Module AtomicStampedReference

module AtomicStampedReference: sig .. end
Atomic containers for stamped values.

type 'a t = java'util'concurrent'atomic'AtomicStampedReference java_instance
The type of atomic containers for stamped values.

WARNING: physical comparison is used by the container.

CONSEQUENCE 1: should be used with caution to store int32, int64, nativeint, or double values as they are wrapped into blocks. Hence, comparisons are done on block addresses rather than on wrapped values.

CONSEQUENCE 2: as OCaml-Java uses boxed values for int values, the container should not be used to store int values.

Any other type can be safely stored (caching of some int values ensure that sum types are correctly handled).
type stamp = int32
The type of stamps.
val make : 'a -> stamp -> 'a t
Returns a new container holding the passed value, with the passed stamp.
val attempt_stamp : 'a t -> 'a -> stamp -> bool
attempt_stamp a e s sets the stamp to s if the current value is e. Returns whether the value of a was equal to e.
val compare_and_set : 'a t ->
'a ->
'a -> stamp -> stamp -> bool
compare_and_set a er ur es us atomically sets the value of a to ur and stamp to us if the current value is er and the current stamp is es. Returns whether the value of a was equal to er and the stamp was equal to es.
val get : 'a t -> 'a * stamp
Returns the current value and stamp.
val get_reference : 'a t -> 'a
Returns the current value.
val get_stamp : 'a t -> stamp
Returns the current stamp.
val set : 'a t -> 'a -> stamp -> unit
set a x s sets the value of a to x, and the stamp to s.
val weak_compare_and_set : 'a t ->
'a ->
'a -> stamp -> stamp -> bool
Similar to AtomicStampedReference.compare_and_set, with a weak semantics: may be faster on some platforms, but does not provide ordering guarantees.

Null value

val null : 'a t
The null value.
val is_null : 'a t -> bool
is_null obj returns true iff obj is equal to null.
val is_not_null : 'a t -> bool
is_not_null obj returns false iff obj is equal to null.


val wrap : 'a t -> 'a t option
wrap obj wraps the reference obj into an option type:
  • Some x if obj is not null;
  • None if obj is null.

val unwrap : 'a t option -> 'a t
unwrap obj unwraps the option obj into a bare reference:
  • Some x is mapped to x;
  • None is mapped to null.