org.jboss.com.sun.corba.se.spi.orbutil.fsm

Class FSMImpl

java.lang.Object

org.jboss.com.sun.corba.se.spi.orbutil.fsm.FSMImpl

All Implemented Interfaces:

FSM

Direct Known Subclasses:

AOMEntry

public class FSMImpl
extends Object
implements FSM

This is the main class that represents an instance of a state machine using a state engine. It may be used as a base class, in which case the guards and actions have access to the derived class.

Author:

Ken Cavanaugh

Constructor Summary

Constructors

Constructor and Description
FSMImpl(StateEngine se, State startState) Create an instance of an FSM using the StateEngine in a particular start state.
FSMImpl(StateEngine se, State startState, boolean debug)

Method Summary

Methods

Modifier and Type	Method and Description
void	doIt(Input in) Perform the transition for the given input in the current state.
State	getState() Return the current state.
void	internalSetState(State nextState)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FSMImpl

public FSMImpl(StateEngine se,
       State startState)

Create an instance of an FSM using the StateEngine in a particular start state.

FSMImpl

public FSMImpl(StateEngine se,
       State startState,
       boolean debug)

Method Detail

getState

public State getState()

Return the current state.

Specified by:

getState in interface FSM

doIt

public void doIt(Input in)

Perform the transition for the given input in the current state. This proceeds as follows:

Let S be the current state of the FSM. If there are guarded actions for S with input in, evaluate their guards successively until all have been evaluted, or one returns a non-DISABLED Result.

1. If a DEFERED result is returned, retry the input
2. If a ENABLED result is returned, the action for the guarded action is the current action
3. Otherwise there is no enabled action. If S has a default action and next state, use them; otherwise use the state engine default action (the next state is always the current state).

After the action is available, the transition proceeds as follows:

1. If the next state is not the current state, execute the current state postAction method.
2. Execute the action.
3. If the next state is not the current state, execute the next state preAction method.
4. Set the current state to the next state.

Specified by:

doIt in interface FSM

internalSetState

public void internalSetState(State nextState)