Updater.java

package org.usfirst.frc.team236.robot;

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;
/**
 * Takes care of updating all updatables that should update with the main robot thread,
 * as well as updatables that should run in their own separate thread.
 * 
 * This class cannot be instantiated externally, so call Updater.getInstance() to get
 * the instance of this class
 * @author team236
 *
 */
public class Updater {
	
	//the single instance of updater is held within the updater class
	static Updater updater;
	boolean controlLoopsStarted = false;

	//the list of all the things that can be updated
	ArrayList<Updatable> updatabales = new ArrayList<Updatable>();
	//the instance of the threadedUpdater class which updates all updatables that should
	//be updated in a separate thread.
	ThreadedUpdater threadedUpdater;
	ElevatorThreadedUpdater elev;
	
	//a private constructor means that a new instance of updater cannot be created
	//outside of this class
	private Updater(){
		//construct and start the threaded updater for control loops like PID/profile follower
		threadedUpdater = new ThreadedUpdater();
		elev = new ElevatorThreadedUpdater();
		
	}
	
	public void initControllers(){
		if(!controlLoopsStarted){
			Timer e_timer = new Timer();
			Timer timer = new Timer();
			timer.scheduleAtFixedRate(threadedUpdater, 0, 20);
			e_timer.scheduleAtFixedRate(elev, 0, 20);
		}
		controlLoopsStarted = true;
		
	}
	
	//this returns the single instance of updater
	//if the instance has not been created yet, a new one is made
	public static Updater getInstance(){
		if(updater == null){
			updater = new Updater();
		}
		return updater;
	}
	
	//iterate through the list of updatables, updating each
	public void updateAll(){
		for(int i = 0; i < updatabales.size(); i++){
			updatabales.get(i).update();
		}
	}
	
	//add a new updatable object to the list that will be updated.
	public void addUpdatable(Updatable updatable){
		updatabales.add(updatable);
	}
	
	//add a new updatable object to be run in a separate thread
	public void addThreadedUpdatable(Updatable updatable){
		threadedUpdater.addThreadedUpdatable(updatable);
	}
	
	public void addElevatorUpdater(Updatable updatable){
		elev.addThreadedUpdatable(updatable);
	}
	
	//class for threaded updates
	private class ThreadedUpdater extends TimerTask {
		//list of updatables that should run in their own thread
		ArrayList<Updatable> _50hz_updatables = new ArrayList<Updatable>();
		
		//add an updatable that will run in a separate thread
		public void addThreadedUpdatable(Updatable updatable){
			_50hz_updatables.add(updatable);
		}
		
		//method called automatically by the timer in Updater
		@Override
		public void run() {
			for(int i = 0; i < _50hz_updatables.size(); i++){
				_50hz_updatables.get(i).update();
			}	
		}
	}
	//class for threaded updates
		private class ElevatorThreadedUpdater extends TimerTask {
			//list of updatables that should run in their own thread
			ArrayList<Updatable> _50hz_updatables = new ArrayList<Updatable>();
			
			//add an updatable that will run in a separate thread
			public void addThreadedUpdatable(Updatable updatable){
				_50hz_updatables.add(updatable);
			}
			
			//method called automatically by the timer in Updater
			@Override
			public void run() {
				for(int i = 0; i < _50hz_updatables.size(); i++){
					_50hz_updatables.get(i).update();
				}	
			}
		}
}