Annotation Interface MapKeyEnumerated

@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface MapKeyEnumerated

Specifies that a map key should be persisted as an enumerated type. The declared type of the annotated property or field must be Map<K,V> where K is a Java enum type. This annotation is always optional.

The MapKeyEnumerated annotation may be used in conjunction with the ElementCollection annotation, OneToMany annotation, or ManyToMany annotation when the key type of the collection is an enum type.

An enum can be mapped as either a string or an integer, where EnumType enumerates the available options. The mapping may be explicitly specified by this annotation.

If a map key of enum type has no explicit MapKeyEnumerated annotation, and if no converter is applied to the key:

• if the enum type has a final field of type String annotated EnumeratedValue, the enumerated type is inferred to be EnumType.STRING;
• otherwise, the enumerated type is taken to be EnumType.ORDINAL.

Example:

public enum ProjectStatus {COMPLETE, DELAYED, CANCELLED, IN_PROGRESS}

public enum SalaryRate {JUNIOR, SENIOR, MANAGER, EXECUTIVE}

@Entity
public class Employee {
    @ManyToMany
    public Projects<ProjectStatus, Project> getProjects() { ... }

    @OneToMany
    @MapKeyEnumerated(STRING)
    public Map<SalaryRate, Employee> getEmployees() { ... }
    ...
}

Since:

2.0

See Also:

• ElementCollection
• OneToMany
• ManyToMany

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
EnumType	value	(Optional) The type used in mapping a map key enum type.

Element Details

value

EnumType value

(Optional) The type used in mapping a map key enum type.

Default:

ORDINAL