com.avaje.ebean.annotation

Annotation Type EnumMapping

@Target(value=TYPE)
 @Retention(value=RUNTIME)
public @interface EnumMapping

For mapping the values of an Enum to and from Database values.

Also refer to the EnumValue approach which probably the preferred now (preferred over using this EnumMapping annotation).

Both of the approaches defined in the JPA have significant problems!!!

Using the ordinal value is VERY RISKY because that depends on the compile order of the enum values. Aka if you change the order of the enum values you have changed their ordinal values and now your DB values are WRONG - a HUGE disaster!!!.

Using the String values of enums is fairly restrictive because in a Database these values are usually truncated into short codes (e.g. "A" short for "ACTIVE") so space used in the database is minimised. Making your enum names match the database values would give them very short less meaningful names - not a great solution.

You can use this annotation to control the mapping of your enums to database values.

The design of this using nameValuePairs is not optimal for safety or refactoring so if you have a better solution I'm all ears. The other solutions would probably involve modifying each enumeration with a method which may be ok.

An example mapping the UserState enum.

...
@EnumMapping(nameValuePairs="NEW=N, ACTIVE=A, INACTIVE=I")
 public enum UserState {
 NEW,
 ACTIVE,
 INACTIVE;
 }

See Also:

EnumValue

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
String	nameValuePairs A comma delimited list of name=value pairs.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
boolean	integerType Defaults to mapping values to database VARCHAR type.
int	length The length of DB column if mapping to string values.

Element Detail

nameValuePairs

public abstract String nameValuePairs

A comma delimited list of name=value pairs.

e.g. "ACTIVE=A, INACTIVE=I, NEW=N".

Where ACTIVE, INACTIVE and NEW are the enumeration values and "A", "I" and "N" are the database values.

This is not really an optimal approach so if you have a better one I'm all ears - thanks.

integerType

public abstract boolean integerType

Defaults to mapping values to database VARCHAR type. If this is set to true then the values will be converted to INTEGER and mapped to the database integer type.

e.g. "ACTIVE=1, INACTIVE=0, NEW=2".

Default:

false

length

public abstract int length

The length of DB column if mapping to string values.

Default:

0