Abstract invalidator of "something". An example would be a global invalidator for cached constants. How invalidation is performed is considered to be opaque. To invalidate, call #invalidate. To get data associated with the invalidation, use getData; the meaning of this data is Invalidator-implementation-specific. In the case of JSR-292's SwitchPoint, this would return a SwitchPoint to be used for guarding e.g. a cached constant value.