[google-appengine] operating on too many entity groups in a single transaction.
Hello Group,
I have googled for this error and as far as I can see, the Appengine
Datastore does not support more than 5 Groups in a transaction (at least in
a XG Transaction).
OK ... but how do I get the the following issue done:
*1. I am using OpenSeccionInView Pattern. See my code below:*
@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);//==(1) Create EM
em.getTransaction().begin();//==(2) Begin Transaction
try {
chain.doFilter(request, response);
em.getTransaction().commit();//==(3) Commit Transaction
} catch (ConstraintViolationException cve) {
//This exception is thrown on Constraint Violation JSR303
if(em.getTransaction().isActive()) {
//This is usually never called
em.getTransaction().rollback();
}
} catch (Exception e) {
if(em.getTransaction().isActive()) {
em.getTransaction().rollback();
}
e.printStackTrace();
} finally {
if(em.isOpen()) {
em.close();//==(4) Close EM
}
}
}
*2. I have Entities called JobCategory that stays in OneToMany relation
with itself and OneToMany Relation with Job Entity
(JPA is used with DataNucleus)
*@Entity
public class JobCategory {
@OneToMany(mappedBy = "mainCategory", cascade = CascadeType.ALL)
@OrderBy("i18nKey ASC")
private List subCategories = new ArrayList();
@ManyToOne
private JobCategory mainCategory;
@OneToMany(mappedBy = "jobCategory")
@OrderBy("creationDate DESC")
private List jobs = new ArrayList();
...
/**
* Method will return All JobCategories that are available in the
database
*/
public static List findAllJobCategories() {
EntityManager em = ThreadLocalEntityManager.get();
Query query = em.createQuery("SELECT e FROM " +
JobCategory.class.getSimpleName() + " e ORDER BY e.i18nKey");
return (List) query.getResultList();
}
...
}
*My Question:*
I woudl like to load all JobCategories (there are more than 10 main
JobCategories with 5-6 Subcategories each), but as mentioned the DB does
not support more than 5 Groups per transaction.
The OSIV-Pattern, as shown in my code above and explained here:
https://community.jboss.org/wiki/OpenSessionInView?_sscc=t ... opens one
transaction for every DB-call which lets me get max 5 Grouped-Entities!?
How do I get *all JobCategories* loaded properly!?
I assume that there is something wrong with my OSIV-Pattern since it allows
only one transaction per call. But this is exactly what the JBOSS example
did!?
Thank you in advance for your help!!
Nermin
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[google-appengine] Re: JPA @PrePersist does not work on a child :(
I fixed it.
the solution is explained on my previous post:
https://groups.google.com/forum/?hl=de&fromgroups#!topic/google-web-toolkit/p9p4_r2Gv4U
Best regards:
Nermin
Am Dienstag, 4. Juni 2013 16:24:32 UTC+2 schrieb nermin@gmail.com:
>
> Hello Group,
>
> I have a "probably simple" problem with my application which I am
> obviously not able to solve.
>
> Two Classes: CompanyX, TradesmanX
> CompanyX stays in a OneToOne Connection with TradesmanX
>
> I use @PrePersist on Tradesman in order to pre-set some fields (e.g. Has
> password or set Account creation date) before the Object gets persisted in
> the DB.
>
> My code is available here:
> https://dl.dropboxusercontent.com/u/2983671/JPA_Problem/JPA_Problem.zip
>
> @Entity
> public class CompanyX {
> ...
> @OneToOne(cascade=CascadeType.ALL)
> private TradesmanX adminUser;
> }
>
>
> @Entity
> public class TradesmanX {
> ...
> @PrePersist
> public void myMethod(){
> System.out.println("Pre Persist");
> this.setFirstName("USER_X");
> }
> ...
> }
>
> //Here is how I persist them within my test servlet:
>
> private void testPersistenceTwo() {
>
> CompanyX company = new CompanyX();
> company.setName("my Comp");
>
> TradesmanX user = new TradesmanX();
> user.setFirstName("Test_FName");
> user.setLastName("Test_Lname");
>
> company.setAdminUser(user);
> company.persist();
> }
>
>
> The ERROR l am facing looks like follows:
>
> javax.persistence.PersistenceException: Detected attempt to establish
> CompanyX(no-id-yet) as the parent of TradesmanX(7) but the entity
> identified by TradesmanX(7) has already been persisted without a parent. A
> parent cannot be established or changed once an object has been persisted.
> at
> org.datanucleus.api.jpa.NucleusJPAHelper.getJPAExceptionForNucleusException(NucleusJPAHelper.java:302)
> at
> org.datanucleus.api.jpa.JPAEntityManager.close(JPAEntityManager.java:197)
> at com.emajstor.server.persistence.CompanyX.persist(CompanyX.java:42)
> at
> com.emajstor.server.test.MyTestServlet.testPersistenceTwo(MyTestServlet.java:88)
> at com.emajstor.server.test.MyTestServlet.doGet(MyTestServlet.java:41)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
> at
> org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
> at
> com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
> at
> com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:123)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
> at
> com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
> at
> com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
> at
> com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
> at
> com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
> at
> com.google.appengine.tools.development.DevAppServerServersFilter.doDirectRequest(DevAppServerServersFilter.java:369)
> at
> com.google.appengine.tools.development.DevAppServerServersFilter.doDirectServerRequest(DevAppServerServersFilter.java:352)
> at
> com.google.appengine.tools.development.DevAppServerServersFilter.doFilter(DevAppServerServersFilter.java:115)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
> at
> org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
> at
> org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
> at
> org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
> at
> org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
> at
> org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
> at
> com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:97)
> at
> org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
> at
> com.google.appengine.tools.develop
[google-appengine] JPA @PrePersist does not work on a child :(
Hello Group,
I have a "probably simple" problem with my application which I am obviously
not able to solve.
Two Classes: CompanyX, TradesmanX
CompanyX stays in a OneToOne Connection with TradesmanX
I use @PrePersist on Tradesman in order to pre-set some fields (e.g. Has
password or set Account creation date) before the Object gets persisted in
the DB.
My code is available here:
https://dl.dropboxusercontent.com/u/2983671/JPA_Problem/JPA_Problem.zip
@Entity
public class CompanyX {
...
@OneToOne(cascade=CascadeType.ALL)
private TradesmanX adminUser;
}
@Entity
public class TradesmanX {
...
@PrePersist
public void myMethod(){
System.out.println("Pre Persist");
this.setFirstName("USER_X");
}
...
}
//Here is how I persist them within my test servlet:
private void testPersistenceTwo() {
CompanyX company = new CompanyX();
company.setName("my Comp");
TradesmanX user = new TradesmanX();
user.setFirstName("Test_FName");
user.setLastName("Test_Lname");
company.setAdminUser(user);
company.persist();
}
The ERROR l am facing looks like follows:
javax.persistence.PersistenceException: Detected attempt to establish
CompanyX(no-id-yet) as the parent of TradesmanX(7) but the entity
identified by TradesmanX(7) has already been persisted without a parent. A
parent cannot be established or changed once an object has been persisted.
at
org.datanucleus.api.jpa.NucleusJPAHelper.getJPAExceptionForNucleusException(NucleusJPAHelper.java:302)
at
org.datanucleus.api.jpa.JPAEntityManager.close(JPAEntityManager.java:197)
at com.emajstor.server.persistence.CompanyX.persist(CompanyX.java:42)
at
com.emajstor.server.test.MyTestServlet.testPersistenceTwo(MyTestServlet.java:88)
at com.emajstor.server.test.MyTestServlet.doGet(MyTestServlet.java:41)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at
org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at
com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:123)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.DevAppServerServersFilter.doDirectRequest(DevAppServerServersFilter.java:369)
at
com.google.appengine.tools.development.DevAppServerServersFilter.doDirectServerRequest(DevAppServerServersFilter.java:352)
at
com.google.appengine.tools.development.DevAppServerServersFilter.doFilter(DevAppServerServersFilter.java:115)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at
org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at
org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at
org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at
com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:97)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at
com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:438)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at
org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at
org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at
