Thanks for the reply Rick. That does the trick for one field, but this
class is used heavily throughout the model. If possible I'd like to create
a custom field mapping, so that every time a UUID is encountered, this
mapping happens automatically. I've created a custom field mapping.
public class UUIDValueHandler extends ByteArrayValueHandler {
@Override
public Object toDataStoreValue(ValueMapping vm, Object val, JDBCStore
store) {
final byte[] data = UUIDSerializer.toBytes((com.eaio.uuid.UUID)
val);
return super.toDataStoreValue(vm, data, store);
}
@Override
public Object toObjectValue(ValueMapping vm, Object val) {
byte[] data = (byte[]) val;
final UUID uuid = UUIDSerializer.fromBytes(data);
return uuid;
}
}
However, it's not clear to me how to configure this as a plugin via the JPA
configuration. I searched through the documentation, but I can't find any
examples for how to do this. I referenced this section.
http://ci.apache.org/projects/openjpa/trunk/docbook/manual.html#ref_guide_mapping_custom_field_conf
However when I navigate to the reference of section 4 it takes me to this
section.
http://ci.apache.org/projects/openjpa/trunk/docbook/manual.html#ref_guide_mapping_defaults
Should I define a property as follows?
<property name="openjpa.jdbc.MappingDefaults"
value="FieldStrategies='com.eaio.uuid.UUID=com.spidertracks.aviator.dataaccess.jpa.mysql.UUIDValueHandler'"/>
On 19 March 2014 08:56, Rick Curtis <[email protected]> wrote:
> Todd -
>
> Take a look at @Externalizer/@Factory in the user manual[1]. Below is a
> snippet of code where I have a String field in my Entity, but the backing
> column in the DB is an int. The Externalizer/Factory methods convert values
> from/to the database. Let me know how this goes.
>
> Thanks,
> Rick
>
> @Id
>
>
> @Externalizer("org.apache.openjpa.persistence.kernel.common.apps.RuntimeTest1.toDb")
>
>
> @Factory("org.apache.openjpa.persistence.kernel.common.apps.RuntimeTest1.fromDb")
> private String intField;
>
> public static int toDb(String val){
> return Integer.valueOf(val);
> }
>
> public static String fromDb(int val) {
> return String.valueOf(val);
> }
>
> [1]
>
> http://ci.apache.org/projects/openjpa/trunk/docbook/manual.html#ref_guide_pc_extern
>
>
> On Wed, Mar 19, 2014 at 12:10 AM, Todd Nine <[email protected]> wrote:
>
> > Hi all,
> > We're migrating from a Key/Value system to MySQL for some components of
> > our system for easier administration and maintenance. As part of this
> > migration, we need to retain the time UUIDs that have been generated for
> > primary keys. I'm having a hard time mapping this. I have the
> following.
> >
> > @Id
> > @Column( columnDefinition = "BINARY(16)", length = 16 )
> > private UUID id;
> >
> > However this always seems to fail. I'm on the latest MySQL version
> 5.6.16
> > GA and Open JPA 2.2.2 I've found this old thread, but it's not quite what
> > I'm looking for. I'm really struggling to find the documentation on how
> to
> > declare and implement custom type converters. Converting a UUID to a
> binary
> > array of length 16 is trivial, as is creating a new UUID instance from
> > those bytes. I'm just not sure how to plug in to the JPA framework to
> make
> > it happen. Any advice would be greatly appreciated.
> >
> > Thanks,
> > Todd
> >
>
>
>
> --
> *Rick Curtis*
>
