Writing a custom converter which wraps EntityConverter

[newlukai]

Hi,

I can't find any hint about this issue: I want to write a custom converter which wraps Seam's EntityConverter.

I've a drop-down list which should display several entities. Additionally it should contain some "custom entities" which describe a set of the real entities. Image these entities were priorities from 1 to 7. The custom entities should provide values "priorities < 3" and "priorities > 3". Those custom entities aren't persisted in the database so the EntityConverter isn't applicable here.

I had the idea to write a custom converter which delegates the noSelectionLabel and the real entities to EntityConverter and handles the custom entities itself.

But I can't find a document or somewhat that describes how I can do this. Could anyone help me?

Thanks in advance
Newlukai

[newlukai]

Isn't there anyone who's done such an implementation?

[pmuir]

This should be fairly straightforward - just extend the class, copy the annotations (and give it a new name), and delegate as needed.

[newlukai]

Thanks. I've it implemented this way:

public class SeverityConverter implements Converter {
 public Object getAsObject(FacesContext context, UIComponent component, String value) throws ConverterException {
 Converter entityConverter = (Converter) Component.getInstance("org.jboss.seam.ui.entityConverter");

 if(NoSelectionConverter.NO_SELECTION_VALUE.equals(value)) {
 return entityConverter.getAsObject(context, component, value);
 }

 int severity = Integer.parseInt(value);
 if(severity >= 0) {
 return entityConverter.getAsObject(context, component, value);
 }

 return AdditionalSeverities.getSeverityByID(severity);
 }

 public String getAsString(FacesContext context, UIComponent component, Object value) throws ConverterException {
 Converter entityConverter = (Converter) Component.getInstance("org.jboss.seam.ui.entityConverter");
 Severityclass severity = (Severityclass) value;

 if(severity == null || severity.getID() >= 0) {
 return entityConverter.getAsString(context, component, value);
 }

 return String.valueOf(severity.getID());
 }
}

I'm wondering if the way I get the EntityConverter is OK or if there's a more elegant way.

[pmuir]

Yes, thats fine :)

[newlukai]

Thanks. Have a nice weekend.