public class YEnabledTransitionSet
This class collects the set of all currently enabled transitions (ie. tasks) of a net.
It is designed to provide a completely correct implementation of the YAWL deferred
Enabled transitions are grouped by the id of the enabling place (condition). For
each place: if there is one or more composite tasks enabled, one of the composite
tasks is chosen (randomly if more than one) and all other tasks are not fired;
otherwise, all the atomic tasks are enabled, allowing a choice to be made from the
environment, and each atomic task is 'stamped' with an identifier that services may
use to identify tasks that are part of the same group.
This class is used exclusively by YNetRunner's continueIfPossible() and fireTasks()
Author: Michael Adams