Mapping an Enum with JPA

Question

I'm trying to map a string stored in the database (ex. ABC1, BCD2) to an enum (ABC_1, BCD_2).

With hibernate I was able to do this with the following hibernate mapping

<typedef name="LinkEnum" class="GenericEnumUserType">
 <param name="enumClass">types.LinkEnum</param>
 <param name="identifierMethod">value</param>
 <param name="valueOfMethod">fromValue</param>
</typedef>

and in the LinkEnum

@XmlType(name = "LinkEnum")
@XmlEnum
public enum LinkEnum {
@XmlEnumValue("ABC1")
ABC_1("ABC1"),
@XmlEnumValue("BCD2")
BCD_2("BCD2");
private final String value;
LinkEnum(String v) {
 value = v;
}
public String value() {
 return value;
}
public static LinkEnum fromValue(String v) {
 for (LinkeEnum c: LinkEnum.values()) {
 if (c.value.equals(v)) {
 return c;
 }
 }
 throw new IllegalArgumentException(v);
}
}

In the JPA class, I'm trying to do the same kind of mapping, however it's having a problem mapping the enum still. Is there an equivalent way to do this with JPA?

private LinkEnum link;
@Enumerated(EnumType.STRING)
@Column(name = "LINK", nullable = false, length = 8)
public LinkEnum getLink() {
 return this.link;
}

• user3460409: Can we see the entire class definition ?

Answer 1

You could also use a javax.persistence.AttributeConverter (gives your more freedom than the above solution).

For this, implement a class that implements AttributeConverter and annotate your member in the class as follows:

@Convert(converter = NameOfYourConverter.class)

Answer 2

There's a good explanation on the documentation of @Enumerated

public enum EmployeeStatus {FULL_TIME, PART_TIME, CONTRACT}
public enum SalaryRate {JUNIOR, SENIOR, MANAGER, EXECUTIVE}
@Entity public class Employee {
 //@Enumerated is not mandatory. If it's not specified, It assumes to be an ORDINAL (by default)
 public EmployeeStatus getStatus() {...}
 ...
 @Enumerated(EnumType.STRING)
 public SalaryRate getPayScale() {...}
 ...

}

https://docs.oracle.com/javaee/7/api/javax/persistence/Enumerated.html

Answer 3

Define your Enum like this :

public enum LinkEnum {ABC_1("ABC1"), BCD_2("BCD2")}

And your entity, you can annotated like this :

@Enumerated(EnumType.STRING)
 public LinkEnum getLinkEnum() {...}

• Anas Lachheb: Any news ? Do you fix your problem ?