Page 258 - The Definitive Guide to Building Java Robots

Preston_5564C07.fm Page 239 Monday, September 26, 2005 5:38 AM

CHAPTER 7 ■ NAVIGATION 239

the robot will want to make. Its child class, DistanceVector, is used to help the programmer
differentiate between moving with units of distance or units of time.
The two public fields are heading and magnitude. The heading I chose to be an int for
degrees and the magnitude can be any double value. See Example 7-8.

Example 7-8. MotionVector

package com.scottpreston.javarobot.chapter7;

public class MotionVector extends Edge{

public int heading = 0;
public double magnitude = 0;

public MotionVector(int h, double seconds) {
heading = h;
magnitude = seconds;
weight= (int)seconds;
}

public MotionVector(String h, String seconds) throws Exception {
heading = new Integer(h).intValue();
magnitude = new Double(seconds).doubleValue();
weight= (int)magnitude;
}

public String toString() {
return "Heading: " + heading + " Seconds: " + magnitude;
}
}
The next class, DistanceVector, is basically the same as the MotionVector except that in
this navigation class I convert inches to seconds via a conversion based on a calibration of the
robot’s speed and surface. See Example 7-9.

Example 7-9. DistanceVector

package com.scottpreston.javarobot.chapter7;

public class DistanceVector extends MotionVector {

public DistanceVector(int h, double inches) {
super(h, inches);
}