Class StateEngine

java.lang.Object
org.glassfish.pfl.basic.fsm.StateEngine
public class StateEngine extends Object
Encodes the state transition function for a finite state machine.

  • Field Details

    • emptyAction

      private static Action emptyAction

    • initializing

      private boolean initializing

    • defaultAction

      private Action defaultAction

    • stateKinds

      private Map<State.Kind, Set<State>> stateKinds

    • unmodifiableStateKinds

      private Map<State.Kind, Set<State>> unmodifiableStateKinds

  • Constructor Details

    • StateEngine

      private StateEngine()

  • Method Details

    • create

      public static StateEngine create()
      Create an empty uninitialized state engine.

    • dprint

      private void dprint(String msg)

    • getKindSet

      private Set<State> getKindSet(State.Kind kind)

    • updateStateMap

      private void updateStateMap(State oldState, State newState)

    • getStates

      public Set<State> getStates(State.Kind kind)
      Return the set of final states for this state engine. This may be an empty set.

    • add

      public StateEngine add(State oldState, Input input, Guard guard, Action action, State newState)
      Add a new transition (old,in,guard,act,new) to the state engine. Multiple calls to add with the same old and in are permitted, in which case only a transition in which the guard evaluates to true will be taken. If no such transition is enabled, a default will be taken. If more than one transition is enabled, one will be chosen arbitrarily. This method can only be called before done(). An attempt to call it after done() results in an IllegalStateException.

    • add

      public StateEngine add(State oldState, Set<Input> input, Guard guard, Action action, State newState)
      Repeatedly calls add( State, Input, Guard, Action, State ) for each element of input.

    • add

      public StateEngine add(State oldState, Input input, Action action, State newState)
      Add a transition with a guard that always evaluates to true.

    • add

      public StateEngine add(State oldState, Set<Input> input, Action action, State newState)
      Repeatedly call add( State, Input, Action, State ) for each element of input.

    • setDefault

      public StateEngine setDefault(State oldState, Action action, State newState)
      Set the default transition and action for a state. This transition will be used if no more specific transition was defined for the actual input. Repeated calls to this method simply change the default. This method can only be called before done(). An attempt to call it after done() results in an IllegalStateException.

    • setDefault

      public StateEngine setDefault(State oldState, State newState)
      Equivalent to setDefault( oldState, act, newState ) where act is an action that does nothing.

    • setDefault

      public StateEngine setDefault(State oldState)
      Euaivalent to setDefault( oldState, oldState )

    • done

      public void done()
      Called after all transitions have been added to the state engine. This provides an opportunity for the implementation to optimize its representation before the state engine is used. This method may only be called once. An attempt to call it more than once results in an IllegalStateException.

      Note that a valid StateEngine must satisfy the following conditions:

      1. It must contain exactly one state with Kind INITIAL.
      2. No final state may have an outgoing transition.
      If either of these conditions are violated, done() throws an IllegalStateException.

    • setDefaultAction

      public void setDefaultAction(Action act)
      Set the default action used in this state engine. This is the action that is called whenever there is no applicable transition. Normally this would simply flag an error. This method can only be called before done(). An attempt to call it after done() results in an IllegalStateException.

    • doIt

      public void doIt(Runner runner, Input in, boolean debug)
      Actually perform a state transition on the FSM on the runner.peek() FSM under Input in.

    • getDefaultNextState

      private State getDefaultNextState(State currentState)

    • getDefaultAction

      private Action getDefaultAction(State currentState)

    • innerDoIt

      private void innerDoIt(Runner runner, Input in, boolean debug)

    • performStateTransition

      void performStateTransition(Runner runner, Input in, State nextState, Action action, boolean debug)

    • mustBeInitializing

      private void mustBeInitializing()

    • mustNotBeInitializing

      private void mustNotBeInitializing()