info.gridworld.actor

Class Critter

java.lang.Object

info.gridworld.actor.Actor

info.gridworld.actor.Critter

public class Critter
extends Actor

A Critter is an actor that moves through its world, processing other actors in some way and then moving to a new location. Define your own critters by extending this class and overriding any methods of this class except for act. When you override these methods, be sure to preserve the postconditions.
The implementation of this class is testable on the AP CS A and AB exams.

Constructor Summary

Constructors

Constructor and Description
Critter()

Method Summary

Methods

Modifier and Type	Method and Description
void	act() A critter acts by getting a list of other actors, processing that list, getting locations to move to, selecting one of them, and moving to the selected location.
ArrayList<Actor>	getActors() Gets the actors for processing.
ArrayList<Location>	getMoveLocations() Gets a list of possible locations for the next move.
void	makeMove(Location loc) Moves this critter to the given location loc, or removes this critter from its grid if loc is null.
void	processActors(ArrayList<Actor> actors) Processes the elements of actors.
Location	selectMoveLocation(ArrayList<Location> locs) Selects the location for the next move.

Methods inherited from class info.gridworld.actor.Actor

getColor, getDirection, getGrid, getLocation, moveTo, putSelfInGrid, removeSelfFromGrid, setColor, setDirection, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Critter

public Critter()

Method Detail

act

public void act()

A critter acts by getting a list of other actors, processing that list, getting locations to move to, selecting one of them, and moving to the selected location.

Overrides:

act in class Actor

getActors

public ArrayList<Actor> getActors()

Gets the actors for processing. Implemented to return the actors that occupy neighboring grid locations. Override this method in subclasses to look elsewhere for actors to process.
Postcondition: The state of all actors is unchanged.

Returns:

a list of actors that this critter wishes to process.

processActors

public void processActors(ArrayList<Actor> actors)

Processes the elements of actors. New actors may be added to empty locations. Implemented to "eat" (i.e. remove) selected actors that are not rocks or critters. Override this method in subclasses to process actors in a different way.
Postcondition: (1) The state of all actors in the grid other than this critter and the elements of actors is unchanged. (2) The location of this critter is unchanged.

Parameters:

actors - the actors to be processed

getMoveLocations

public ArrayList<Location> getMoveLocations()

Gets a list of possible locations for the next move. These locations must be valid in the grid of this critter. Implemented to return the empty neighboring locations. Override this method in subclasses to look elsewhere for move locations.
Postcondition: The state of all actors is unchanged.

Returns:

a list of possible locations for the next move

selectMoveLocation

public Location selectMoveLocation(ArrayList<Location> locs)

Selects the location for the next move. Implemented to randomly pick one of the possible locations, or to return the current location if locs has size 0. Override this method in subclasses that have another mechanism for selecting the next move location.
Postcondition: (1) The returned location is an element of locs, this critter's current location, or null. (2) The state of all actors is unchanged.

Parameters:

locs - the possible locations for the next move

Returns:

the location that was selected for the next move.

makeMove

public void makeMove(Location loc)

Moves this critter to the given location loc, or removes this critter from its grid if loc is null. An actor may be added to the old location. If there is a different actor at location loc, that actor is removed from the grid. Override this method in subclasses that want to carry out other actions (for example, turning this critter or adding an occupant in its previous location).
Postcondition: (1) getLocation() == loc. (2) The state of all actors other than those at the old and new locations is unchanged.

Parameters:

loc - the location to move to