@TypeConverter

Use @TypeConverter to modify data values during the reading and writing of a mapped attribute.

Annotation Elements

Table 2-72 describes this annotation's elements.

Table 2-72 @TypeConverter Annotation Elements

Annotation Element	Description	Default
`name`	(Required) The `String` name for your converter. This name must be unique across the persistence unit.	none
`dataType`	(Optional) The `type` stored in the database.	`void.class`^Foot 1
`objectType`	(Optional) The `type` stored on the entity.	`void.class`^Footref 1

^Footnote 1The default is inferred from the type of the persistence field or property.

Usage

Each TypeConverter must be uniquely named and can be defined at the class, field and property level and can be specified within an Entity, MappedSuperclass and Embeddable class. A TypeConverter is always specified by using an @Convert annotation

You can place a @TypeConverter on a Basic, BasicMap or BasicCollection mapping.

Oracle TopLink also includes @ObjectTypeConverter and @StructConverter converters.

Examples

Example 2-116 shows how to use the @TypeConverter annotation to convert the Double value stored in the database to a Float value stored in the entity.

Example 2-116 Using the @TypeConverter Annotation

@Entity
public class Employee implements Serializable{

...

  @TypeConverter (
    name="doubleToFloat",
    dataType=Double.class,
    objectType=Float.class,
  )
  @Convert("doubleToFloat")
  public Number getGradePointAverage() {
    return gradePointAverage;
  }

...
}