@Repeatable(value=Converts.class) @Target(value={METHOD,FIELD,TYPE}) @Retention(value=RUNTIME) public @interface Convert
Basic annotation or corresponding
XML element to specify the Basic type.
The Convert annotation should not be used to specify
conversion of the following: Id attributes, version attributes,
relationship attributes, and attributes explicitly denoted as
Enumerated or Temporal. Applications that specify such conversions
will not be portable.
The Convert annotation may be applied to a basic
attribute or to an element collection of basic type (in which case
the converter is applied to the elements of the collection). In
these cases, the attributeName element must not be
specified.
The Convert annotation may be applied to an embedded
attribute or to a map collection attribute whose key or value is of
embeddable type (in which case the converter is applied to the
specified attribute of the embeddable instances contained in the
collection). In these cases, the attributeName
element must be specified.
To override conversion mappings at multiple levels of embedding,
a dot (".") notation form must be used in the attributeName
element to indicate an attribute within an embedded attribute. The
value of each identifier used with the dot notation is the name of the
respective embedded field or property.
When the Convert annotation is applied to a map containing
instances of embeddable classes, the attributeName element
must be specified, and "key." or "value."
must be used to prefix the name of the attribute that is to be converted
in order to specify it as part of the map key or map value.
When the Convert annotation is applied to a map to specify
conversion of a map key of basic type, "key" must be used
as the value of the attributeName element to specify that
it is the map key that is to be converted.
The Convert annotation may be applied to an entity class
that extends a mapped superclass to specify or override a conversion
mapping for an inherited basic or embedded attribute.
Example 1: Convert a basic attribute
@Converter
public class BooleanToIntegerConverter
implements AttributeConverter<Boolean, Integer> { ... }
@Entity
public class Employee {
@Id long id;
@Convert(converter=BooleanToIntegerConverter.class)
boolean fullTime;
...
}
Example 2: Auto-apply conversion of a basic attribute
@Converter(autoApply=true)
public class EmployeeDateConverter
implements AttributeConverter<com.acme.EmployeeDate, java.sql.Date> { ... }
@Entity
public class Employee {
@Id long id;
...
// EmployeeDateConverter is applied automatically
EmployeeDate startDate;
}
Example 3: Disable conversion in the presence of an autoapply converter
@Convert(disableConversion=true)
EmployeeDate lastReview;
Example 4: Apply a converter to an element collection of basic type
@ElementCollection
// applies to each element in the collection
@Convert(converter=NameConverter.class)
List<String> names;
Example 5: Apply a converter to an element collection that is a map or basic values.
The converter is applied to the map value.
@ElementCollection
@Convert(converter=EmployeeNameConverter.class)
Map<String, String> responsibilities;
Example 6: Apply a converter to a map key of basic type
@OneToMany
@Convert(converter=ResponsibilityCodeConverter.class,
attributeName="key")
Map<String, Employee> responsibilities;
Example 7: Apply a converter to an embeddable attribute
@Embedded
@Convert(converter=CountryConverter.class,
attributeName="country")
Address address;
Example 8: Apply a converter to a nested embeddable attribute
@Embedded
@Convert(converter=CityConverter.class,
attributeName="region.city")
Address address;
Example 9: Apply a converter to a nested attribute of an embeddable that is a map key
of an element collection
@Entity public class PropertyRecord {
...
@Convert(attributeName="key.region.city",
converter=CityConverter.class)
@ElementCollection
Map<Address, PropertyInfo> parcels;
}
Example 10: Apply a converter to an embeddable that is a map key for a relationship
@OneToMany
@Convert(attributeName="key.jobType",
converter=ResponsibilityTypeConverter.class)
Map<Responsibility, Employee> responsibilities;
Example 11: Override conversion mappings for attributes inherited from a mapped superclass
@Entity
@Converts({
@Convert(attributeName="startDate",
converter=DateConverter.class),
@Convert(attributeName="endDate",
converter=DateConverter.class)})
public class FullTimeEmployee extends GenericEmployee { ... }
| Modifier and Type | Optional Element and Description |
|---|---|
java.lang.String |
attributeName
The
attributeName element must be specified unless the
Convert annotation is on an attribute of basic type
or on an element collection of basic type. |
java.lang.Class |
converter
Specifies the converter to be applied.
|
boolean |
disableConversion
Used to disable an auto-apply or inherited converter.
|
public abstract java.lang.Class converter