@Target(value=METHOD)
@Retention(value=RUNTIME)
@Documented
@UseWith(value=MODULE)
public @interface Optional
Marks a service contribution method within a module as being optional: it is not an error if the contribution does not match against an actual service. In that case, the
method will simply never be invoked. This is occasionally useful when a module is designed to work with another module if the second module is present. Without
optional contributions, you would see hard errors when registry is created, and have to create a layer cake of small modules to prevent such errors.
- Since:
- 5.3
- See Also:
Contribute,
ContributionDef3.isOptional()