Join (Vertical)   A join is a kind of pseudostate that re-unites two or more incoming transitions. All of the incoming transitions must have fired before the outgoing transition will fire.

Explanation

Many systems require that a number of actions are carried out or performed at the same time. A join reunites a number of transitions that have been divided by a fork. It is important that the concurrent behavior is reunited otherwise the executing system would not conclude in a predictable way. The fork should not be confused with a merge that also has a number of incoming transitions, the important difference being that a merge reunites the branches of a decision.

Important Points

Joins are not commonly named.

A join, like any UML element can be named, but they are commonly not named as it often adds little meaning. The meaning is expressed in the transitions that unite at the join and the parts of the diagram from which they have originated.

Related Entries

Fork (Vertical)  Paired Element,  Graphically Similar A fork is related to a join as a paired element. The fork "splits" a single flow into two or more flows, which can be re-united by one or more subsequent joins.