My User class has a Set of groups. In the table of course there are multiple rows representing this association, however when I select all users I want to consolidate all groups in one single Set. Following is the information about my class and mapping file. I am faily new in ORM space, just started a week back and have deadline next week. I don't understand what went wrong, it was working until I added that association. Any help will be greatly appreciated.

Thanks,
Meghana

-------------------------------------------------------------------------------

Hibernate version: 3

Mapping documents:
------------------------ User.hbm.xml -----------------------------------
<hibernate-mapping>
<class name="com.serena.dashboard.security.users.User" table="USERS">
<id name="id" column="ID" />
<property name="userName" column="USER_NAME" />
<property name="fullName" column="FULL_USER_NAME"/>
<set name="groups" inverse="true">
<key column="MEMEBER_USER_NAME_KEY"/>
<many-to-many class="com.serena.dashboard.security.users.Group"/>
</set>

<property name="email" column="EMAIL_ADDR"/>
</class>
</hibernate-mapping>

---------------------------------- User.java -------------------------------
package com.serena.dashboard.security.users;

import java.util.Set;

public class User {
private int id;
private String userName;
private String fullName;
private Set groups;
private String email;

public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}

public String getUserName() {
return this.userName;
}
public void setUserName( String userName ) {
this.userName = userName;
}
public String getFullName() {
return this.fullName;
}
public void setFullName( String fullName ) {
this.fullName = fullName;
}
public Set getGroups() {
return this.groups;
}
public void setGroups( Set groups ) {
this.groups = groups;
}

//utility method not needed by Hibernate
public void addGroup( Group group ) {
if( group == null )
throw new IllegalArgumentException("Null Group");
group.getUsers().add( this );
groups.add( group );
}
public String getEmail(){
return email;
}
public void setEmail( String email ){
this.email = email;
}
}

Code between sessionFactory.openSession() and session.close():
hiberSession = HibernateUtil.getSessionFactory().getCurrentSession();
hiberSession.beginTransaction();
String hqlStatement = "select * from User as user where user.userName like '" + searchCriteria.getUserName()+ "' and user.fullName like '" + searchCriteria.getFullName()+ "' and user.email like '" + searchCriteria.getEmail() + "'";
List result = null;
try {
result = hiberSession.createQuery(hqlStatement).list();
}
catch( Throwable t ){
t.printStackTrace();
}
hiberSession.getTransaction().commit();

Full stack trace of any exception that occurs:
Caused by: java.lang.NoSuchMethodError: org.hibernate.hql.antlr.HqlBaseParser.re
cover(Lantlr/RecognitionException;Lantlr/collections/impl/BitSet;)V
at org.hibernate.hql.antlr.HqlBaseParser.selectClause(HqlBaseParser.java
:1391)
at org.hibernate.hql.antlr.HqlBaseParser.selectFrom(HqlBaseParser.java:1
106)
at org.hibernate.hql.antlr.HqlBaseParser.queryRule(HqlBaseParser.java:70
2)
at org.hibernate.hql.antlr.HqlBaseParser.selectStatement(HqlBaseParser.j
ava:296)
at org.hibernate.hql.antlr.HqlBaseParser.statement(HqlBaseParser.java:15
9)
at org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.j
ava:238)
at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorIm
pl.java:155)
at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl
.java:105)
at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:74)
at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:53)
at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCa
che.java:71)
at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessio
nImpl.java:108)
at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImp
l.java:88)
at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1540)
... 66 more

Name and version of the database you are using:
Oracle 9i
The generated SQL (show_sql=true):
NA
Debug level Hibernate log excerpt:
NA

Can anyone please answer my question? I read 'hibernate in action' book and the code looks ok to me. Can someone please point out what am I doing wrong?

What is the exact hibernate version you're using? I can't find an org.hibernate.hql.antlr package in 3.0.5 or 3.1.1. Not even in 2.1...

I'm told that HQL has lost the "as" variant of HQL aliasing in 3.1.2, so if that's what you're using, try "from User user" instead of "select * from User as user".

I know it has nothing to do with your problem, but you should try using either Criteria or HQL + named parameters instead of that kludgey string building. It completely bypasses JDBC statement precompilation, which is useful if the query gets called more than once during the lifetime of a single JDBC connection.

NoSuchMethodError's like that are usually the result of incorrect versions of supporting libraries in your class path. In this case maybe the correct version of "antlr-XXXX.jar" but yes knowing which version of Hibernate you are using affects which dependant libraries you need.

If you can please dump a directory listing of the JAR files in your applications classpath, that might help identify if that is the problem.


I dont use "SELECT *" inside HQL (I even think its illegal???), but just omit it with similar statements, as I thought Hibernate has to be able to deal with a nice object rather than a random list of random columns from randomly joined tables that SQL can give you.



You are asking for a list of "User" objects.

Thank you so much for your replies. I got correct antrl jar in the class path and removed 'select' and 'as' keywords from the query. That seemed to work for simple columns.

But I got 'LazyInitializationException' when it tried to get usergroups which is a 'Set' in my class for individual user. It seems when I try to get the group information in my JSP frontend, it tries to populate the 'Set' at that time so my 'session.commit()' is already called in the user manager's search method and session is lost.

Is there a way to override the 'Late Binding'?

Thank you,
Meghana

JSP... ah lookup "Open Session in View" design pattern. I swear by it :)

What is happening is that you are expecting to be able to reference an object you found in your servlet from your JSP code.

The problem, the normal HibernateSession Singleton pattern people start out with only exists around the Servlet part (the Controller part) and by the time the JSP is executed (the View part) the session is closed.

You can't access proxied objects after you close the session.

http://www.hibernate.org/43.html


Other choices you have (since Open Session in View is not trivial to setup for the beginner):


Configure lazy settings in your map files: http://www.hibernate.org/315.html

If your application is simple maybe you can turn a proxied object into a detached one before you pass it to JSP. Infact if you find out how to do this please post back here :) but I can imagine the reasons why you cant, since do you deep-clone or not and if you deep-clone how do you deal with circular references backed by infinaly huge graphs. Minefield!



No Open Session in View is the way :)

Or be hardcore and create your own Data Transfer Objects for the presenation layer.

You can use threadlocal sessions and Open/Close sessions in filters.
In this way your session will be available in jsp's also.

meghanai_99: There are lots of ways to do what you want. Perhaps the simplest in this case would be to use "join fetch" in your HQL:

dlmiles: select in HQL is fine. It's very useful when you're doing a cross join, or when the thing you want to return isn't the first class in the HQL, e.g. would select all children from one-parent families, or would select all children who live in trailers (assuming that parents live with their children and that only adults own homes ;) )