Primefaces p:autcomplete issues with String field in POJO

Question

I am building a JSF form which includes a primefaces p:autoComplete component. The following is an extract from my xhtml page, showing the relvant information about the autoComplete component.

<p:autoComplete 
    value="#{curAttribute.value}" 
    completeMethod="#{newBacking.lookupActivated}"
    var="curEntry" 
    itemLabel="#{curEntry.classname}" 
    itemValue="#{curEntry.id}"
    emptyMessage="Start typing..."/>

Please notice that curAttribute is an instance of the CosmoAttribute class, and that the CosmoAttribute.value is a String (of course, CosmoAttribute has all the getters and setters for its fields).

The method newBacking.lookupActivated() returns a List<CosmoCard>.

CosmoCard.classname and CosmoCard.id are both Strings.

I know that I'm woirking with POJOs, but since all my values are String fields from a POJO, I don't think that I need a converter. Anyway, my autoComplete field works fine, but when i select an item, i get the following exception:

SEVERE:   Error Rendering View[/test.xhtml]
javax.el.PropertyNotFoundException: /test.xhtml @98,68 itemLabel="#{curEntry.id}": The class 'java.lang.String' does not have the property 'id'.
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:111)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
    at org.primefaces.component.autocomplete.AutoComplete.getItemLabel(AutoComplete.java:148)
    .
    .

Caused by: javax.el.PropertyNotFoundException: The class 'java.lang.String' does not have the property 'id'.
    at javax.el.BeanELResolver.getBeanProperty(BeanELResolver.java:730)
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:351)
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    .
    .

Has anyone a clue of what am I doing wrong? You can find a very similar question here, but it was unfortunately unanswered. I am willing to provide more details about my code.

UPDATE:

Actually, everything is working fine: I see the correct value in the dropdown of the p:autocomplete. As i select a value, the data in the backing bean (newBacking) is updated accordingly. I just can't get rid of the exception, which, however, does not have any effect on the execution of my page.

I am respecting the constraints of the tag, i.e. the value attribute and the itemValue are of the same type (both Strings). The only thing that is not properly ok is that the system tries to convert a List in a List, I don't know why, or when, but the failure in the conversion (and the subsequent exception) does not have any effect on the behaviour of my page.

UPDATE:

Here is the link to a very simplified version of the project (netbeans). The relevant files of the project are also listed below.

test.xhtml

<h:body>
    <h:form id="form">  
        <p:dataTable var="curAttribute" value="#{newBacking.card.attributes}">
            <p:column >
                THE CURSED FIELD <br /><br />

                <p:autoComplete 
                    value="#{curAttribute.value}" 
                    completeMethod="#{newBacking.lookupActivated}"
                    var="curEntry" 
                    itemLabel="#{curEntry.code}" 
                    itemValue="#{curEntry.id}">
                </p:autoComplete>
            </p:column>
        </p:dataTable> 
    </h:form>    

newBacking.java

@Named()
@SessionScoped
public class NewBacking implements Serializable {

   private CosmoCard card;

   private String currentCardClassname = "";

   @PostConstruct
   public void init() {

       Random randomGenerator = new Random();
       card = new CosmoCard();
       card.setId("ID" + randomGenerator.nextInt(1000));

       CosmoAttribute myLA = new CosmoAttribute();
       myLA.setLabel("LookupAttributeLabel");
       myLA.setValue("LookupAttributeValue");
       card.getAttributes().add(myLA);
   }

   public CosmoCard getCard() {
      return card;
   }

   public String getCurrentCardClassname() {
      return currentCardClassname;
   }

   public void setCurrentCardClassname(String currentCardClassname) {
       this.currentCardClassname = currentCardClassname;
   }

   public List<CosmoCard> lookupActivated(String tgtQuery) {

       Logger.getLogger(NewBacking.class.getName()).info("[NewBacking.lookupActivated()] Query: " + tgtQuery);
       return CosmoCardList.generateCardList(10).getCards();
   }

}

Answer 1

Your complete method is returning an instance of a complex class and thereby you need a converter. Without the existense of a converter, your component is thinking that its working with a string and trying to give reference to it when getting value and label attributes. Try using this and see if it works but I strongly recommend creating your own converter based on your needs:

@FacesConverter("anySelectConverter")
public class AnySelectConverter implements Converter{


     private static Map<Object, String> entities = new ConcurrentHashMap<Object, String>();

        @Override
        public String getAsString(FacesContext context, UIComponent component, Object entity) {

            // TODO : Fix
            if(entity == null)
                return "";

            synchronized (entities) {
                if (!entities.containsKey(entity)) {
                    String uuid = UUID.randomUUID().toString();
                    entities.put(entity, uuid);
                    return uuid;
                } else {
                    return entities.get(entity);
                }
            }
        }

        @Override
        public Object getAsObject(FacesContext context, UIComponent component, String uuid) {
            for (Entry<Object, String> entry : entities.entrySet()) {
                if (entry.getValue().equals(uuid)) {
                    return entry.getKey();
                }
            }
            return null;
        }

    }