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@Target(value={METHOD,FIELD})
@Retention(value=RUNTIME)
public @interface MapKeyClass
Specifies the type of the map key for associations of type
java.util.Map. The map key can be a basic type, an
embeddable class, or an entity. If the map is specified using Java
generics, the MapKeyClass annotation and associated
type need not be specified; otherwise they must be specified.
The MapKeyClass annotation is used in conjunction
with ElementCollection or one of the collection-valued
relationship annotations (OneToMany or ManyToMany).
The MapKey annotation is not used when
MapKeyClass is specified and vice versa.
Example 1:
@Entity
public class Item {
@Id int id;
...
@ElementCollection(targetClass=String.class)
@MapKeyClass(String.class)
Map images; // map from image name to image filename
...
}
Example 2:
// MapKeyClass and target type of relationship can be defaulted
@Entity
public class Item {
@Id int id;
...
@ElementCollection
Map<String, String> images;
...
}
Example 3:
@Entity
public class Company {
@Id int id;
...
@OneToMany(targetEntity=com.example.VicePresident.class)
@MapKeyClass(com.example.Division.class)
Map organization;
}
Example 4:
// MapKeyClass and target type of relationship are defaulted
@Entity
public class Company {
@Id int id;
...
@OneToMany
Map<Division, VicePresident> organization;
}
ElementCollection,
OneToMany,
ManyToMany| Required Element Summary | |
|---|---|
java.lang.Class |
value
(Required) The type of the map key. |
| Element Detail |
|---|
public abstract java.lang.Class value
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Copyright © 2009 Sun Microsystems, Inc. All Rights Reserved. Use is subject to license terms.
Generated on 24-November-2009 03:24