/**
* Look for rabbits adjacent to the current location. Only the first live rabbit is eaten.
*
* @return Where food was found, or null if it wasn't.
*/
private Location findFood() {
Field field = getField();
List<Location> adjacent = field.adjacentLocations(getLocation());
Iterator<Location> it = adjacent.iterator();
while (it.hasNext()) {
Location where = it.next();
Object animal = field.getObjectAt(where);
if (animal instanceof Rabbit) {
Rabbit rabbit = (Rabbit) animal;
if (rabbit.isAlive()) {
rabbit.setDead();
foodLevel = RABBIT_FOOD_VALUE;
// Remove the dead rabbit from the field.
return where;
}
}
if (animal instanceof Fox) {
Fox fox = (Fox) animal;
if (fox.isAlive()) {
fox.setDead();
foodLevel = WOLVES_FOOD_VALUE;
// Remove the dead rabbit from the field.
return where;
}
}
}
return null;
}
/**
* Run the simulation from its current state for a single step. Iterate over the whole field
* updating the state of each fox and rabbit.
*/
public void simulateOneStep() {
step++;
// Provide space for newborn rabbits.
List<Rabbit> newRabbits = new ArrayList<Rabbit>();
// Let all rabbits act.
for (Iterator<Rabbit> it = rabbits.iterator(); it.hasNext(); ) {
Rabbit rabbit = it.next();
rabbit.run(newRabbits);
if (!rabbit.isAlive()) {
it.remove();
}
}
// Provide space for newborn foxes.
List<Fox> newFoxes = new ArrayList<Fox>();
// Let all foxes act.
for (Iterator<Fox> it = foxes.iterator(); it.hasNext(); ) {
Fox fox = it.next();
fox.hunt(newFoxes);
if (!fox.isAlive()) {
it.remove();
}
}
// Add the newly born foxes and rabbits to the main lists.
rabbits.addAll(newRabbits);
foxes.addAll(newFoxes);
view.showStatus(step, field);
}