As fl ows are merged, no conditions are tested, and there is no waiting for special
events ( Figure 3.50 ).
3.6.7 Fork and Join Nodes
13 The runtime environment of the model must be capable of evaluating the expression. The runtime
environment can also be a human.
FIGURE 3-49
Example for decision nodes.
act Buy soft drink (section)
Pay soft drink
[cannot read card]
[insufficient amount on card] [o.k.]
[else]
Payment by chip
card only
Defi nitions
A fork node is a node in an activity that splits a flow into several concurrent flows.
There is exactly one incoming edge and an arbitrary number of outgoing edges.
A join node is a node in an activity that synchronizes several concurrent fl ows
and joins them into one single fl ow. There is an arbitrary number of incoming
edges and exactly one outgoing edge.
In contrast to a decision node that enables several optional flows, a fork node
creates several concurrent flows. To make this happen, the token that arrives at
the fork node over the incoming edge is copied several times, so that there is one
token available for each outgoing edge.
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