praktikum-holons/src/classes/holonControlUnit/StateEstimator.java

package classes.holonControlUnit;

import java.util.ArrayList;
import java.util.HashMap;

import classes.Holon;
import classes.HolonElement;
import classes.holonControlUnit.messages.Message;
import classes.holonControlUnit.messages.StateMsg;
import classes.holonControlUnit.messages.StateRequestMsg;

/**
 * aggregates all states from sub holons and forwards the resulting own state to the state assembler
 * @author Jonas
 *
 */
public class StateEstimator {

	/* indicates the current state of the holon */
	public enum StateIndicator {
		/* everything runs as expected, all parameters are inside their tresholds */
		DESIRED, 
		/* everything is still as expected except for minor deviations, parts may be endangered/dysfunctional */
		ENDANGERED, 
		/* stability/functionality of holon is not guaranteed */
		DYSFUNCTIONAL
	}
	private final float POWER_TRESHOLD = 0.95f;
	
	private HolonControlUnit hcu;
	private StateIndicator stateInd;
	private float powerUsage;
	private HashMap<String, StateMsg> childStates;
	
	public StateEstimator(HolonControlUnit hcu) {
		this.hcu = hcu;
		this.stateInd = StateIndicator.DESIRED;
	}

	public StateIndicator getStateIndicator() {
		return stateInd;
	}
	
	/**
	 * Depth-first computation
	 * aggregates childrens state first, then computes own state
	 */
	public void computeState(int timeStep) {
		//request childrens state
		this.childStates = new HashMap<String, StateMsg>();
		ArrayList<String> children = this.hcu.getHierarchyController().getSubHolons();
		for(String child : children) {
			//send request to child
			this.hcu.getCommunicator().sendMsg(child, Message.Type.STATE_REQUEST, 
					this.hcu.getCommunicator().getGson().toJson(new StateRequestMsg(timeStep)));
		}
		//wait for sub holons to compute state and send it
		if(this.childStates.size() < children.size()) {
			System.err.println("Something went wrong while computing state of "+this.hcu.getHolon().getUniqueID());
			System.err.println("\tchildStates "+childStates);
			System.err.println("\tchildren "+children);
			return;
		}
		//aggregate cub holons state
		this.powerUsage = 0;
		for(String s : this.childStates.keySet()) {
			this.powerUsage += this.childStates.get(s).getPowerUsage();
		}
		//add state from holon elements
		Holon holon = this.hcu.getHolon();
		if(holon.isPhysical) {
			this.powerUsage += holon.getHolonObject().getEnergyAtTimeStep(timeStep);
		}
		if(this.powerUsage < this.POWER_TRESHOLD * this.hcu.getStateAssembler().getDesiredPowerUsage()) {
			this.stateInd = StateIndicator.DESIRED;
		} else {
			this.stateInd = StateIndicator.ENDANGERED;
		}
	}
	
	public void receiveState(String sender, StateMsg stateMsg) {
		if(this.childStates == null)
			return;
		this.childStates.put(sender, stateMsg);
	}
	
	public void receiveStateRequest(String sender, StateRequestMsg req) {
		computeState(req.getTimeStep());
		//send current state to sender/super holon
		StateMsg stateMsg = new StateMsg(this.powerUsage);
		String body = this.hcu.getCommunicator().getGson().toJson(stateMsg);
		this.hcu.getCommunicator().sendMsg(sender, Message.Type.STATE, body);
	}

	public float getPowerUsage() {
		return this.powerUsage;
	}
	
}