| Origin: |
Grand 98 (but there are many earlier examples in the Java APIs) |
| Reason: |
A class needs a semantic attribute, but no specific members. |
| Synopsis: |
Define an empty interface, M.
Say that a class implements interface M.
|
| Example: |
How can one mark a class, C,
whose objects are equal only if they are the same object
(and, thus, use == instead of equals for comparison).
|
| Solution: |
| Marker |
An interface (trivially) implemented by class C. |
e.g., EqualByIdentity. |
|
| See also: |
Java API interfaces java.io.Serializable and
java.rmi.Remote for classic examples.
|