AutoState.java

package StateMachine;

import java.util.ArrayList;
import java.util.prefs.Preferences;

public class AutoState {
	
	protected ArrayList<Action> actionList;
	protected ArrayList<Event> eventList;
	public String name;
	protected AutoState nextState;
	protected Preferences statePrefs;
	
	public AutoState() {
		this.name = "AutoState";
		
		actionList = new ArrayList<Action>();
		eventList = new ArrayList<Event>();
		this.nextState = null;
	}
	
	public AutoState(String name) {
		this.name = name;
		actionList = new ArrayList<Action>();
		eventList = new ArrayList<Event>();
		this.nextState = null;
	}
	
	// create auto state from preferences
	public AutoState(Preferences statePrefs) throws Exception {
		this.name = statePrefs.get("name","AutoState");
		
		actionList = new ArrayList<Action>();
		eventList = new ArrayList<Event>();
		
		this.nextState = null;
	}
	
	public void addAction(Action newAction) {
		actionList.add(newAction);
	}
	
	public void addEvent(Event newEvent) {
		eventList.add(newEvent);
	}
	
	public void associateNextState(AutoState nextState) {
		this.nextState = nextState;
	}
	
	// enter into state first time
	public void enter()
	{
		for (Action a: actionList) {
			// initialize each action
			a.initialize();
		}
		
		for (Event e: eventList) {
			// initialize each event for monitoring
			e.initialize();
		}
	}
	
	// called periodically
	public AutoState process()
	{
		// debug only - say who we are
		//System.out.println("Current state is " + name);
		
		// for all the actions this state has, process each
		for (Action a: actionList) {
			a.process();
		}
		
		// for all the events this state has, check each
		for (Event e: eventList) {
			// if any event is triggered
			if (e.isTriggered()) {
				
				// query for its next state, and go there
				return this.nextState;
			}
		}
		
		// if we reach the end and nothing has triggered, return this state
		return this;
	}
	
	// exit state 
	public void exit()
	{
		// for all the actions this state has, cleanup each
		for (Action a: actionList) {
			a.cleanup();
		}		
	}
	
	public void persistWrite(int counter, Preferences prefs) {

		// create node for autoState - done by the derived class
		Preferences statePrefs = prefs.node(counter + "_" + this.name);

		statePrefs.put("class",this.getClass().toString());
			
		// create nodes for actions and events
		Preferences actionPrefs = statePrefs.node("actions");
		Preferences eventPrefs = statePrefs.node("events");
				
		// store all the actions in the action prefs
		int ctr = 0;
		for (Action a: actionList)
		{
			a.persistWrite(ctr++, actionPrefs);
		}
		
		// store all the events in the action prefs
		ctr = 0;
		for (Event e: eventList)
		{
			e.persistWrite(ctr++, eventPrefs);
		}

	}
}