This interface should be implemented by enums which store an int value for database or file persistence.
Once defined this int value should NEVER CHANGE even if new enum constants are added or modified.
Returns the int value to be stored in the database or file.
Method Detail
getPersistentId
int getPersistentId()
Returns the int value to be stored in the database or file.
Note that the implementing Enum must also have a static method named fromPersistentId(int).
This ensures that the Enum can be instantiated from the int read from database or file.