Question

I’m using a CompoundPropertyModel (via PropertyListView) to print properties of an object (User).

One of the properties of the User object is a boolean. I would like the boolean to be rendered using a custom conversion (false -> “disabled”, true -> “enabled”).

How can I achieve this without adding new method to the User object?

add(new PropertyListView<User>("users", new LoadableUsersModel()) {
    @Override
    protected void populateItem(ListItem<User> item) {
        item.add(new Label("firstname"));
        item.add(new Label("surname"));
        item.add(new Label("username"));
        item.add(new Label("email"));
        item.add(new Label("active"));
    }
});

Answer 1

There are several ways to achieve this:

• Get your Model Object from item, and use an if-else.

  User user = item.getModelObject();
  item.add(new Label("active", user.isActive() ? "enabled" : "disabled"));

• Implement an IConverter and return the desired value in its convertToString() method. Return an instance of the converter in an override of the getConverter() method of the Label. In this example it’s all anonymous classes, it’d be better to define them as independent classes, at least the converter, and have a static method to use just a single instance.

  item.add(new Label("active"){
      public IConverter getConverter(Class type){
          return new IConverter(){
              public String convertToString(Object value, Locale locale){
                  if (Boolean.TRUE.equals(value) { return "enabled"; }
                  else if (Boolean.FALSE.equals(value) { return "disabled"; }
                  else { return null; }
              }
              public Object convertToObject(String value, Locale locale){
                  // Not needed, only used by FormComponents
                  return null;
              }
           }
      }
  };

• Use an AbstractReadOnlyModel to return the desired value, feeding it with the active property, or a Model with it:

  PropertyModel pm = new PropertyModel(item.getModel(), "active");
  item.add(new Label("active", new AbstractReadOnlyModel(){
      public Object getObject() { 
          if (Boolean.TRUE.equals(pm.getObject()) { return "enabled"; }
          else if (Boolean.FALSE.equals(pm.getObject()) { return "disabled"; }
          else { return null; }
      }
  }));

As a side note, if enabled and disabled are literals that are to be shown in the page, you might be interested in localizing them in a xml resource file, and use getString() instead.