Re: RequestFactory, ValueProxy, EntityProxy and JSR303 - is it a bug?

Thomas,

thank you for your time and your Help. I will now migrate my application to Objectitfy.

I am sick of JPA and Datanucleus and I am not willing to continue jumping from one JPA problem into another. I hope Objectify will save me from this struggling with Datastore.

Many Many thanks for your help!

Nermin

On Tuesday, October 22, 2013 6:26:37 PM UTC+2, Thomas Broyer wrote:

On Tuesday, October 22, 2013 6:12:36 PM UTC+2, Nermin wrote:

OK Thomas, I will go for Objectify.

The only problem is that I cannot find a really good tutorial for using it with Requestfactory.

http://code.google.com/p/objectify-appengine/wiki/ObjectifyWithGWT
For example, their official GWT-Tutorial is totally confusing (see link above), they state: "Make sure your entity classes are part of your GWT module (typically in a .client package)." ...... Now I get totally confused! Is this really true?????

They use GWT-RPC, so yes (your entities would be used on the client-side, so they'd have to be in .client or .shared – assuming you follow GWT's naming conventions here).

It's not the case when you use RequestFactory.

Have you looked at http://turbomanage.wordpress.com/2011/03/25/using-gwt-requestfactory-with-objectify/ ? (linked at the bottom of the above-linked page)

(from memory, it's a bit old, back in the days when Objectify didn't have a request-scoped cache, so it could break depending on the requests you made; but Objectify now has a request-scoped cache, so it should Just Work™; just beware of this: https://code.google.com/p/objectify-appengine/wiki/Caching#Transactions_and_the_Session_Cache, but if I understand correctly there are relatively few cases where it would break with RequestFactory).

I have played today wit it a bit with Objectify, and I have managed it to create an simple working example.
Can you please tell me if this is the right way of working with the Objectify 4 and the RequestFactory?

Heh, I never used Objectify either (I never worked with AppEngine), but I'll do my best.

 

The code works but I am somehow not really sure if I am on the right track. Here is my code:
Btw: I have all my entities on server side.

@Entity
public class EntityOne {
    @Id
    private Long id;
    private Integer version = 0;
    private String name;   
    private Key<EntityTwo> entityTwoKey;    //This is the Key for the EntityTwo (Using this you will know how to lad it)
    @Ignore
    private EntityTwo entityTwo; //Transient field (not saved in the Datastore) it is a real representation of the entityt
   
    @OnSave
    void onPersist() {
        version++; // Increase the Version
    }

    // ========= HANDLER METHODS ==========//
    public static EntityOne findEntityOne(Long id) {
        return ofy().load().type(EntityOne.class).id(id).now();
    }

    public void persist() {
        ofy().save().entity(this).now();
    }
   
....
    public Key<EntityTwo> getEntityTwoKey() {
        return entityTwoKey;
    }
    public void setEntityTwoKey(Key<EntityTwo> entityTwoKey) {
        this.entityTwoKey = entityTwoKey;
    }

    public EntityTwo getEntityTwo() {
        //Load entity using its Key
        this.entityTwo = ofy().load().key(getEntityTwoKey()).now();
        return this.entityTwo;
    }
    public void setEntityTwo(EntityTwo entityTwo) {
        //Step1: Set the key (This will make sure it be saved into the DB)
        this.entityTwoKey = Key.create(EntityTwo.class, entityTwo.getId());
        //Step2: Set entity
        this.entityTwo = entityTwo;
    }
}


@Entity
public class EntityTwo {
    @Id
    private Long id;
    private Integer version = 0;

    private String name;
   
   @OnSave
    void onPersist() {
        version++; // Increase the Version
    }
   
    // ========= HANDLER METHODS ==========//
    public static EntityTwo findEntityTwo(Long id) {
        return ofy().load().type(EntityTwo.class).id(id).now();
    }
   
    public EntityTwo persist() {
        ofy().save().entity(this).now();
        return this;
    }
... Get/set
}

@ProxyFor(EntityOne.class)
public interface EntityOneProxy extends EntityProxy {
    Long getId();
    Integer getVersion();
    void setVersion(Integer version);

Do you really want to get/set the version on the client-side? (OK, get the version maybe, but set it?)

 

    String getName();
    void setName(String name);

    EntityTwoProxy getEntityTwo();
    void setEntityTwo(EntityTwoProxy entityTwo);
}

@ProxyFor(EntityTwo.class)
public interface EntityTwoProxy extends EntityProxy {
    Long getId();
    Integer getVersion();
    void setVersion(Integer version);
    String getName();
    void setName(String name);
}

... And registering to my RequestFactory interface ... etc.

Is this code OK??

It looks OK to me.

 

If I understood correctly, I do not need to care about OSIV etc.

Yes, except https://code.google.com/p/objectify-appengine/wiki/Caching#Transactions_and_the_Session_Cache as already mentioned.

 

All I need to do is to register ObjectifyFilter. Right?

It seems so. 

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