@CollectionOfElements annotation problem

zbhiwandiwala · **Joined:** Fri Aug 03, 2007 4:59 pm **Posts:** 4

Hibernate version: 3.2.1

Name and version of the database you are using: MSSQL server 2005

Hello All,
I have a simple entity called StaticStringDatasource. In this entity I have a list of string values which I want to save to a database. I used the collections annotation to do it.

Code:

@Entity
@Table(name = "Datasources_StaticString")
public class StaticStringDatasource extends Datasource {

    /**
     * List of values associated with the StaticStringDatasource.
     */
    @CollectionOfElements
    @JoinTable(name = "Datasources_StaticString_Values")
    @Size(min = 1)
    @Column(nullable = false)
    private List<String> dataValues;

   //getters and setters...
}

What I am trying to achieve is that when ever the static string datasource is saved the list of string values associated with it should also get saved.

If the supplied list is null and exception must be thrown. Now I think the annotation @Column should attain this, but it doesn't seem to be doing it.

If I supply a null list of string values it still works and no error is thrown. Please help I don't know what I am doing wrong.

thatmikewilliams · **Posted:** Sat Aug 04, 2007 6:12 am

The problem is that even though the list is null there is no corresponding database column that is set to null. Having a null list simple results in zero rows being inserted.

If you're using an entity manager (JPA) you can add validation via annotations either as an event listener or code based validator:

Code:

public class StaticStringDatasource extends Datasource { 
// Code based validator...
   @Transient
   @AssertTrue
   private boolean isValid() {
      return dataValues != null && dataValues.size() > 0;
   }

// or event listener...
   @PrePersist
   @PreUpdate
   private void validateObject() {
      if (dataValues == null || 
            dataValues.size() == 0) {
         throw new MyValidationException("The data values list must contain values");
      }
   }
...

zbhiwandiwala · **Joined:** Fri Aug 03, 2007 4:59 pm **Posts:** 4

Hey,
I managed to validate the data using a code based validator. I put the isValid() method in my base class and also have the method overriden in my sub classes.

In my base class for the @AssertTrue annotation I did not have a message attribute defined. But I do in my sub classes.

The message is by default just read from the base class. So I don't get back the custom message I have defined in each of my subclasses.

Is there a way to get that message?

zbhiwandiwala · **Joined:** Fri Aug 03, 2007 4:59 pm **Posts:** 4

Hey,
I managed to validate the data using a code based validator. I put the isValid() method in my base class and also have the method overriden in my sub classes.

In my base class for the @AssertTrue annotation I did not have a message attribute defined. But I do in my sub classes.

The message is by default just read from the base class. So I don't get back the custom message I have defined in each of my subclasses.

Is there a way to get that message?