How to read a graph

The graph of the possible executions shows nodes with different shapes and colors, depending on the facts and commitments that hold in the state:

Colors:
  • White state:
    all constraints are satisfied;
  • Yellow state:
    there is a pending constraint to satisfy. It is a state of violation if the interaction ends in that state;
  • Red state:
    a constraint has been violated.

Shapes:
  • Single outline:
    there are some active commitments (not discharged, released or cancelled)
  • Double outline:
    the state does not contain any active commitment
  • Diamond states:
    a before constraint was violated. Diamond states are always colored in red. They can have a single or a double outline, depending on the presence or the absence of active commitments