Mapping a null property to a primitive

[dawez]

Hi all,

I have been looking for a while to find a possible solution to the problem of retrieving an int (a primitive type) from a database table. The database table contains some nulls and that's where I got "IllegalArgumentException"

This is the mapping of the property posX (in the table this is a FLOAT) which I plan to map to a fload primitive type

the mapping for the class contains:
<property name="posX" column="posX" />

the java class contains
private long posX;

plus the usual getter/setter for this field.

In the Generic DAO class the following piece of code is giving an error in the "return criteria.list();" line. Guess that the problem is that there an assignment of a null value to a primitive field.

Is there a way to "shield" the application against this kind of problems ?

How can I define the posX field / or modify the hibernate mapping file to avoid this problem ?

public List<T> findByCriterion(final Criterion... criterions) {
return getHibernateTemplate().executeFind(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException, SQLException {
Criteria criteria = session.createCriteria(getPersistentClass());
criteria.add(Restrictions.disjunction());
for (Criterion criterion : criterions) {
criteria.add(criterion);
}
return criteria.list();
}
});
}




Thank you in advance for any solutions.

Davide

[ceasaro]

Can't you change the primitive posX to a Integer object. This shouldn't be a problem when you're using java 5 or higher, cause of the autoboxing feature in java 5.

Anyway what value would you like to give the posX field in the database field contains a NULL value? Can't you just asign 0 (zero) in de database to every NULL value.
You can possibly also eliminate them using a where clause in your query.

[dawez]

Thank you ceasaro, implemented your suggestion.

Basically I made the error to use a long for float values So now the posX is defined as Float wrapper. Now the getter and setter have been changed as this.

 //nullable persistent field
   private Float posX;
 public Float getPosX() {
      if (posX == null) {
         return (float) 0;
      } else {
         return posX;
      }
   }

   public void setPosX(Float posX) {
      this.posX = posX;
   }

Now I am able to get the zero back from the NULL values.

Thank you again.