31.2. Annotations

Seam also provides annotations to let you use Seam components as JSF converters and validators:
@Converter 
@Name("itemConverter") 
@BypassInterceptors 
@Converter 
public class ItemConverter implements Converter { 
  @Transactional 
  public Object getAsObject(FacesContext context, UIComponent cmp, 
                            String value) { 
    EntityManager entityManager = 
      (EntityManager) Component.getInstance("entityManager"); 
    entityManager.joinTransaction(); // Do the conversion 
  } 
  public String getAsString(FacesContext context, UIComponent cmp, 
                            Object value) { 
    // Do the conversion 
  } 
}
<h:inputText value="#{shop.item}" converter="itemConverter" />
Registers the Seam component as a JSF converter. Here, the converter accesses the JPA EntityManager inside a JTA transaction when converting the value back to its object representation.
@Validator 
@Name("itemValidator") 
@BypassInterceptors 
@org.jboss.seam.annotations.faces.Validator 
public class ItemValidator implements javax.faces.validator.Validator { 
  public void validate(FacesContext context, UIComponent cmp, 
                       Object value) throws ValidatorException { 
    ItemController ItemController = 
      (ItemController) Component.getInstance("itemController"); 
    boolean valid = itemController.validate(value); 
    if (!valid) { 
      throw ValidatorException("Invalid value " + value); 
    } 
  } 
}
<h:inputText value="#{shop.item}" validator="itemValidator" />
Registers the Seam component as a JSF validator. Here, the validator injects another Seam component; the injected component is used to validate the value.