[Hibernate-issues] [Hibernate-JIRA] Created: (HB-108) Mapping non-static inner classes

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  A new issue has been created in JIRA.

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  http://opensource.atlassian.com/projects/hibernate/secure/ViewIssue.jspa?key=HB-108


Here is an overview of the issue:
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        Key: HB-108
    Summary: Mapping non-static inner classes
       Type: New Feature

     Status: Unassigned
   Priority: Minor

    Project: Hibernate2
 Components: 
             core

   Assignee: 
   Reporter: Gunther Schadow

    Created: Tue, 27 May 2003 6:55 PM
    Updated: Tue, 27 May 2003 6:55 PM
Environment: any

Description:
It would be nice if Hibernate could handle true inner classes.
For example, say you have a Person with several addresses:

class Person {
  long   id,
  String name,
  List/*<Address>*/ addresses

  class Address {
    String value;
    String purpose;
  }

  ...
}

whereas the database contains the two tables:

CREATE TABLE Person (
  id   LONG NOT NULL PRIMARY KEY,
  name VARCHAR,
)

CREATE TABLE PersonAddress (
  personId LONG NOT NULL REFERENCES Person(id),
  value   VARCHAR,
  purpose VARCHAR,

  PRIMARY KEY(personId, purpose);
)

and the mapping file would contain

<class name="Person" table="Person">
  <id name="id" type="long">...</id>
  <property name="name" type="string"/>
  <bag name="addresses" lazy="true" table="PersonAddress">
    <key column="personId"/>
    <composite-element class="Person$Address">
      <property name="value" column="value" type="string"/>
      <property name="purpose" column="purpose" type="string"/>
    </composite-element>
  </bag>
</class>

Since personId is NOT NULL in the PersonAddress table, we 
know that we allways will have a Person if we load a 
PersonAddress, and, since PersonAddress is mapped as a
composite element, we can't even load a Person$Address alone
without having a Person in hand. Therefore all requirements
for creating non-static inner classes are fulfilled.

Workaround is of course to use a static inner class in which
the implicit association to the parent class is made explicit.
Since non-static inner classes are a proper idiom of Java,
the goal of "persistence for idiomatic java" makes proper 
handling of non-static inner classes highly desirable.


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