/**
* Represents a fox.
*
* @author David Matuszek
* @version October 12, 2001
*/
public class Fox extends Animal {
// instance variables
private boolean haveSeenRabbit = false;
private boolean canSeeRabbitNow = false;
private int distanceToRabbit;
private int directionToRabbit;
private int currentDirection;
/**
* Constructs a Fox in the given model, at the given position
* in the field.
*
* @param model the model that controls this fox.
* @param row the row of the field containing this fox.
* @param column the column of the field containing this fox.
*/
public Fox(Model model, int row, int column) {
super(model, row, column);
currentDirection = Model.random(Model.MIN_DIRECTION,
Model.MAX_DIRECTION);
}
/**
* Controls the movement of the fox.
*
* @return the direction in which the fox wishes to move.
*/
int decideMove() {
// look all around for rabbit
canSeeRabbitNow = false;
for (int i = Model.MIN_DIRECTION; i <= Model.MAX_DIRECTION; i++) {
if (look(i) == Model.RABBIT) {
canSeeRabbitNow = haveSeenRabbit = true;
directionToRabbit = i;
distanceToRabbit = distance(i);
}
}
// if rabbit has been seen recently (not necessarily this time),
// move toward its last known position
if (haveSeenRabbit) {
if (distanceToRabbit > 0) {
distanceToRabbit–;
return directionToRabbit;
}
else { // rabbit was here–where did it go?
haveSeenRabbit = false;
currentDirection = Model.random(Model.MIN_DIRECTION,
Model.MAX_DIRECTION);
}
}
// either haven’t seen rabbit, or lost track of rabbit
// continue with current direction, maybe dodging bushes
if (canMove(currentDirection))
return currentDirection;
else if (canMove(Model.turn(currentDirection, 1)))
return Model.turn(currentDirection, 1);
else if (canMove(Model.turn(currentDirection, -1)))
return Model.turn(currentDirection, -1);
else {
currentDirection = Model.random(Model.MIN_DIRECTION,
Model.MAX_DIRECTION);
for (int i = 0; i < 8; i++) {
if (canMove(currentDirection))
return currentDirection;
else
currentDirection = Model.turn(currentDirection, 1);
}
}
// stuck! cannot move
return Model.STAY;
}
}