13.19. @watch Example

This is the @watch annotation in a rule's LHS: 
// listens for changes on both firstName (inferred) and lastName
          Person( firstName == $expectedFirstName ) @watch( lastName )

          // listens for all the properties of the Person bean
          Person( firstName == $expectedFirstName ) @watch( * )

          // listens for changes on lastName and explicitly exclude firstName
          Person( firstName == $expectedFirstName ) @watch( lastName, !firstName )

          // listens for changes on all the properties except the age one
          Person( firstName == $expectedFirstName ) @watch( *, !age )

Note

Since doesn't make sense to use this annotation on a pattern using a type not annotated with @PropertyReactive the rule compiler will raise a compilation error if you try to do so. Also the duplicated usage of the same property in @watch (for example like in: @watch( firstName, ! firstName ) ) will end up in a compilation error.
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