Cascading collection of primitives only saves at flush

mwinkels · **Joined:** Wed Jan 26, 2005 11:01 am **Posts:** 18

Hello,

I'm seeing strange behaviour when saving an entity with a collection of primitives (Double,String,...). When I set the cascade property to CascadeType.ALL and save the parent entity, the collection items are only inserted when the session is flushed (either explicitly or implicitly). If I change the collection to hold entities, that encapsulate the primitive, the collection items are saved eagerly (with the save of the parent entity).

Is this expected behaviour? I would expect the cascading behaviour of a collection to be the same for primitive or entity elements.

Regards,

-Maarten Winkels

mwinkels · **Joined:** Wed Jan 26, 2005 11:01 am **Posts:** 18

I tried to illumenate this with an example:

PrimitiveCollectionParent.java

Code:

package org.hibernate.test.annotations.collectionelement.cascade;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.AccessType;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.OneToMany;

import org.hibernate.annotations.Formula;

@Entity(access=AccessType.FIELD)
public class PrimitiveCollectionParent {
   
   @Id(generate= GeneratorType.AUTO)
   private Integer Id;
   
   @OneToMany(cascade=CascadeType.ALL)
   private List<Double> scores = new ArrayList<Double>();
   
   @Formula(value="(select sum(s.elt) from PrimitiveCollectionParent_scores s where s.PrimitiveCollectionParent_Id=id)")
   private Double totalScore;
   
   public void addScore (double score) {
      scores.add(score);
   }

   public Double getTotalScore() {
      return totalScore;
   }
}

EntityCollectionParent.java

Code:

package org.hibernate.test.annotations.collectionelement.cascade;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.AccessType;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;

import org.hibernate.annotations.Formula;

@Entity(access=AccessType.FIELD)
public class EntityCollectionParent {
   
   @Id(generate= GeneratorType.AUTO)
   private Integer Id;
   
   
   @OneToMany(cascade=CascadeType.ALL,mappedBy="parent")
   private List<Score> scores = new ArrayList<Score>();
   
   @Formula(value="(select sum(s.score) from Score s where s.parent_Id=id)")
   private Double totalScore;
   
   public void addScore (double score) {
      scores.add(new Score(this, score));
   }

   public Double getTotalScore() {
      return totalScore;
   }
}

Score.java

Code:

package org.hibernate.test.annotations.collectionelement.cascade;

import javax.persistence.AccessType;
import javax.persistence.Entity;
import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;

@Entity(access=AccessType.FIELD)
class Score {

   @Id(generate=GeneratorType.AUTO)
   private Integer id;
   
   @ManyToOne
   private EntityCollectionParent parent;
   
   private double score;

   public Score(EntityCollectionParent parent, double score) {
      this.parent = parent;
      this.score = score;
   }
}

PrimitiveCollectionCascadeTest.java

Code:

package org.hibernate.test.annotations.collectionelement.cascade;

import java.io.Serializable;

import org.hibernate.Session;
import org.hibernate.test.annotations.TestCase;

public class PrimitiveCollectionCascadeTest extends TestCase {

   @Override
   protected Class[] getMappings() {
      return new Class[]{PrimitiveCollectionParent.class,EntityCollectionParent.class,Score.class};
   }
   
   public final void testWithoutFlush () {
      PrimitiveCollectionParent parent = new PrimitiveCollectionParent();
      parent.addScore(13.0);
      parent.addScore(24.5);
      Session s = openSession();
      Serializable id = s.save(parent);
      s.close();
      
      s = openSession();
      PrimitiveCollectionParent persisted = (PrimitiveCollectionParent) s.get(PrimitiveCollectionParent.class,id);
      s.close();
      assertEquals(37.5,persisted.getTotalScore());
   }

   public final void testWithFlush () {
      PrimitiveCollectionParent parent = new PrimitiveCollectionParent();
      parent.addScore(13.0);
      parent.addScore(24.5);
      Session s = openSession();
      Serializable id = s.save(parent);
      s.flush();
      s.close();
      
      s = openSession();
      PrimitiveCollectionParent persisted = (PrimitiveCollectionParent) s.get(PrimitiveCollectionParent.class,id);
      s.close();
      assertEquals(37.5,persisted.getTotalScore());
   }
   
   public final void testWithEntities () {
      EntityCollectionParent parent = new EntityCollectionParent();
      parent.addScore(13.0);
      parent.addScore(24.5);
      Session s = openSession();
      Serializable id = s.save(parent);
      s.close();
      
      s = openSession();
      EntityCollectionParent persisted = (EntityCollectionParent) s.get(EntityCollectionParent.class,id);
      s.close();
      assertEquals(37.5,persisted.getTotalScore());
   }
}

As you can see the test works perfectly well when flushing or using a collection of entities. Is this due to the mappedBy property of the collection of entities? If so, I cannot specify "mappedBy"on a collection of primitives (obviously, since the primitive type will not hold a reference to the parent).

mwinkels · **Joined:** Wed Jan 26, 2005 11:01 am **Posts:** 18

The assumption that the "mappedBy" property is responsible for this behaviour seems to be correct. Mapping the entity collection one-to-many unidirectionally with

Code:

@OneToMany(cascade=CascadeType.ALL,fetch=FetchType.EAGER)
@JoinColumn(name="parent_Id")
private List<Score> scores = new ArrayList<Score>();

(removing the other direction from the Score class), shows the same behaviour under flush and no flush.
This could be all due to the "mappedBy" property, but as meantioned before, how do I set this on a collection of primitives?

Cheers,

-Maarten Winkels

emmanuel · **Posted:** Wed Oct 05, 2005 8:53 am

a collection of element has the same lifecycle of its owner entity out of the box

mwinkels · **Joined:** Wed Jan 26, 2005 11:01 am **Posts:** 18

emmanuel wrote:

a collection of element has the same lifecycle of its owner entity out of the box

If so, shouldn't the insert statements for the collection elements be issued when 'save' is caled on the owener? As the test shows, they are not...

emmanuel · **Posted:** Wed Oct 05, 2005 9:34 am

No, cause there is no need to retrieve eagerly an id from them

mwinkels · **Joined:** Wed Jan 26, 2005 11:01 am **Posts:** 18

So this is a "lazy" feature for Hibernate and the fact that it breaks the formula (as the tests show) is anticipated?

emmanuel · **Posted:** Wed Oct 05, 2005 10:28 am

You have to flush before closing, that's mandatory

emmanuel · **Posted:** Wed Oct 05, 2005 10:30 am

And do use transaction