That one really doesn't work if i understand correctly what it should do

i guess it should do this:

Form form = new Form(new CompoundModel(new Person))l
form.add(new TextField(new ComponentPropertyModel("name")))

and then it should get name of the person of the compound?

that really doesn't work with the current implementation.
And it will never work in the current setup Because how do you get from the
textfields.setModel (that sets the componentpropertymodel)
to the forms model where the data is in? This can only be done with some
kind of hack
currently this is the code:

AssignmentWrapper(final Component component, final String propertyName)

       /**
        * @see wicket.model.INestedModelContainer#getNestedModel()
        */
       public IModel getNestedModel()
       {
           return component.getModel();
       }

And this piece of code is really wrong. the getNestedModel should return the
parent model of the current model
and that is not the component.getModel() because that is the
assigmentwrapper it self!

then
       public Object getObject()
       {
           return PropertyResolver.getValue(propertyName,
component.getInnermostModel()
                   .getObject());
       }


component.getInnermodelModel() will throw an exception:

IModel nested = model;
       while (nested != null && nested instanceof INestedModelContainer)
       {
           final IModel next =
((INestedModelContainer)nested).getNestedModel();
           if (nested == next)
           {
               throw new WicketRuntimeException("Model for " + nested + "
is self-referential");



because the first nested model == AssigmentWrapper which does getNestedModel
which does component.getModel() which is again assigmentwrapper

what you really want is this:

public Object getObject()
       {
           return PropertyResolver.getValue(propertyName,
component.getParent().getModel().getObject());
       }


so by pass the component and go straight to its parent

so AssignmentWrapper will be then this:

static private class AssignmentWrapper extends AbstractReadOnlyModel
           implements
               INestedModelContainer
   {
       private static final long serialVersionUID = 1L;

       private final Component component;

       private final String propertyName;

       AssignmentWrapper(final Component component, final String
propertyName)
       {
           this.component = component;
           this.propertyName = propertyName;
       }

       /**
        * @see wicket.model.INestedModelContainer#getNestedModel()
        */
       public IModel getNestedModel()
       {
           return ComponentPropertyModel.this;
       }

       protected String propertyExpression()
       {
           return propertyName;
       }

       public Object getObject()
       {
           return PropertyResolver.getValue(propertyName,
component.getParent().getModel().getObject());
       }
   }

then it should work.

But why do we need this model? this doesn't really save anything or add
anything
you still have to do this:

Form form = new Form(new CompoundModel(new Person))l
form.add(new TextField("couldntbename",new ComponentPropertyModel("name")))

so thats almost as much as:


Model model = new Model(new Person);
Form form = new Form(model);
form.add(new TextField("couldntbename",new PropertyModel("name",model)))

and it is more or less tries to replace the BoundCompoundPropertyModel:


BoundCompoundPropertyModel model = new BoundCompoundPropertyModel(new
Person);
Form form = new Form(model);
form.add(model.bind(new TextField("couldntbename"),"name"));

So we better tweak BoundCompoundPropertyModel:

BoundCompoundPropertyModel model = new BoundCompoundPropertyModel(new
Person);
Form form = new Form(model);
form.add(new TextField("couldntbename",model.bind("name")));

so add (or change) the bind method that it just gets a string property and
returns the model (which is a wrapper around the component and the property
name)

thats much neater


johan