Vertical Inheritance with Application ID Hierarchy

Question

Hello,
I want to implement Vertical Inheritance with Application ID Hierarchy,
using a HyperSonic-Database. The essential code is appended.
The following test-application leads to an exception. Things work fine,
if I use one ID-class for all persistent classes; a similar attempt with
horizontal inheritance did work, too.
String attr1Val = getUniqueString();
String attr2Val = getUniqueString();
// ... get PersistenceManager, etc.
// Write something into DB
pm.currentTransaction().begin();
Parent p = new Parent();
p.setattr1("attr1Value");
Child c = new Child();
c.setattr1("qwerty");
c.setattr2(attr2Val);
pm.makePersistent(c);
pm.currentTransaction().commit();
// Query
Query query = pm.newQuery(Child.class,"attr2 == param");
query.declareParameters("String param");
Collection results = (Collection)query.execute(attr2Val);
kodo.util.FatalUserException: Duplicate object ids have been assigned to
two different objects: the identity "1" of class "class foo.Child$ID" was
assigned to both "foo.Child@1f4cbee" and "foo.Child@787d6a". This can
occur when a horizontally or vertically mapped class uses application
identity with an auto-increment field and does not use a hierarchy of
application identity classes.[foo.Child$ID-1]
Can anyone help ?
Thanks.
Lutz
code-pieces:
parent.java:
public class Parent implements Serializable,InstanceCallbacks
private transient PersistenceManager pm = null;
public Long ObjId;
public void setObjId(Long value)
ObjId = value;
// application identity class for Manager; represented as
// a static inner class for the persistable class
public static class ID implements Serializable
static
{ // register persistent class in JVM
Class c = foo.Parent.class;
public Long ObjId;
public ID ()
public ID (String str)
fromString (str);
public String toString ()
return String.valueOf (ObjId);
public int hashCode ()
return ((ObjId == null) ? 0 : ObjId.hashCode ());
public boolean equals (Object obj)
if (this == obj)
return true;
if (obj == null || obj.getClass () != getClass ())
return false;
ID other = (ID) obj;
return ((ObjId == null && other.ObjId == null) ||
(ObjId != null && ObjId.equals (other.ObjId)));
private void fromString (String str)
if ("null".equals (str))
ObjId = null;
else
ObjId = new Long (str);
private String attr1;
public Parent()
public void jdoPreStore()
// Some Action that needs to be done before data is flushed to
datastore...
if (ObjId == null)
if (pm == null)
pm = ResourceManager.getPersistenceMgr("test", "sa", "");
SequenceGenerator gen = KodoHelper.getSequenceGenerator (pm,
Parent.class);
setObjId(new Long(gen.getNext().longValue()));
parent.jdo:
<jdo>
<package name="foo">
<class name="Parent" identity-type="application"
objectid-class="Parent$ID">
<field name="ObjId" persistence-modifier="persistent"
primary-key="true"/>
<field name="attr1" persistence-modifier="persistent"/>
</class>
</package>
</jdo>
child.java:
public class Child extends Parent
implements Serializable,InstanceCallbacks
private transient PersistenceManager pm = null;
public static class ID extends Parent.ID
static
{ // register persistent class in JVM
Class c = foo.Child.class;
public ID()
super();
public ID (String str)
super(str);
public void jdoPreStore()
if (ObjId == null)
if (pm == null)
pm = ResourceManager.getPersistenceMgr("test", "sa", "");
SequenceGenerator gen = KodoHelper.getSequenceGenerator (pm,
Child.class);
setObjId(new Long(gen.getNext().longValue()));
child.jdo:
<jdo>
<package name="foo">
<class name="Child" persistence-capable-superclass="foo.Parent"
identity-type="application" objectid-class="Child$ID">
<extension vendor-name="kodo" key="jdbc-class-map-name"
value="vertical">
<extension vendor-name="kodo" key="table" value="CHILD"/>
<extension vendor-name="kodo" key="ref-column.OBJID"
value="OBJID"/>
</extension>
<field name="attr2" persistence-modifier="persistent"/>
</class>
</package>
</jdo>
generated mappings by "mappingtool -a refresh":
parent.mapping:
<mapping>
<package name="foo">
<class name="Parent">
<jdbc-class-map type="base" table="PARENT"/>
<jdbc-version-ind type="version-number" column="JDOVERSION"/>
<jdbc-class-ind type="in-class-name" column="JDOCLASS"/>
<field name="ObjId">
<jdbc-field-map type="value" column="OBJID"/>
</field>
<field name="attr1">
<jdbc-field-map type="value" column="ATTR1"/>
</field>
</class>
</package>
</mapping>
child.mapping:
<mapping>
<package name="foo">
<class name="Child">
<jdbc-class-map type="vertical" ref-column.OBJID="OBJID"
table="CHILD"/>
<field name="attr2">
<jdbc-field-map type="value" column="ATTR2"/>
</field>
</class>
</package>
</mapping>

Answer 1

Hello,
I want to implement Vertical Inheritance with Application ID Hierarchy,
using a HyperSonic-Database. The essential code is appended.
The following test-application leads to an exception. Things work fine,
if I use one ID-class for all persistent classes; a similar attempt with
horizontal inheritance did work, too.
String attr1Val = getUniqueString();
String attr2Val = getUniqueString();
// ... get PersistenceManager, etc.
// Write something into DB
pm.currentTransaction().begin();
Parent p = new Parent();
p.setattr1("attr1Value");
Child c = new Child();
c.setattr1("qwerty");
c.setattr2(attr2Val);
pm.makePersistent(c);
pm.currentTransaction().commit();
// Query
Query query = pm.newQuery(Child.class,"attr2 == param");
query.declareParameters("String param");
Collection results = (Collection)query.execute(attr2Val);
kodo.util.FatalUserException: Duplicate object ids have been assigned to
two different objects: the identity "1" of class "class foo.Child$ID" was
assigned to both "foo.Child@1f4cbee" and "foo.Child@787d6a". This can
occur when a horizontally or vertically mapped class uses application
identity with an auto-increment field and does not use a hierarchy of
application identity classes.[foo.Child$ID-1]
Can anyone help ?
Thanks.
Lutz
code-pieces:
parent.java:
public class Parent implements Serializable,InstanceCallbacks
private transient PersistenceManager pm = null;
public Long ObjId;
public void setObjId(Long value)
ObjId = value;
// application identity class for Manager; represented as
// a static inner class for the persistable class
public static class ID implements Serializable
static
{ // register persistent class in JVM
Class c = foo.Parent.class;
public Long ObjId;
public ID ()
public ID (String str)
fromString (str);
public String toString ()
return String.valueOf (ObjId);
public int hashCode ()
return ((ObjId == null) ? 0 : ObjId.hashCode ());
public boolean equals (Object obj)
if (this == obj)
return true;
if (obj == null || obj.getClass () != getClass ())
return false;
ID other = (ID) obj;
return ((ObjId == null && other.ObjId == null) ||
(ObjId != null && ObjId.equals (other.ObjId)));
private void fromString (String str)
if ("null".equals (str))
ObjId = null;
else
ObjId = new Long (str);
private String attr1;
public Parent()
public void jdoPreStore()
// Some Action that needs to be done before data is flushed to
datastore...
if (ObjId == null)
if (pm == null)
pm = ResourceManager.getPersistenceMgr("test", "sa", "");
SequenceGenerator gen = KodoHelper.getSequenceGenerator (pm,
Parent.class);
setObjId(new Long(gen.getNext().longValue()));
parent.jdo:
<jdo>
<package name="foo">
<class name="Parent" identity-type="application"
objectid-class="Parent$ID">
<field name="ObjId" persistence-modifier="persistent"
primary-key="true"/>
<field name="attr1" persistence-modifier="persistent"/>
</class>
</package>
</jdo>
child.java:
public class Child extends Parent
implements Serializable,InstanceCallbacks
private transient PersistenceManager pm = null;
public static class ID extends Parent.ID
static
{ // register persistent class in JVM
Class c = foo.Child.class;
public ID()
super();
public ID (String str)
super(str);
public void jdoPreStore()
if (ObjId == null)
if (pm == null)
pm = ResourceManager.getPersistenceMgr("test", "sa", "");
SequenceGenerator gen = KodoHelper.getSequenceGenerator (pm,
Child.class);
setObjId(new Long(gen.getNext().longValue()));
child.jdo:
<jdo>
<package name="foo">
<class name="Child" persistence-capable-superclass="foo.Parent"
identity-type="application" objectid-class="Child$ID">
<extension vendor-name="kodo" key="jdbc-class-map-name"
value="vertical">
<extension vendor-name="kodo" key="table" value="CHILD"/>
<extension vendor-name="kodo" key="ref-column.OBJID"
value="OBJID"/>
</extension>
<field name="attr2" persistence-modifier="persistent"/>
</class>
</package>
</jdo>
generated mappings by "mappingtool -a refresh":
parent.mapping:
<mapping>
<package name="foo">
<class name="Parent">
<jdbc-class-map type="base" table="PARENT"/>
<jdbc-version-ind type="version-number" column="JDOVERSION"/>
<jdbc-class-ind type="in-class-name" column="JDOCLASS"/>
<field name="ObjId">
<jdbc-field-map type="value" column="OBJID"/>
</field>
<field name="attr1">
<jdbc-field-map type="value" column="ATTR1"/>
</field>
</class>
</package>
</mapping>
child.mapping:
<mapping>
<package name="foo">
<class name="Child">
<jdbc-class-map type="vertical" ref-column.OBJID="OBJID"
table="CHILD"/>
<field name="attr2">
<jdbc-field-map type="value" column="ATTR2"/>
</field>
</class>
</package>
</mapping>