de.schildbach.game.BoardGeometry.java Source code

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Here is the source code for de.schildbach.game.BoardGeometry.java

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/*
 * Copyright 2001-2011 the original author or authors.
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.schildbach.game;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.NoSuchElementException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Board geometries are the only classes that are allowed to do arithmetic operations on game coordinates. All other
 * classes should never deal with specific coordinate subclasses.
 * <ul>
 * <li>there is only one board geometry instance for each type of board</li>
 * <li>board geometries serve as factories for their boards</li>
 * <li>the geometry knows about the notation of their coordinates</li>
 * <li>board geometries also serve as factories for their dedicated coordinates (allowing to share coordinate instances
 * between all games with the same geometry)</li>
 * </ul>
 * 
 * @author Andreas Schildbach
 */
public abstract class BoardGeometry {
    public static int instanceCount;

    protected static final Log LOG = LogFactory.getLog(BoardGeometry.class);

    private final Coordinate[] coordinates;

    protected BoardGeometry(int numCoordinates) {
        instanceCount++;
        coordinates = new Coordinate[numCoordinates];
    }

    private final transient Map<String, Coordinate> coordinateNotations = new LinkedHashMap<String, Coordinate>();

    protected final void putCoordinate(int key, Coordinate coordinate) {
        coordinateNotations.put(coordinate.getNotation(), coordinate);
        coordinates[key] = coordinate;
    }

    protected final Coordinate getCoordinate(int key) {
        return coordinates[key];
    }

    // interface:

    public final Board newBoard() {
        return new Board(new HashSet<Coordinate>(Arrays.asList(coordinates)));
    }

    public final Iterator<Coordinate> coordinateIterator() {
        return coordinateNotations.values().iterator();
    }

    protected Iterator<Coordinate> pieceIterator(final Board board, final int color) {
        final Iterator<Coordinate> boardIterator = this.coordinateIterator();
        return new Iterator<Coordinate>() {
            Coordinate next = null;

            public boolean hasNext() {
                if (next != null) {
                    return true;
                } else {
                    while (boardIterator.hasNext()) {
                        next = boardIterator.next();
                        Piece piece = board.getPiece(next);
                        if (piece != null && piece.getColor() == color)
                            return true;
                    }
                    next = null;
                    return false;
                }
            }

            public Coordinate next() {
                if (hasNext()) {
                    Coordinate result = next;
                    next = null;
                    return result;
                } else
                    throw new NoSuchElementException();
            }

            public void remove() {
                throw new UnsupportedOperationException();
            }
        };
    }

    public abstract boolean isValidCoordinate(Coordinate coordinate);

    /**
     * Locates a coordinate within this geometry.
     * 
     * @param notation
     *            notation of coordinate to locate
     * @return located coordinate or null if coordinate not found
     */
    public final Coordinate locateCoordinate(String notation) {
        return coordinateNotations.get(notation);
    }
}