Fetching Data Lazily On A New Page After Hibernate Search

neilac333 · **Joined:** Fri Oct 05, 2007 1:17 pm **Posts:** 78

I am using JPA/Hibernate and Hibernate Search within my Seam application. I have a Widget entity that lazily loads its pricing history. The use case is pretty typical:

* Search for widgets on a form with a set of criteria.
* Display all widget search results from Hibernate Search in a table below the search form. The results include all the items found in the Widget table itself including the widget number, which is a link to another page.
* When you click on the widget number, you come to a widget details page that fetches all the 1:M relationships widgets have with other entities to get information like pricing history. None of these are indexed or have anything to do with Hibernate Search.

Note: Because I am using the RichFaces dataScroller with server-side paging, I have to use my own fancy data model and cannot use the standard Seam annotations like @DataModel and @DataModelSection.

The way I am doing my own version of @DataModelSection is to do the following:

<h:commandLink value="#{widget.number}" action="#{searchAction.setSelectedWidget(widget)}" />

where widget is the iteration variable.

Then through pages.xml, I navigate to the widget details page. All of that works fine until I get this:

Code:

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.myapp.persistence.Widget.pricingHistory, no session or session was closed
   at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:358)
   at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:350)
   at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:97)
   at org.hibernate.collection.PersistentBag.size(PersistentBag.java:225)
   at javax.faces.model.ListDataModel.isRowAvailable(ListDataModel.java:99)
   at javax.faces.model.ListDataModel.setRowIndex(ListDataModel.java:174)
   at javax.faces.model.ListDataModel.setWrappedData(ListDataModel.java:209)
   at javax.faces.model.ListDataModel.<init>(ListDataModel.java:68)
   at org.ajax4jsf.component.SequenceDataAdaptor.getDataModel(SequenceDataAdaptor.java:79)
   at org.ajax4jsf.component.SequenceDataAdaptor.createDataModel(SequenceDataAdaptor.java:64)
   at org.ajax4jsf.component.UIDataAdaptor.getExtendedDataModel(UIDataAdaptor.java:592)
   at org.ajax4jsf.component.UIDataAdaptor.getRowIndex(UIDataAdaptor.java:299)
   at jrockit.reflect.VirtualNativeMethodInvoker.invoke(Ljava.lang.Object;[Ljava.lang.Object;)Ljava.lang.Object;(Unknown Source)
   at java.lang.reflect.Method.invoke(Ljava.lang.Object;[Ljava.lang.Object;I)Ljava.lang.Object;(Unknown Source)
   at com.sun.facelets.util.DevTools.writeAttributes(DevTools.java:240)
   at com.sun.facelets.util.DevTools.writeStart(DevTools.java:284)
   at com.sun.facelets.util.DevTools.writeComponent(DevTools.java:189)
   at com.sun.facelets.util.DevTools.writeComponent(DevTools.java:207)
   at com.sun.facelets.util.DevTools.writeComponent(DevTools.java:207)
   at com.sun.facelets.util.DevTools.writeComponent(DevTools.java:207)
   at com.sun.facelets.util.DevTools.writeComponent(DevTools.java:207)
   at com.sun.facelets.util.DevTools.debugHtml(DevTools.java:133)

Now I understand that the Widget has been detatched from the JPA EntityManager by this time. But when I click that link and come to the details page, I would like the entity to be smart enough to open another session behind the scenes and grab the information it now needs.

Here is my components.xml:

Code:

<persistence:entity-manager-factory name="emf" persistence-unit-name="myWebapp" />
<persistence:managed-persistence-context name="em" auto-create="true" entity-manager-factory="#{emf}" />
<transaction:entity-transaction entity-manager="#{em}"/>

I read at http://docs.jboss.com/seam/2.0.0.GA/reference/en/html/persistence.html#persistence.seam-managed-transactions that my setup in components.xml where I specify this:

<persistence:managed-persistence-context name="em" auto-create="true" entity-manager-factory="#{emf}" />

should set a conversation-scoped persistence context. Clearly, that is not the case. Could the FullTextEntityManager be an issue here?

Thanks for any insight.

neilac333 · **Joined:** Fri Oct 05, 2007 1:17 pm **Posts:** 78

In addition, I was curious how/where the FTEM closes the session.

When I get back to the office, I am going to try injecting an EntityManager instance with @In and manually constructing an instance of FTEM in a method annotated with @Create--rather than have the FTEM injected directly. Since my setup should mean that my EntityManager is conversation-scoped, maybe this will help the session stay open for the duration of the conversation.

Thanks.

neilac333 · **Joined:** Fri Oct 05, 2007 1:17 pm **Posts:** 78

In case this helps, here is the log for when I click the link to go to the details page:

Code:

Mar 2008 14:41:23,662: DEBUG org.hibernate.transaction.JDBCTransaction - commit
Mar 2008 14:41:23,662: DEBUG org.hibernate.impl.SessionImpl - automatically flushing session
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.JDBCContext - before transaction completion
Mar 2008 14:41:23,662: DEBUG org.hibernate.impl.SessionImpl - before transaction completion
Mar 2008 14:41:23,662: DEBUG org.hibernate.transaction.JDBCTransaction - re-enabling autocommit
Mar 2008 14:41:23,662: DEBUG org.hibernate.transaction.JDBCTransaction - committed JDBC Connection
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.JDBCContext - after transaction completion
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.ConnectionManager - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
Mar 2008 14:41:23,662: DEBUG org.hibernate.impl.SessionImpl - after transaction completion
Mar 2008 14:41:23,672: DEBUG org.hibernate.transaction.JDBCTransaction - begin
Mar 2008 14:41:23,672: DEBUG org.hibernate.jdbc.ConnectionManager - opening JDBC connection
Mar 2008 14:41:23,672: DEBUG org.hibernate.transaction.JDBCTransaction - current autocommit status: true
Mar 2008 14:41:23,672: DEBUG org.hibernate.transaction.JDBCTransaction - disabling autocommit
Mar 2008 14:41:23,672: DEBUG org.hibernate.jdbc.JDBCContext - after transaction begin
Mar 2008 14:41:23,672: DEBUG org.hibernate.impl.SessionImpl - setting flush mode to: MANUAL

I should also mention that the Seam debug page does not have the FullTextEntityManager, or any EntityManager for that matter, in any context.

Again, any insight into how to control the commit of the FTEM and the closing of the session is much appreciated.

Thanks.

emmanuel · **Posted:** Sat Mar 08, 2008 1:06 pm

A conversation has to be started and ended, are you marking the conversation boundaries?

FTEM lifecycle is exactly the same as a regular EM. Actually FTEM, is sjust a wrapper on top of EM

neilac333 · **Joined:** Fri Oct 05, 2007 1:17 pm **Posts:** 78

See, that's the confusing thing. I am indeed in the midst of a conversation. The action running the show is in conversational scope. The object that is holding onto the FTEM is in the conversation context. And at no point in the interaction I describe is the conversation ended.

I have even verified that the object holding onto the FTEM is in the conversational context through a SeamTest.

Perhaps some code is in order.

Here is the relevant part of the action:

Code:

@Name("searchAction")
@Scope(value = ScopeType.CONVERSATION)
public class SearchAction extends Object implements Serializable {
.
.
.
   @In(create = true)
   @Out(scope = ScopeType.CONVERSATION)
   private Search search;
}

Now the component called "search" is the one that actually uses Hibernate Search to look for widgets. It therefore has the FTEM with which to do that search. Here is the relevant part of that class:

Code:

@Name("search")
public class SearchImpl extends Object implements Search, Serializable {
.
.
.
   @In
   private FullTextEntityManager em;
.
.
.
}

Finally, I just checked the Seam Debug page. It actually seems like everything is in the conversation context as it should be.

Here is the FTEM:

Code:

Component (em) 
class class org.jboss.seam.persistence.ManagedPersistenceContext 
componentName em 
entityManager org.jboss.seam.persistence.FullTextEntityManagerProxy@1c29764 
entityManagerFactory org.jboss.seam.core.Expressions$1@1c28d46 
entityManagerFactoryFromJndiOrValueBinding org.hibernate.ejb.EntityManagerFactoryImpl@240acac 
filters [] 
persistenceUnitJndiName java:/em 
toString() ManagedPersistenceContext(java:/em)

And here is the "search" component:

Code:

Component (search) 
class class gov.nist.srm.persistence.search.SearchImpl_$$_javassist_1 
component Component(srmSearch) 
currentPage 0 
description   
keyWords  
name test
number  
resultsPerPage 10 
totalResultCount 1 
toString() com.myapp.persistence.search.SearchImpl@1c4a001

Since everything is in the conversation context and the conversation isn't over, why is the Session closed?

Any insight here is appreciated. I know I can probably apply some hack to work around this, but this seems like something I would like to solve correctly as soon as possible.

Thanks.

neilac333 · **Joined:** Fri Oct 05, 2007 1:17 pm **Posts:** 78

Oh and here is a snippet of the log:

Code:

Mar 2008 14:41:23,662: DEBUG org.hibernate.transaction.JDBCTransaction - commit
Mar 2008 14:41:23,662: DEBUG org.hibernate.impl.SessionImpl - automatically flushing session
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.JDBCContext - before transaction completion
Mar 2008 14:41:23,662: DEBUG org.hibernate.impl.SessionImpl - before transaction completion
Mar 2008 14:41:23,662: DEBUG org.hibernate.transaction.JDBCTransaction - re-enabling autocommit
Mar 2008 14:41:23,662: DEBUG org.hibernate.transaction.JDBCTransaction - committed JDBC Connection
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.JDBCContext - after transaction completion
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
Mar 2008 14:41:23,662: DEBUG org.hibernate.jdbc.ConnectionManager - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
Mar 2008 14:41:23,662: DEBUG org.hibernate.impl.SessionImpl - after transaction completion
Mar 2008 14:41:23,672: DEBUG org.hibernate.transaction.JDBCTransaction - begin
Mar 2008 14:41:23,672: DEBUG org.hibernate.jdbc.ConnectionManager - opening JDBC connection
Mar 2008 14:41:23,672: DEBUG org.hibernate.transaction.JDBCTransaction - current autocommit status: true
Mar 2008 14:41:23,672: DEBUG org.hibernate.transaction.JDBCTransaction - disabling autocommit
Mar 2008 14:41:23,672: DEBUG org.hibernate.jdbc.JDBCContext - after transaction begin
Mar 2008 14:41:23,672: DEBUG org.hibernate.impl.SessionImpl - setting flush mode to: MANUAL

emmanuel · **Posted:** Sun Mar 09, 2008 6:57 pm

give it a try with a regular criteria query, I expect the same to happen.

neilac333 · **Joined:** Fri Oct 05, 2007 1:17 pm **Posts:** 78

No need, Emmanuel. I trust you!

My next order of business is figuring out why my conversation is ending, so this is definitely more an issue of my understanding of Seam than a Hibernate Search issue.

I just got a tip that the Seam debug page might be swallowing an exception that causes a rollback and therefore ends the conversation.

Thanks.