2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
4 * The contents of this file are subject to the terms of either the GNU
5 * General Public License Version 2 only ("GPL") or the Common
6 * Development and Distribution License("CDDL") (collectively, the
7 * "License"). You may not use this file except in compliance with the
8 * License. You can obtain a copy of the License at
9 * http://www.netbeans.org/cddl-gplv2.html
10 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
11 * specific language governing permissions and limitations under the
12 * License. When distributing the software, include this License Header
13 * Notice in each file and include the License file at
14 * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
15 * particular file as subject to the "Classpath" exception as provided
16 * by Sun in the GPL Version 2 section of the License file that
17 * accompanied this code. If applicable, add the following below the
18 * License Header, with the fields enclosed by brackets [] replaced by
19 * your own identifying information:
20 * "Portions Copyrighted [year] [name of copyright owner]"
24 * Portions Copyrighted 2009 Jaroslav Tulach
27 package cz.xelfi.quoridor;
29 import cz.xelfi.quoridor.Player.Direction;
30 import java.io.BufferedReader;
31 import java.io.EOFException;
32 import java.io.IOException;
33 import java.io.Reader;
34 import java.io.StringReader;
35 import java.io.StringWriter;
36 import java.io.Writer;
37 import java.util.ArrayList;
38 import java.util.Arrays;
39 import java.util.BitSet;
40 import java.util.Collection;
41 import java.util.Collections;
42 import java.util.HashSet;
43 import java.util.List;
45 import java.util.regex.Matcher;
46 import java.util.regex.Pattern;
49 * Represents a snapshot of the game position,
50 * including all the placed and not-yet placed fences and player positions.
51 * It it can print itself to stream in
52 * <a href="http://www.gamerz.net/pbmserv/quoridor.html">ascii art format<a/>
53 * and can it read back. The class is immutable
54 * but it contains {@link #apply(cz.xelfi.quoridor.Move)}
55 * that produce new {@link Board} with position created after
56 * applying some {@link Move}. Use:
58 * Board whiteOnTurn = Board.empty();
59 * Board blackOnTurn = whiteOnTurn.apply(Move.NORTH);
60 * Board whiteAgain = blackOnTurn.apply(Move.SOUTH);
61 * Board withOneFence = whiteAgain.apply(Move.fence('D', 7));
64 * @author Jaroslav Tulach
66 public final class Board {
68 private final List<Player> players;
69 /** fences placed on board */
70 private final Set<Fence> fences;
71 /** occurpied bits (coordinates encoded by toIndex methods)
74 +-----------------------------------+
92 +-----------------------------------+
93 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
96 * even indexes == position of the pawns
97 * odd indexes == centers of fences
98 * even x odd == side of a fence
99 * odd x even == side of a fence
101 private final BitSet occupied;
102 /** which player's turn is next? */
103 private final int turn;
106 * Creates a new instance of Board
108 private Board (int x1, int y1, int f1, int x2, int y2, int f2) {
109 this.players = Collections.unmodifiableList (Arrays.asList (new Player[] {
110 new Player (x1, y1, f1, Player.Direction.NORTH),
111 new Player (x2, y2, f2, Player.Direction.SOUTH),
113 this.fences = Collections.emptySet ();
115 this.occupied = computeOccupied (players, fences);
116 } catch (IllegalPositionException ex) {
117 throw new IllegalStateException (ex.getMessage ());
122 /** Copy constructor that provides players and fences.
124 private Board (int turn, List<Player> players, Set<Fence> fences)
125 throws IllegalPositionException {
126 this.players = Collections.unmodifiableList (players);
127 this.fences = Collections.unmodifiableSet (fences);
128 this.occupied = computeOccupied (players, fences);
130 for (Player p : players) {
131 if (!accessibleFinalLine (p, p.endDirection, occupied, new BitSet ())) {
132 throw new IllegalPositionException ("Player " + p + " cannot reach " + p.endDirection + " side"); // NOI18N
135 this.turn = turn % players.size();
138 /** Returns empty board with default starting position.
139 * @return board with two pawns.
141 public static Board empty () {
142 return new Board (8, 0, 10, 8, 16, 10);
145 /** Returns players in the game.
146 * @return player object
148 public List<Player> getPlayers () {
152 /** The fences currently on board.
154 * @return immutable set of Fences
156 public Set<Fence> getFences () {
160 /** The player that is supposed to play now.
161 * @return the player to do next move
163 public Player getCurrentPlayer() {
164 return players.get(turn);
167 /** The play who wins on current board.
169 * @return the winning player or <code>null</code>
171 public Player getWinner() {
172 for (Player p : players) {
173 if (p.endDirection.reached(p)) {
180 /** Applies given move to current board.
182 * @param move move creates by one of the factory methods or fields of the {@link Move} class
183 * @return new board derived from this one
185 * @throws cz.xelfi.quoridor.IllegalPositionException throws exception if the move is illegal
187 public Board apply(Move move) throws IllegalPositionException {
188 if (getWinner() != null) {
189 throw new IllegalPositionException("Game finished!"); // NOI18N
192 if (move.direction != null) {
193 return move(getCurrentPlayer(), move.direction);
195 return fence(getCurrentPlayer(), move.fence);
199 /** Can the move be applied to current board position?
201 * @param move the move to apply
202 * @return true if one can call {@link #apply} method without getting
205 public boolean isApplicable(Move move) {
207 // trivial implementation is enough for now
210 } catch (IllegalPositionException ex) {
215 /** Moves the player in given direction. The direction usually
216 * is one of Player.Direction constants, but in case the move
217 * is a jump over another players pawn it can be followed by
218 * another (usually, if there is no fence the same) direction.
220 * @param player the player to move
221 * @param where one or two directions saying where
222 * @return the new board
223 * @exception IllegalPositionException if the move is not possible
225 final Board move (Player player, Player.Direction... where) throws IllegalPositionException {
226 if (where.length != 1 && where.length != 2) {
227 throw new IllegalPositionException ("Move over one or two Directions"); // NOI18N
230 int index = players.indexOf (player);
231 Player[] arr = players.toArray (new Player[0]);
233 Player oneStep = newPosition (player, where[0]);
235 if (where.length == 1) {
236 arr[index] = oneStep;
237 return new Board(turn + 1, Arrays.asList (arr), fences);
240 // straight jump over
241 for (Player p : players) {
242 if (p.getXInternal () == oneStep.getXInternal () && p.getYInternal() == oneStep.getYInternal ()) {
243 // ok, we are jumping over this one
244 GO_ON: if (where[0] != where[1]) {
245 // first of all ensure that we cannot go straight
247 newPosition (oneStep, where[0]);
248 } catch (IllegalPositionException ex) {
252 throw new IllegalPositionException ("You have to jump straight if there is no wall"); // NOI18N
254 arr[index] = newPosition (oneStep, where[1]);
255 return new Board (turn + 1, Arrays.asList (arr), fences);
258 throw new IllegalPositionException ("Cannot use multi direction when there is not oponent pawn"); // NOI18N
261 final Board fence (Player player, char x, int y, Fence.Orientation orientation) throws IllegalPositionException {
262 return fence(player, new Fence ((x - 'A') * 2 + 1, y * 2 - 1, orientation));
265 private void columnLine(int width, int spaceX, Writer w) throws IOException {
267 for (int x = 0; x < width - 1; x++) {
268 if (x % (spaceX + 1) == 0 && x > 0) {
270 ch = (char) (ch + 1);
277 private Board fence(Player player, Fence fence) throws IllegalPositionException {
278 if (player.getFences () == 0) {
279 throw new IllegalPositionException ("Not enough fences: " + player); // NOI18N
282 int index = players.indexOf (player);
283 Player[] arr = players.toArray (new Player[0]);
284 arr[index] = new Player (arr[index].getXInternal(), arr[index].getYInternal(), arr[index].getFences() - 1, arr[index].endDirection);
286 HashSet<Fence> fen = new HashSet<Fence> (this.fences);
289 return new Board (turn + 1, Arrays.asList (arr), fen);
296 private static final Pattern northSouthPattern = Pattern.compile("(\\+(\\|*)(\\*)?-+\\+)");
298 /** Reads the board from a reader. Opposite operation to {@link #write(java.io.Writer)}.
300 * @param r the reader
301 * @return the read board
302 * @throws IOException if I/O error occurs
303 * @throws IllegalPositionException if the reader does not contain description
306 public static Board read(Reader r) throws IOException, IllegalPositionException {
307 BufferedReader b = new BufferedReader(r);
309 String s = b.readLine();
311 throw new IOException("No board found!");
313 Matcher m = northSouthPattern.matcher(s);
315 return readFromBetween(b, m);
320 /** Translates the string into board, if possible. String created by
321 * use of {@link #toString()} is accepted, more information about the
322 * format is avaliable in the description of {@link #write(java.io.Writer)}
325 * @param board string to analyze
326 * @return board object, if the string can be read
327 * @throws IllegalPositionException if the string does not represent the board
329 public static Board valueOf(String board) throws IllegalPositionException {
331 return read(new StringReader(board));
332 } catch (IOException ex) {
333 // shall not happen, StringReader does not throw IOException
334 throw (IllegalPositionException)new IllegalPositionException(ex.getMessage()).initCause(ex);
338 private static int assertChar(String s, int pos, char... ch) throws IOException {
339 if (s.length() >= pos) {
340 for (int i = 0; i < ch.length; i++) {
341 if (ch[i] == s.charAt(pos)) {
346 throw new IOException("Not found " + ch[0] + " at " + pos + " in" + s);
349 private static Player findPlayer(
350 Player previous, String line, int y, int spaceX, Player.Direction dir, int fences
352 int index = line.indexOf(dir.player);
356 int x = (index - 1) / (spaceX + 1) * 2;
357 return new Player(x, y - 1, fences, dir);
360 private static Board readFromBetween(BufferedReader b, Matcher firstMatcher)
361 throws IOException, IllegalPositionException {
362 final int from = firstMatcher.start(1);
363 final int to = firstMatcher.end(1);
364 final int northFences = firstMatcher.end(2) - firstMatcher.start(2);
365 final int spaceX = (to - from - 1) / 9 - 1;
366 final int spaceY = 1;
370 Set<Fence> fences = new HashSet<Fence>();
372 StringBuffer sb = new StringBuffer();
374 for (int y = (spaceY + 1) * 9 - 1; y > 0; y--) {
375 String s = b.readLine();
377 throw new EOFException();
381 if (s.length() < to) {
382 throw new IOException("Too short line: " + s); // NOI18N
384 assertChar(s, from, '|');
385 assertChar(s, to - 1, '|');
387 if (y % (spaceY + 1) == 0) {
388 for (int x = 1; x < 9; x++) {
389 switch (assertChar(s, from + (spaceX + 1) * x, '+', '-', '|')) {
391 fences.add(new Fence(x * 2 - 1, row * 2 + 1, Fence.Orientation.HORIZONTAL));
394 fences.add(new Fence(x * 2 - 1, row * 2 + 1, Fence.Orientation.VERTICAL));
404 String line = s.substring(from, to);
405 p = findPlayer(p, line, y, spaceX, Player.Direction.NORTH, -1);
406 q = findPlayer(q, line, y, spaceX, Player.Direction.SOUTH, northFences);
410 String last = b.readLine();
412 throw new EOFException();
414 Matcher lastMatcher = northSouthPattern.matcher(last);
415 if (!lastMatcher.find()) {
416 throw new IOException("Unrecognized last line: " + last);
419 List<Player> arr = new ArrayList<Player>(2);
421 int southFences = lastMatcher.end(2) - lastMatcher.start(2);
422 arr.add(new Player(p.getXInternal(), p.getYInternal(), southFences, p.endDirection));
424 int turn = "*".equals(lastMatcher.group(3)) ? 0 : 1; // NOI18N
425 return new Board(turn, arr, fences);
430 /** Writes the board to the provided writer. <b>P</b> denotes position
431 * of the first player and <b>Q</b> of the second. Number of remaining
432 * fences of each player are shown in left bottom and left top corner
433 * as appropriate number of <b>|||</b> - one <b>|</b> per fence. The
434 * player that is supposed to move in this turn has <b>*</b> right after
435 * the set of its fences.
442 +|||||------------------------------+
444 8--| + + + + + + + + |--8
446 7--| + | + +-------+-------+ |--7
448 6--|-------+-------|-------+-------+ |--6
450 5--| + + + + + + + + |--5
452 4--| + + + | + + +-------|--4
454 3--| + + + +-------+ + + |--3
456 2--| + + + + + + + + |--2
458 1--| + + + + + | + + |--1
460 +|||*-------------------------------+
466 * @param w writer to write the board to
467 * @exception IOException if communiction with writer fails
469 public void write (Writer w) throws IOException {
473 private void northSouthSign(int width, char sign, Writer w) throws IOException {
474 int middle = width / 2;
475 for (int x = 0; x < width; x++) {
477 if (x == middle - 1) {
483 if (x == middle + 1) {
488 w.write(System.getProperty("line.separator")); // NOI18N
491 private void subColumnLine(int width, int spaceX, Writer w) throws IOException {
492 for (int x = 0; x < width - 1; x++) {
493 if (x % (spaceX + 1) == 0 && x > 0) {
501 /** This will print the board with provided spacing.
502 * This is example of 3:1 spacing:
508 * and this 4:2 spacing:
516 private void write (Writer w, int spaceX, int spaceY) throws IOException {
517 int width = spaceX * 9 + 10;
518 int height = spaceY * 9 + 10;
519 char[][] desk = new char[height][];
520 for (int i = 0; i < height; i++) {
521 desk[i] = new char[width];
522 for (int j = 0; j < width; j++) {
523 if (i % (spaceY + 1) == 0 && j % (spaceX + 1) == 0) {
530 desk[i][width - 1] = '|';
532 for (int i = 1; i < width - 1; i++) {
534 desk[height -1][i] = '-';
537 desk[0][width - 1] = '+';
538 desk[height - 1][0] = '+';
539 desk[height - 1][width - 1] = '+';
542 for (Player p : players) {
543 int px = p.getXInternal() / 2;
544 int py = p.getYInternal() / 2;
546 [1 + py * (spaceY + 1) + spaceY / 2]
547 [1 + px * (spaceX + 1) + spaceX / 2] = p.endDirection.player;
548 paintLeftFences(desk, p.endDirection, p.getFences(), p.equals(getCurrentPlayer()));
552 for (Fence f : fences) {
553 int fx = (f.getX() / 2 + 1) * (spaceX + 1);
554 int fy = (f.getY() / 2 + 1) * (spaceY + 1);
555 switch (f.getOrientation()) {
557 for (int i = -spaceX; i <= spaceX; i++) {
558 desk[fy][fx + i] = '-';
562 for (int i = -spaceY; i <= spaceY; i++) {
563 desk[fy + i][fx] = '|';
567 throw new IllegalStateException ("Unknown orientation: " + f.getOrientation ()); // NOI18N
571 northSouthSign(width, 'N', w);
572 w.write(System.getProperty("line.separator")); // NOI18N
574 columnLine(width, spaceX, w);
575 w.write(System.getProperty("line.separator")); // NOI18N
577 subColumnLine(width, spaceX, w);
578 w.write(System.getProperty("line.separator")); // NOI18N
580 for (int y = height - 1; y >= 0; y--) {
581 if (y == height / 2) {
586 boolean number = y % (spaceY + 1) == 0 && y > 0 && y < height - 1;
589 w.write(Integer.toString(cnt));
594 for (int x = 0; x < width; x++) {
599 w.write(Integer.toString(cnt));
603 if (y == height / 2) {
606 w.write(System.getProperty("line.separator")); // NOI18N
609 subColumnLine(width, spaceX, w);
610 w.write(System.getProperty("line.separator")); // NOI18N
612 columnLine(width, spaceX, w);
613 w.write(System.getProperty("line.separator")); // NOI18N
614 w.write(System.getProperty("line.separator")); // NOI18N
616 northSouthSign(width, 'S', w);
620 private void paintLeftFences(char[][] desk, Direction endDirection, int fences, boolean currentTurn) {
621 assert fences >= 0 && fences <= 10 : "Players: " + players;
622 switch (endDirection) {
624 for (int i = 0; i < fences; i++) {
625 desk[desk.length - 1][i + 1] = '|';
628 desk[desk.length - 1][fences + 1] = '*';
633 for (int i = 0; i < fences; i++) {
634 desk[0][i + 1] = '|';
637 desk[0][fences + 1] = '*';
653 public int hashCode () {
654 return occupied.hashCode ();
658 public boolean equals (Object o) {
659 if (o instanceof Board) {
661 return occupied.equals (b.occupied) && players.equals (b.players);
666 /** Converts the board into string representation. For more information
667 * about the format see {@link #write(java.io.Writer)}. To read the
668 * string back use {@link #valueOf(java.lang.String)}.
670 * @return string representing the board
673 public String toString() {
674 StringWriter w = new StringWriter();
677 } catch (IOException ex) {
678 return ex.toString();
685 // Validation methods
688 /** Computes new position of a player and checks whether there is no
689 * fence between the old and new.
691 private Player newPosition (Player old, Player.Direction direction) throws IllegalPositionException {
692 return newPosition (old, direction, occupied);
696 private static Player newPosition (Player old, Player.Direction direction, BitSet occupied) throws IllegalPositionException {
719 default: throw new IllegalStateException ("Unknown direction: " + direction); // NOI18N
722 if (nx < 0 || nx > 16) throw new IllegalPositionException ("Wrong player position: " + nx + ":" + ny); // NOI18N
723 if (ny < 0 || ny > 16) throw new IllegalPositionException ("Wrong player position: " + nx + ":" + ny); // NOI18N
725 int fenceIndex = toIndex (fx, fy);
726 if (occupied.get (fenceIndex)) {
727 throw new IllegalPositionException ("You cannot go over fences"); // NOI18N
730 return new Player (nx, ny, old.getFences (), old.endDirection);
733 /** @param position the current position of the player
734 * @param endDir the side the player wants to reach
735 * @param fences bits set to 1 when fences are placed
736 * @param reached bits on squares that were already reached (modified during run)
737 * @return true if the end line can be reached
739 private static boolean accessibleFinalLine (Player position, Player.Direction endDir, BitSet fences, BitSet reached) {
740 int index = toIndex (position);
741 if (reached.get (index)) {
742 // already visited without success
748 if (position.getYInternal() == 8) return true;
751 if (position.getYInternal() == 0) return true;
754 if (position.getXInternal() == 0) return true;
757 if (position.getXInternal() == 8) return true;
760 throw new IllegalStateException ("Wrong direction: " + endDir); // NOI18N
765 for (Player.Direction oneDirection : Player.Direction.values ()) {
767 if (accessibleFinalLine (newPosition (position, oneDirection, fences), endDir, fences, reached)) {
770 } catch (IllegalPositionException ex) {
778 /** Computes mask of the occupried bits.
780 private static BitSet computeOccupied (
781 Collection<Player> players, Collection<Fence> fences
782 ) throws IllegalPositionException {
783 BitSet occupied = new BitSet (20 * 30); // TBD this is just an upper guess
785 for (Player p : players) {
786 if (p.getXInternal() % 2 == 1) throw new IllegalPositionException ("Wrong player position: " + p); // NOI18N
787 if (p.getYInternal() % 2 == 1) throw new IllegalPositionException ("Wrong player position: " + p); // NOI18N
789 int index = toIndex (p);
790 if (occupied.get (index)) {
791 throw new IllegalPositionException ("There cannot be two players at " + p); // NOI18N
793 occupied.set (index);
796 for (Fence f : fences) {
798 for (int i = -1; i <= 1; i++) {
799 int index = toIndex (f, i);
800 if (index < 0 || index > occupied.size ()) {
801 throw new IllegalPositionException ("Wrong fence position: " + f); // NOI18N
803 if (occupied.get (index)) {
804 throw new IllegalPositionException ("Fence collition: " + f); // NOI18N
807 occupied.set (index);
815 /** Converts twodimensional coordinates of player to one dimensional index.
817 private static int toIndex (Player p) {
818 return toIndex (p.getXInternal(), p.getYInternal());
821 /** Converts twodimensional coordinates of fence to one dimensional index.
823 * @param whichPart (-1, 0, 1)
825 private static int toIndex (Fence f, int whichPart) {
829 switch (f.getOrientation ()) {
830 case HORIZONTAL: x += whichPart; break;
831 case VERTICAL: y += whichPart; break;
832 default: throw new IllegalStateException ("Wrong orientation: " + f.getOrientation ()); // NOI18N
835 return toIndex (x, y);
838 /** Diagonal conversion of two positive integers to one integer.
847 private static int toIndex (int x, int y) {
849 int baseOnY0 = max * (max + 1) / 2;