[Hibernate-issues] [Hibernate-JIRA] Closed: (HB-335) Full object tree not loaded with many to many associations

[<leg...@at...>]

Message:

   The following issue has been closed.

   Resolver: Gavin King
       Date: Mon, 15 Sep 2003 9:28 AM

Thanks, this is fixed in CVS.
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View the issue:

  http://opensource.atlassian.com/projects/hibernate/secure/ViewIssue.jspa?key=HB-335


Here is an overview of the issue:
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        Key: HB-335
    Summary: Full object tree not loaded with many to many associations
       Type: Bug

     Status: Closed
   Priority: Major
 Resolution: FIXED

    Project: Hibernate2
 Components: 
             core
   Fix Fors:
             2.1 beta 4
   Versions:
             2.1 beta 2

   Assignee: 
   Reporter: Huguette

    Created: Mon, 15 Sep 2003 8:43 AM
    Updated: Mon, 15 Sep 2003 9:28 AM
Environment: Win2000 - MySQL

Description:
I've got 3 classes A, B and C and 2 many to many relations between A and B and between B and C. Both are not lazy.
When I do following:
open session
load an instance of A
close session
iterate over A.getBs()
iterate over B.getCs()

an exception is thrown:
net.sf.hibernate.LazyInitializationException: Failed to lazily initialize a collection - no Session
when a try to access B.getCs()

A look at the traces shows that hibernate did not generate the SQL query to load the C objects. 

CODE :
*******************************************************************

package com.lge.test;

import java.util.Iterator;

import net.sf.hibernate.Session;
import net.sf.hibernate.SessionFactory;
import net.sf.hibernate.Transaction;
import net.sf.hibernate.cfg.Configuration;


public class TestManyToMany {


  private SessionFactory sessionFactory;

  public TestManyToMany() throws Exception {
    Configuration cfg = new Configuration();
    cfg.addClass( M2MclassA.class);
    cfg.addClass( M2MclassB.class);
    cfg.addClass( M2MclassC.class);
    this.sessionFactory = cfg.buildSessionFactory();
  }
  
  public void doTest1() throws Exception {
    Session session = this.sessionFactory.openSession();
    M2MclassB objB = (M2MclassB)session.find("from com.lge.test.M2MclassB as b where b.name = 'objB'").get(0);
    session.close();
    for (Iterator iter = objB.getChildren().iterator(); iter.hasNext();) {
      System.out.println( iter.next());
    }
    System.out.println("Test 1 OK");
  }
  public void doTest2() throws Exception {
    Session session = this.sessionFactory.openSession();
    M2MclassA objA = (M2MclassA)session.find("from com.lge.test.M2MclassA as a where a.name = 'objA'").get(0);
    session.close();
    for (Iterator iter = objA.getChildren().iterator(); iter.hasNext();) {
      M2MclassB child = (M2MclassB)iter.next();
      System.out.println( "M2MclassB "+child);
      for (Iterator iterator = child.getChildren().iterator(); iterator.hasNext();) {
        System.out.println( "  "+iterator.next());
      }
    }
    System.out.println("Test 2 OK");
  }
  public void init() throws Exception {
    Session session = this.sessionFactory.openSession();
    Transaction t = session.beginTransaction();
    M2MclassA objA = new M2MclassA( "objA");
    M2MclassB objB = new M2MclassB( "objB");

    M2MclassC c1 = new M2MclassC("c1");
    M2MclassC c2 = new M2MclassC("c2");

    objB.addChild( c1);
    objB.addChild( c2);
    objA.addChild(objB);

    session.save( c1);
    session.save( c2);
    session.save(objB);
    session.save(objA);
    session.flush();
    t.commit();
    session.close();
  }
  
  /**
   * @param args command line arguments
   * @exception 
   */
  public static void main(String[] args) throws Exception {
    TestManyToMany test = new TestManyToMany();
    test.init();
    test.doTest1();
    test.doTest2();
  }
}
*****************************************************
package com.lge.test;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;


public class M2MclassA implements Serializable {

  private Long id;
  private Set children = new HashSet(); 
  private String name;
  
  public M2MclassA(){}
  public M2MclassA( String name){ setName(name);}

  public void setChildren( Set children)  { this.children = children; }
  public Set getChildren() { return this.children; }
  public void addChild( M2MclassB child) { this.children.add( child); }
  public void removeChild( M2MclassB child) { this.children.remove(child); }
  
  public Long getId() { return this.id; }
  public void setId(Long id) { this.id = id; }

  public String getName() { return this.name; }
  public void setName(String name) { this.name = name; }

  public String toString() { return getName();}
}
*****************************************************
package com.lge.test;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;


public class M2MclassB implements Serializable {

  private Long id;
  private Set children = new HashSet(); 
  
  private String name;
  
  public M2MclassB(){}
  public M2MclassB( String name){ setName(name);}

  public void setChildren( Set children)  { this.children = children; }
  public Set getChildren() { return this.children; }
  public void addChild( M2MclassC child) { this.children.add( child); }
  public void removeChild( M2MclassC child) { this.children.remove(child); }
  
  public Long getId() { return this.id; }
  public void setId(Long id) { this.id = id; }

  public String getName() { return this.name; }
  public void setName(String name) { this.name = name; }

  public String toString() { return getName();}

}
********************************************************
package com.lge.test;

import java.io.Serializable;


public class M2MclassC implements Serializable {

  private Long id;
  private String name;
  public M2MclassC(){}

  public M2MclassC( String name){ setName( name);}
  
  public String getName() { return this.name; }
  public void setName(String name) { this.name = name; }
  public Long getId() { return this.id; }
  public void setId(Long id) { this.id = id; }
  public String toString() { return getName();}

}
*********************************************************
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
  <class name="com.lge.test.M2MclassA" table="TABLE_A">
    <id column="ID" name="id" unsaved-value="null">
      <generator class="native"/>
    </id>
    <property column="NAME" length="10" name="name" not-null="true" type="java.lang.String"/>
    <set name="children" table="A2B" lazy="false">
      <key column="parent_id" />
      <many-to-many class="com.lge.test.M2MclassB" column="child_id" />
    </set>
  </class>
</hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
  <class name="com.lge.test.M2MclassB" table="TABLE_B">
    <id column="ID" name="id" unsaved-value="null">
      <generator class="native"/>
    </id>
    <property column="NAME" length="10" name="name" not-null="true" type="java.lang.String"/>
    <set name="children" table="B2C" lazy="false">
      <key column="parent_id" />
      <many-to-many class="com.lge.test.M2MclassC" column="child_id" />
    </set>
  </class>
</hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
  <class name="com.lge.test.M2MclassC" table="TABLE_C">
    <id column="ID" name="id" unsaved-value="null">
      <generator class="native"/>
    </id>
    <property column="NAME" length="10" name="name" not-null="true" type="java.lang.String"/>
  </class>
</hibernate-mapping>



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