How to map "Map<Field, Picklist> fields"

rafaelsantini · **Posted:** Wed Jun 28, 2006 6:42 pm

How to map this ?

Code:

public class Field {
  int id;
  String name;
}

public class Picklist {
  String title;
  List<String> itens;
}

public class Worksheet {
  int id;
  Map<Field, Picklist> fields;
}

tenwit · **Joined:** Thu Dec 23, 2004 9:08 pm **Posts:** 2008

Code:

<class name="Worksheet" ...>
  ...
  <map name="fields" ...>
    <key="id"/>
    <map-key-many-to-many class="Field" column="field_id"/>
    <one-to-many class="Picklist"/>
  </map>
</class>

rafaelsantini · **Posted:** Thu Jun 29, 2006 5:47 pm

This works.

Now, I have an other question.

The map value might be null. When the value is null means that the field has not a picklist. Example: fields.put(field, null). The problem is that when the value is null the field is not returned. How to solve this?

tenwit · **Joined:** Thu Dec 23, 2004 9:08 pm **Posts:** 2008

Add not-found="ignore" to the one-to-many element.

rafaelsantini · **Posted:** Fri Jun 30, 2006 5:28 pm

not-found="ignore" does not work. The result is the same.

tenwit · **Joined:** Thu Dec 23, 2004 9:08 pm **Posts:** 2008

There's no alternative. Hibernate won't put null values in a map: you either get no key/value pair, or an exception. You'll have to live with no key/value pair, or change your schema to not use null to mean "no picklist".

You could raise a JIRA issue (or find and existing one?) to add a 'not-found="null"' option to those associations.

rafaelsantini · **Posted:** Mon Jul 03, 2006 6:35 pm

I guess that my design was bad. So I have changed to:

Code:

public class Field {
  int id;
  String name;
}

public class Picklist {
  String title;
  List<String> itens;
}

public class WorksheetField {
  Field field;
  Picklist picklist;
}

public class Worksheet {
  int id;
  List<WorksheetField> worksheetFields;
}

Now, all is fine.

Thanks.