Can Converter @FacesConverter(forClass=[someClass.class]) be implemented as @Singleton @Lock(READ)?

Question

The answer is YES, with a little help from JNDI lookup.

I just removed the CustomerControllerConverter from the JSF @RequestScoped CustomerController, created the converter class, marked it with @Singleton @Lock(READ), and referenced the @Stateless EJB via JNDI lookup. See below.

package converter;

import java.util.concurrent.TimeUnit;

import javax.ejb.AccessTimeout;
import javax.ejb.Lock;
import javax.ejb.LockType;
import javax.ejb.Singleton;

import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.FacesConverter;

import javax.naming.InitialContext;

import jpa.entities.Customer;
import jpa.session.CustomerFacade;


/**
 *
 * @author Administrator
 */
@Singleton
@Lock(LockType.READ)
@AccessTimeout(value = 1, unit = TimeUnit.MINUTES)
@FacesConverter(forClass = Customer.class)
public class CustomerConverter implements Converter {

    public CustomerConverter() {

    }

    public Object getAsObject(FacesContext facesContext, UIComponent component, String value) {
        if (value == null || value.length() == 0) {
            return null;
        }
        /*
         * 2012-07-10 when user enters invalid/incomplete value (e.g. "irene", see below) in AutoComplete
         *
        WARNING: For input string: "irene"
        java.lang.NumberFormatException: For input string: "irene"
                at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
                at java.lang.Integer.parseInt(Integer.java:492)
                at java.lang.Integer.valueOf(Integer.java:582)
                ...
                ...
                at org.primefaces.component.autocomplete.AutoCompleteRenderer.getConvertedValue(AutoCompleteRenderer.java:529)
                at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1030)
                at javax.faces.component.UIInput.validate(UIInput.java:960)
         *
         */
        try {
            Integer test = getKey(value);
        } catch (java.lang.NumberFormatException e) {
            return null;
        }
        Object object = null;
        CustomerFacade ejbFacade;
        try {
            InitialContext ic = new InitialContext();
            ejbFacade = (CustomerFacade) ic.lookup("java:global/appWARFileNameOrAppContextName/CustomerFacade");
            if (ejbFacade == null) {
                System.err.println("CustomerConverter.getAsObject(): ejbFacade = null)");
                return null;
            }
        } catch (Exception e) {
            System.err.println("CustomerConverter.getAsObject(): error on JNDI lookup of CustomerFacade");
            e.printStackTrace();
            return null;
        }
        try {
            object = ejbFacade.find(getKey(value));
        } catch (Exception e) {
            System.err.println("CustomerConverter.getAsObject(): error on ejbFacade.find(getKey(value))");
            e.printStackTrace();
            return null;
        }
        return object;
    }

    java.lang.Integer getKey(String value) {
        java.lang.Integer key;
        key = Integer.valueOf(value);
        return key;
    }

    String getStringKey(java.lang.Integer value) {
        StringBuffer sb = new StringBuffer();
        sb.append(value);
        return sb.toString();
    }

    public String getAsString(FacesContext facesContext, UIComponent component, Object object) {
        if (object == null) {
            return null;
        }
        if (object instanceof Customer) {
            Customer o = (Customer) object;
            return getStringKey(o.getCustomerId());
        } else {
            throw new IllegalArgumentException("object " + object + " is of type " + object.getClass().getName() + "; expected type: " + Customer.class.getName());
        }
    }
}

LESSON LEARNED: ejbFacade could NOT be referenced or instantiated via the following:

@Inject, @EJB, BeanManager

References:

Oracle blogs

TomEE JavaEE Examples - Referencing EJBs

Ultimately, I had to refer to the server.log file of Glassfish, the Reference Implementation (RI), to see a sample of JNDI lookup path for my @Stateless EJB's, since I used Glassfish, in the past. :)

UPDATE:

You can also find the portable global JNDI name in TomEE/catalina log. It will look like this, below.

Apr 13, 2013 10:00:58 AM org.apache.openejb.assembler.classic.JndiBuilder bind
INFO: Jndi(name=CustomerFacadeLocalBean) --> Ejb(deployment-id=CustomerFacade)

Apr 13, 2013 10:00:58 AM org.apache.openejb.assembler.classic.JndiBuilder bind
INFO: Jndi(name=global/webApp/CustomerFacade!jpa.session.CustomerFacade) --> Ejb(deployment-id=CustomerFacade)

Apr 13, 2013 10:00:58 AM org.apache.openejb.assembler.classic.JndiBuilder bind
INFO: Jndi(name=global/webApp/CustomerFacade) --> Ejb(deployment-id=CustomerFacade)

where 'webApp' in the global JNDI name may be the name of your WAR filename or possibly EJB JAR filename, etc...

Hope this helps others!