GAE JDO persistencemanager GetObjectById returns No such object?

Question

I've been trying to get my GAE code running. I have problem retrieving Users with encodedKey:

I have this User Data Manager class that manage all my CRUD transactions using singleton PMF.

I have Users, using encoded String as my key:

public class Users implements Serializable {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName = "datanucleus", key = "gae.encoded-pk", value = "true")
private String encodedKey;
@Persistent
@Extension(vendorName = "datanucleus", key = "gae.pk-id", value = "true")
private Long keyId;
 --- code continues ----

I have this createUser method in DM class

public static void createUser(Users user) {
    PersistenceManager pm = PMF.get().getPersistenceManager();
    try {
        Key key = KeyFactory.createKey(Users.class.getSimpleName(),
                user.getEmail());
        user.setEncodedKey(KeyFactory.keyToString(key));
        pm.makePersistent(user);
    } catch (Exception e) {
        logger.log(Level.SEVERE, e.toString());
    } finally {
        pm.close();
    }
}

And the problem is with this piece of code to retrieve:

    public static Users retrieveUser(String encodedKey) {
    PersistenceManager pm = PMF.get().getPersistenceManager();
    Users user = null;
    try {
//          Key key = KeyFactory.createKey(Users.class.getSimpleName(),
//                  user.getEmail());
// I tried recreating the key with user's email, but it does not work either            
        pm.getObjectById(KeyFactory.stringToKey(encodedKey));
    } catch (Exception e) {
        logger.severe(e.toString());
    } finally {
        pm.close();
    }
    return user;
}

It is giving me the following error:

 SEVERE: javax.jdo.JDOObjectNotFoundException: No such object
 FailedObject:Users("t")
 NestedThrowables:org.datanucleus.exceptions.NucleusObjectNotFoundException: No such object

"t" is the dummy user's email, anyway.

How do I use the encodedKey to get the entity using PMF? Currently, I am resorting to identifying using email and query, but getting object by key should work.

Edits:

I made the following changes to my model object:

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName = "datanucleus", key = "gae.encoded-pk", value = "true")
private String encodedKey;
@Persistent
@Extension(vendorName="datanucleus", key="gae.pk-name", value="true")
private String keyName;

Based on this and google's documentation:

The app can populate this value prior to saving using a key with a name, or it can leave it null. If the encoded key field is null, the field is populated with a system-generated key when the object is saved.

I thought that simply persisting this would work:

public static void createUser(Users user) {
    PersistenceManager pm = PMF.get().getPersistenceManager();
    try {
        user.setKeyName(user.getEmail()); 
        pm.makePersistent(user);
    } catch (Exception e) {
        logger.log(Level.SEVERE, e.toString());
    } finally {
        pm.close();
    }
}

But, no such luck, it throws me this error whether or not I set the keyname first:

SEVERE: javax.jdo.JDOFatalUserException: Invalid primary key for entity.Users.  Cannot have a null primary key field if the field is unencoded and of type String.  Please provide a value or, if you want the datastore to generate an id on your behalf, change the type of the field to Long.
NestedThrowables:
org.datanucleus.exceptions.NucleusFatalUserException: Invalid primary key for entity.Users.  Cannot have a null primary key field if the field is unencoded and of type String.  Please provide a value or, if you want the datastore to generate an id on your behalf, change the type of the field to Long.

I don't get it, why is it not generating a new key for my new entity? I'm thinking of going back to Key due to all these problems. I thought encodedKey will be more portable because I'm using the GAE server to serve data to my Android client.

Answer 1

What's the point in calling setEncodedKey() when you marked that field to have its value generated? (with the valueStrategy=IDENTITY). If something is generated (when inserted in the DB, like that is), then your value passed in to setEncodedKey is ignored, as clearly seen by calling pm.getObjectId(obj).