com.beasys.commerce.ebusiness.order
Class StateMachine

java.lang.Object
  com.beasys.commerce.ebusiness.order.StateMachine

All Implemented Interfaces

Serializable

public class StateMachine
extends Object
implements Serializable

A class for implementing finite state machines. The state machine is created by parsing an XML document, classes\orderstatus.xml.
The state machine helps get valid transitions based on a current transition, so that an Order Status can be moved to a valid new state.

See Also

Serialized Form

Constructor Summary

StateMachine(String domDocFile)
Constructor that takes as a parameter the name of an XML specification for the state machine.

Method Summary

String	getFirstState() Gets the first state an order can be set to, which should correspond to a SUBMITTED state.
String	getNextStateName(String currStateName, String event) Gets the state that results from sending a specified event to a specified state.
String[]	getValidEvents(String stateName) Gets the names of the events associated with transitions that lead from a specified state
String	handleEvent(Object targetObject, String currStateName, String event) Handles an event for a given object, in particular invokes the onExitMethod, onEntryMethod, and doMethod if they exists
static void	main(String[] argv) A testing 'main' that uses the classes\orderstatus.xml and show a tree of the possible transitions

Methods inherited from class java.lang.Object

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

Constructor Detail

StateMachine

public StateMachine(String domDocFile)
             throws Exception

Constructor that takes as a parameter the name of an XML specification for the state machine.

Parameters

domDocFile - The name of the XML file that has the state machine's specification, residing in the classpath

Throws

Exception

Method Detail

handleEvent

public String handleEvent(Object targetObject,
                          String currStateName,
                          String event)
                   throws StateTransitionException

Handles an event for a given object, in particular invokes the onExitMethod, onEntryMethod, and doMethod if they exists

Parameters

targetObject: - the target of the handling

currStateName: - based on the current state, decides on which action to take

event, - based on the event being handled, decides on which action to take

Returns

the new state the object has moved to.

Throws

StateTransitionException

getNextStateName

public String getNextStateName(String currStateName,
                               String event)
                        throws StateTransitionException

Gets the state that results from sending a specified event to a specified state.

Parameters

currStateName - The name of the current state

event - The event to be sent to the current state

Returns

The name of the new state

Throws

StateTransitionException

getValidEvents

public String[] getValidEvents(String stateName)

Gets the names of the events associated with transitions that lead from a specified state

Parameters

stateName, - the name of a state in the machine

Returns

an array of String, one per reachable events.

getFirstState

public String getFirstState()
                     throws StateTransitionException

Gets the first state an order can be set to, which should correspond to a SUBMITTED state.

Returns

the 'first' state, the source of transitions.

Throws

StateTransitionException

main

public static void main(String[] argv)

A testing 'main' that uses the classes\orderstatus.xml and show a tree of the possible transitions