org.jboss.util.state

Class StateMachine

java.lang.Object

org.jboss.util.state.StateMachine

All Implemented Interfaces:

java.lang.Cloneable

public class StateMachine
extends java.lang.Object
implements java.lang.Cloneable

The representation of a finite state machine.

Version:

$Revision$

Field Summary

Fields

Modifier and Type	Field and Description
private State	currentState The current state of the state machine
private java.lang.String	description A description of the state machine
private static org.jboss.logging.Logger	log
private State	startState The starting state
private java.util.HashSet	states The set of states making up the state machine

Constructor Summary

Constructors

Constructor and Description
StateMachine(java.util.Set states, State startState) Create a state machine given its states and start state.
StateMachine(java.util.Set states, State startState, java.lang.String description) Create a state machine given its states and start state.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone() Make a copy of the StateMachine maintaining the current state.
State	getCurrentState() Get the current state of the state machine.
java.lang.String	getDescription() Get the state machine description.
State	getStartState() Get the start state of the state machine.
java.util.Set	getStates() Get the states of the state machine.
State	nextState(java.lang.String actionName) Transition to the next state given the name of a valid transition.
State	reset() Reset the state machine back to the start state
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

log

private static org.jboss.logging.Logger log

description

private java.lang.String description

A description of the state machine

states

private java.util.HashSet states

The set of states making up the state machine

startState

private State startState

The starting state

currentState

private State currentState

The current state of the state machine

Constructor Detail

StateMachine

public StateMachine(java.util.Set states,
                    State startState)

Create a state machine given its states and start state.

Parameters:

states - - Set for the state machine

startState - - the starting state

StateMachine

public StateMachine(java.util.Set states,
                    State startState,
                    java.lang.String description)

Create a state machine given its states and start state.

Parameters:

states - - Set for the state machine

startState - - the starting state

description - - an optional description of the state machine

Method Detail

clone

public java.lang.Object clone()

Make a copy of the StateMachine maintaining the current state.

Overrides:

clone in class java.lang.Object

Returns:

a copy of the StateMachine.

getDescription

public java.lang.String getDescription()

Get the state machine description.

Returns:

an possibly null description.

getCurrentState

public State getCurrentState()

Get the current state of the state machine.

Returns:

the current state.

getStartState

public State getStartState()

Get the start state of the state machine.

Returns:

the start state.

getStates

public java.util.Set getStates()

Get the states of the state machine.

Returns:

the machine states.

nextState

public State nextState(java.lang.String actionName)
                throws IllegalTransitionException

Transition to the next state given the name of a valid transition.

Parameters:

actionName - - the name of transition that is valid for the current state.

Returns:

the next state

Throws:

IllegalTransitionException

reset

public State reset()

Reset the state machine back to the start state

Returns:

the start state

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object