Precedence Property Pattern


To describe relationships between a pair of events/states where the occurrence of the first is a necessary pre-condition for an occurrence of the second. We say that an occurrence of the second is enabled by an occurrence of the first.

Example Mappings

In these mappings P is the consequent and S is the enabling state/event.

Examples and Known Uses

Precedence properties occur quite commonly in specifications of concurrent systems. One common example is in describing a requirement that a resource is only granted in response to a request.


Note that a Precedence property is like a converse of a Response property. Precedence says that some cause precedes each effect, and Response says that some effect follows each cause. They are not equivalent, because a Response allows effects to occur without causes (Precedence similarly allows causes to occur without subsequent effects).

Note that this pattern does not require that each occurrence of a consequent will have its own occurrence of an enabling condition.

This is an Order pattern.