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?????
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? 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);
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??
If I understood correctly, I do not need to care about OSIV etc.
All I need to do is to register ObjectifyFilter. Right?
Thank you in advance for your help:
Nermin
On Tuesday, October 22, 2013 3:12:59 PM UTC+2, Thomas Broyer wrote:
-- 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?????
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? 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);
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??
If I understood correctly, I do not need to care about OSIV etc.
All I need to do is to register ObjectifyFilter. Right?
Thank you in advance for your help:
Nermin
On Tuesday, October 22, 2013 3:12:59 PM UTC+2, Thomas Broyer wrote:
On Tuesday, October 22, 2013 2:03:19 PM UTC+2, Nermin wrote:
On Tuesday, October 22, 2013 11:40:48 AM UTC+2, Thomas Broyer wrote:
On Monday, October 21, 2013 11:11:07 PM UTC+2, Nermin wrote:Dear Thomas,
thank you for your Post. I have checked my OSIV konfiguration and I have it the right way (transaction per service method).Apparently not (see below)
OK, let me show you my OSIV code:
=========== THREAD LOCAL EM
public class ThreadLocalEntityManager {
private static ThreadLocal<EntityManager> holder = new ThreadLocal<EntityManager>();
private ThreadLocalEntityManager() {
}
public static EntityManager get() {
return holder.get();
}
public static void set(EntityManager em) {
holder.set(em);
}
}
=========== FILTER
public class AppHandlerFilter implements Filter {
....
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
//1. Create new EntityManager for this call
EntityManager em = factory.createEntityManager();
ThreadLocalEntityManager.set(em); //== Create EM
try {
chain.doFilter(request, response);
} catch (Exception e) { //Any other Exception
if(em.getTransaction().isActive()) {
em.getTransaction().rollback();
}
logger.severe(e.getMessage());
e.printStackTrace();
} finally {
if(em.isOpen()) {
em.close(); //== Close EM
}
}
}
}
======== Entity:
@Entity
public class TestEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@org.datanucleus.api.jpa.annotations.Extension( vendorName = "datanucleus", key = "gae.encoded-pk", value = "true")
private String id;
@Version
private Long version;
@NotNull
private String myName;
@Pattern(regexp = "[^@\\s]+@[^@\\s]+\\.[A-Za-z]{2,4}", message="Invalid e-mail address")
@NotNull
private String myEmailAddress;
public static TestEntity findTestEntity(String id) {
if (id == null) {
return null;
}
TestEntity te = null;
EntityManager em = ThreadLocalEntityManager.get();
em.getTransaction().begin();
te = em.find(TestEntity.class, id);
em.getTransaction().commit();
return te;
}
public ProcessResponse persist() {
EntityManager em = ThreadLocalEntityManager.get();
em.getTransaction().begin();
em.persist(this);
em.refresh(this);
em.getTransaction().commit();
return new ProcessResponse(this.getId(), true);
}
public ProcessResponse update(){
EntityManager em = ThreadLocalEntityManager.get();
em.getTransaction().begin();
em.merge(this);
em.getTransaction().commit();
return new ProcessResponse(true);
}
...
}
==== persistence.xml
<persistence-unit name="emajstor_persistence" transaction-type="RESOURCE_LOCAL">
<provider>org.datanucleus.api.jpa.PersistenceProviderImpl</ provider>
<class>com.emajstor.server.persistence.TestEntity</class>
<exclude-unlisted-classes>true</exclude-unlisted- classes>
<properties>
<property name="datanucleus.NontransactionalRead" value="true"/>
<property name="datanucleus.NontransactionalWrite" value="true"/>
<property name="datanucleus.ConnectionURL" value="appengine"/>
<property name="datanucleus.appengine.datastoreEnableXGTransactions" value="true"/>
<property name="javax.persistence.validation.group.pre-persist" value="javax.validation. groups.Default, com.emajstor.server. persistence.validator. PrePersitValidationGroup" />
<property name="javax.persistence.validation.group.pre-update" value="javax.validation. groups.Default" />
<property name="javax.persistence.validation.group.pre-remove" value="" />
</properties>
</persistence-unit>The debuggung in ReflectiveServiceLayer#validate showed sofar an appropriate behaviour. So it correctly returns ConstraintViolations in all cases?
YES! Validation works fine!
The only problem is that the javax.validation.ConstraintViolationException is turned into a java.lang.RuntimeException in case of an entity update. (see error below.)There shouldn't be any ConstraintViolation*Exception*.
Why shouldn't be there a ConstraintViolation*Exception*?? The entity contains constraint violation because the provided emailAddress is purposely made wrong! But ReflectiveServiceLayer#validate returns a Set<ConstraintViolation> without the need to throw a ConstratintViolation* Exception*. I cannot figure out why is this happening.
I personally find GWT beeing an easy and very elegant tool for web development. The Appengine-Datastore-handling part is in my point of view a real pain in the ass.JPA and JDO are a PITA, whether or not they're used on AppEngine.There are alternatives though (e.g. Objectify).
I agree. Maybe Objectify would be a "better" alternative. Unfortunately I have 12 Entities which I would need to migrate and to test, and there are almost no examples how to use Objectify 4 with the Requestfactory.AFAICT, there's absolutely nothing special; Objectify takes care of the request-scoped caching (required by RequestFactory, the only reason you need OSIV with JPA/JDO).com.google.web.bindery.event.shared.UmbrellaException: Exception caught: Server Error 500 <html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"/>
<title>Error 500 Validation failed for com.emajstor.server.persistence.TestEntity@ 59778fd8 during pre-update for groups [interface javax.validation.groups. Default] - exceptions are attached</title>
</head>
<body><h2>HTTP ERROR 500</h2>
<p>Problem accessing /unAuthRequestFactory. Reason:
<pre> Validation failed for com.emajstor.server.persistence.TestEntity@ 59778fd8 during pre-update for groups [interface javax.validation.groups. Default] - exceptions are attached</pre></p><h3>Caused by:</h3><pre>javax.validation. ConstraintViolationException : Validation failed for com.emajstor.server.persistence.TestEntity@ 59778fd8 during pre-update for groups [interface javax.validation.groups. Default] - exceptions are attached
at org.datanucleus.validation.BeanValidatorHandler.validate( BeanValidatorHandler.java:71)
at org.datanucleus.validation.BeanValidatorHandler.preStore( BeanValidatorHandler.java:86)
at org.datanucleus.api.jpa.JPACallbackHandler.preStore( JPACallbackHandler.java:102)
at org.datanucleus.state.JDOStateManager.flush( JDOStateManager.java:3827)
at org.datanucleus.ObjectManagerImpl. flushInternalWithOrdering( ObjectManagerImpl.java:3888)
at org.datanucleus.ObjectManagerImpl. flushInternal( ObjectManagerImpl.java:3811)
at org.datanucleus.ObjectManagerImpl.flush( ObjectManagerImpl.java:3751)
at org.datanucleus.ObjectManagerImpl.preCommit( ObjectManagerImpl.java:4141)
at org.datanucleus.ObjectManagerImpl. transactionPreCommit( ObjectManagerImpl.java:428)
at org.datanucleus.TransactionImpl. internalPreCommit( TransactionImpl.java:398)
at org.datanucleus.TransactionImpl.commit( TransactionImpl.java:287)
at org.datanucleus.ObjectManagerImpl.close( ObjectManagerImpl.java:1090)
at org.datanucleus.api.jpa.JPAEntityManager.close( JPAEntityManager.java:193)
at com.emajstor.server.AppHandlerFilter.doFilter( AppHandlerFilter.java:91)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain. doFilter(ServletHandler.java: 1157) Your OSIV filter is causing a TransactionImpl.commit, which means there's a transaction spanning the entire request (or maybe you have auto-commit enabled, I don't know how JPA/JDO really work).That commit triggers validation, and the ConstraintViolationException is shadowing the RequestFactory response (which, if ReflectiveServiceLayer#validate behaved expectedly, would be an onConstraintViolations response)
OK .... I see ... YOU ARE RIGHT.
I have tested it using: <property name="datanucleus.NontransactionalWrite" value="false"/> I have expected this to prevent non-transactional write as you mentioned.
I am getting the following error which lets me think that requestfactory is trying to "auto-comit" data into the DB on its own!!RequestFactory is storage-agnostic (everything's handled by user code in locators or findXxx static methods for loading, and in services themselves for everything else)Am I missing some configurations on GWT level??No. There's no configuration on GWT's side. You might want to ask the DataNucleus and/or AppEngine experts how to configure DataNucleus (as I said, I don't know JPA or JDO, they only caused me trouble when I tried to use them, so I can't help you further).
SEVERE: Server error caused by:org.datanucleus.exceptions.NucleusUserException
Cant write fields outside of transactions. You may want to set 'NontransactionalWrite=true'.
org.datanucleus.exceptions.NucleusUserException: Cant write fields outside of transactions. You may want to set 'NontransactionalWrite=true'.
at org.datanucleus.api.jpa.state.PersistentNontransactional. transitionWriteField( PersistentNontransactional. java:170)
at org.datanucleus.state.AbstractStateManager. transitionWriteField( AbstractStateManager.java:871)
at org.datanucleus.state.JDOStateManager.preWriteField( JDOStateManager.java:3575)
at org.datanucleus.state.AbstractStateManager. setStringField( AbstractStateManager.java: 1998)
at com.emajstor.server.persistence.TestEntity. jdoSetmyEmailAddress( TestEntity.java)
at com.emajstor.server.persistence.TestEntity. setMyEmailAddress(TestEntity. java:88) RequestFactory is only calling your setter; it's expected this value will not be persisted until you explicitly persist() the entity.(it might be normal with DataNucleus, but I find it strange that there's mention of JDO here whereas you're using the JPA API)
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