compoundtracker.java

一个基于PlaceLab的室内和室外的智能导航系统

package org.placelab.client.tracker;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

import org.placelab.core.Measurement;
import org.placelab.core.Types;

/**
 * A CompoundTracker encapsulates multiple {@link Tracker} objects
 * in a single Tracker.  
 * This is useful primarily for comparing multiple Trackers against
 * one another.  For instance, using a CompoundTracker with a
 * {@link org.placelab.demo.mapview.TrackedMapView} will produce multiple position reticles
 * on the map, one for each Tracker in the CompoundTracker. 
 */
public class CompoundTracker extends Tracker {
	private Vector trackers;
	
	public CompoundTracker() {
		trackers = new Vector();
	}

	/**
	 * Adds a {@link Tracker} to the CompoundTracker
	 * All trackers added will be forwarded all requests to
	 * update, either with or without Measurement.
	 * @param t the {@link Tracker} to add
	 */
	public void addTracker(Tracker t) {
		trackers.addElement(t);
	}
	
	/**
	 * Gets a Vector of all Trackers in this CompoundTracker
	 */
	public Vector getTrackers() {
		return trackers;
	}
	
	/**
	 * Removes all the Trackers from the CompoundTracker.  The Trackers
	 * will not be reset and may continue to be used elsewhere, but they
	 * will no longer be updated with by the CompoundTracker and their estimates
	 * will no longer be included in the CompoundTracker's {@link CompoundEstimate}
	 * results.
	 */
	public void clearTrackers() {
		trackers.removeAllElements();
	}

	Hashtable badAPs = new Hashtable();
	
	public void updateEstimateImpl(Measurement m) {
		for (Enumeration it = trackers.elements(); it.hasMoreElements();) {
			Tracker t = (Tracker)it.nextElement();
			t.updateEstimate(m);
		}
	}
	
	public Estimate getEstimate() {
		if (trackers.size() > 0) {
			Enumeration it = trackers.elements();
			Tracker t = (Tracker) it.nextElement();
			CompoundEstimate rv = new CompoundEstimate(t.getEstimate());
			while (it.hasMoreElements()) {
				t = (Tracker) it.nextElement();
				rv.addEstimate(t.getEstimate());
			}
			return rv;
		} else {
			return new CompoundEstimate(Types.newEstimate(0L,Types.newCoordinate(),"0.0"));
		}
	}

	public boolean acceptableMeasurement(Measurement m) {
		for (Enumeration it = trackers.elements(); it.hasMoreElements();) {
			Tracker t = (Tracker)it.nextElement();
			if (t.acceptableMeasurement(m)) {
				return true;
			}
		}
		return false;
	}

	public void updateWithoutMeasurement(long durationMillis) {
		for (Enumeration it = trackers.elements(); it.hasMoreElements();) {
			Tracker t = (Tracker)it.nextElement();
			t.updateWithoutMeasurement(durationMillis);
		}
	}

	public void resetImpl() {
		for (Enumeration it = trackers.elements(); it.hasMoreElements();) {
			Tracker t = (Tracker)it.nextElement();
			t.reset();
		}
	}
}