A case study - Objects First with Java: A Practical Introduction Using BlueJ - page 488

Code 14.1
continued
An outline of the
Vehicle class

public Location getLocation()
{

return location;

}

/**
* Set the current location.
* @param location Where it is. Must not be null.
* @throws NullPointerException If location is null.
*/
public void setLocation(Location location)
{

if (location != null ){
this .location = location;

}
else {
throw new NullPointerException();

}

}

/**
* @return Where this vehicle is currently headed, or
* null if it is idle.
*/
public Location getTargetLocation()
{

return targetLocation;

}

/**
* Set the required target location.
* @param location Where to go. Must not be null.
* @throws NullPointerException If location is null.
*/
public void setTargetLocation(Location location)
{

if (location != null ){
targetLocation = location;

}
else {
throw new NullPointerException();

}

}

/**
* Clear the target location.
*/