/* * AP(r) Computer Science GridWorld Case Study: * Copyright(c) 2005-2006 Cay S. Horstmann (http://horstmann.com) * * This code is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation. * * This code is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * @author Chris Nevison * @author Barbara Cloud Wells * @author Cay Horstmann */ import info.gridworld.actor.Actor; import info.gridworld.actor.Critter; import info.gridworld.grid.Grid; import info.gridworld.grid.Location; import java.awt.Color; import java.util.ArrayList; /** * A CrabCritter looks at a limited set of neighbors when it eats and moves. *
* This class is not tested on the AP CS A and AB exams. */ public class CrabCritter extends Critter { public CrabCritter() { setColor(Color.RED); } /** * A crab gets the actors in the three locations immediately in front, to its * front-right and to its front-left * @return a list of actors occupying these locations */ public ArrayList getActors() { ArrayList actors = new ArrayList(); int[] dirs = { Location.AHEAD, Location.HALF_LEFT, Location.HALF_RIGHT }; for (Location loc : getLocationsInDirections(dirs)) { Actor a = getGrid().get(loc); if (a != null) actors.add(a); } return actors; } /** * @return list of empty locations immediately to the right and to the left */ public ArrayList getMoveLocations() { ArrayList locs = new ArrayList(); int[] dirs = { Location.LEFT, Location.RIGHT }; for (Location loc : getLocationsInDirections(dirs)) if (getGrid().get(loc) == null) locs.add(loc); return locs; } /** * If the crab critter doesn't move, it randomly turns left or right. */ public void makeMove(Location loc) { if (loc.equals(getLocation())) { double r = Math.random(); int angle; if (r < 0.5) angle = Location.LEFT; else angle = Location.RIGHT; setDirection(getDirection() + angle); } else super.makeMove(loc); } /** * Finds the valid adjacent locations of this critter in different * directions. * @param directions - an array of directions (which are relative to the * current direction) * @return a set of valid locations that are neighbors of the current * location in the given directions */ public ArrayList getLocationsInDirections(int[] directions) { ArrayList locs = new ArrayList(); Grid gr = getGrid(); Location loc = getLocation(); for (int d : directions) { Location neighborLoc = loc.getAdjacentLocation(getDirection() + d); if (gr.isValid(neighborLoc)) locs.add(neighborLoc); } return locs; } }