Hi,
My goal is to initialize every item in a lazy collection and for each item in the collection I would like to fetch also a lazy association (a many-to-one association).
E.g: Let A be the parent of my object graph. B is a collection in A (defined as lazy in its hbm file) and C is an object in B(i) (i for some item in B, also declared lazy).
I have tried to achieve that with different hql query within session.createQuery(…) or with createCriteria(...) with setFetchMode(...) etc.
Whatever fetching strategy I choose, I always result with some missing data in the web (you know…the famous LazyInitializationException of Hibernate) this is because I would like (and need!!) to fetch all the above data in my EJB container, closing the session and then passing all data to the web.
My question: Is there a way to fetch all data in class A + all items of collection B + for each item in B – fetching the many-to-one association C ?
Is it possible to do so with one query ?
BTW: I prefer not to declare my fetch strategy in the hbm file, but using it in runtime. Lazy is important for me since sometimes i need just a partial data (e.g need A without its collection B).

10x!!
Hibernate version: 3.0.5

simon.

"fetch all properties" should help

http://www.hibernate.org/hib_docs/v3/re ... ryhql.html

Thanks for replying but fetching all the data through "fetch all properties" works only if you are using bytecode instrumentation

From your link it sais:

well...
1. I am not using bytecode instrumentation.
2. I don't know how to use it.
3. somehow it seems to me that there must be an alternative other than passing my code some instruments...(and I still want the lazy approch).

Any other idea?

Thanks!!

Unless you have disabled bytecode instrumentation with something like
hibernate.cglib.use_reflection_optimizer=false
the bytecode instrumentation is enabled by default and H takes full advantage of it.
I think laziness works only when H is alloved to instrument classes

SORRY!!
but it's not working that way (I didn't disable reflection optimizer of cglib).
Try the simplest sample: Item and its (lazy) bids set/map. try to execute a query, something like:
Item anItem = session.createQuery("from item fetch all properties where id = 1").uniqueResult();
Assuming there is an item row with id 1, you will get only the item data and not the collection (even Hibernate.isInitialized(item.getBids()) will return false!)

???

Thanks!!!

You are right, it does not work. Looks like H bug.
In my test I also see that H reports that property is initialized, but attempt to read values fails.

The code:
public void testCollectionFetchAll() {
long id = createCollection();
Session s;
Transaction t;
CollectionHolder ch;
s = getSessions().openSession();
t = s.beginTransaction();
ch = (CollectionHolder) s.createQuery("from CollectionHolder fetch all properties").uniqueResult();
t.commit();
s.close();
System.out.println("fetch all bclasses Initialized::" +Hibernate.isPropertyInitialized( ch, "bclasses" ));
System.out.println("fetch all bclasses proxy Initialized::" +Hibernate.isInitialized( ch.getBclasses() ));
System.out.println("fetch all ch.bclasses.length = " + ch.getBclasses().size() );
System.out.println("fetch all ch.bclasses[1] = " + ch.getBclasses().get( 1 ) );
}

and output is:
fetch all bclasses Initialized::true
fetch all bclasses proxy Initialized::false
09:26:58,012 ERROR LazyInitializationException:19 - failed to lazily initialize a collection of role: org.hibernate.test.kgi.CollectionHolder.bclasses, no session or session was closed
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.hibernate.test.kgi.CollectionHolder.bclasses, 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.PersistentList.size(PersistentList.java:91)
at org.hibernate.test.kgi.LazynessTest.testCollectionFetchAll(LazynessTest.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at junit.framework.TestCase.runTest(TestCase.java:154)
at org.hibernate.test.TestCase.runTest(TestCase.java:140)
at junit.framework.TestCase.runBare(TestCase.java:127)
at junit.framework.TestResult$1.protect(TestResult.java:106)
at junit.framework.TestResult.runProtected(TestResult.java:124)
at junit.framework.TestResult.run(TestResult.java:109)
at junit.framework.TestCase.run(TestCase.java:118)
at junit.framework.TestSuite.runTest(TestSuite.java:208)
at junit.framework.TestSuite.run(TestSuite.java:203)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:297)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:672)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:567)

"fetch all properties" is *not* meant to fetch associations or collections

Are you making use of the fetch keyword in HQL? It forces query-time loading of objects in collections. It's described in the "Associations and Joins" chapter of the ref docs, section 15.3 in my version.

You can also try Hibernate.initialize(), on the java side.

Gavin, then I suggest adding this note to #14.3 in the documentation, something like:
.... If you are using property-level lazy fetching (with bytecode instrumentation), it is possible to force Hibernate to fetch the lazy properties immediately (in the first query) using fetch all properties. Note: 'fetch all properties' has not affect associations, 'join fetch' should be used instead.

The paragraph #14.3 mentions that but it is easily overlooked during non-linear reading and 'fetch all properties' gives wrong idea regarding its meaning.