level.java

这是我编写的第一个J2ME程序

/*
 * Copyright (c) 2002, 2003 Sun Microsystems, Inc. All Rights Reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * - Redistribution of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * - Redistribution in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Sun Microsystems, Inc., 'Java', 'Java'-based
 * names, or the names of contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * You acknowledge that this software is not designed, licensed or
 * intended for use in the design, construction, operation or maintenance
 * of any nuclear facility. $Id: Level.java,v 1.1 2003/05/16 00:16:01 zull Exp $
 */
package com.sun.j2me.blueprints.slugs.server;

import com.sun.j2me.blueprints.slugs.shared.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Vector;

/**
 * This class knows how to parse an ASCII level description.
 * Whitespace (leading and trailing blanks, tabs and comments
 * marked by '#') will be discarded during parsing. The number
 * of non-whitespace characters per line needs to be constant
 * across lines. Recognized characters are '.' (grass), '!'
 * (extra life), '*' (poison), '|' (wall), '^' (jet pack),
 * '>' (booster), 'v' (shovel) and '@' (house).
 */
public class Level {
    private int width;
    private int height;
    private Item[] objectData;

    /**
     * Construct a new instance from a level description
     * read from 'in'. During the initialization process
     * 'player_list' will be reset to values found in
     * the level description.
     */
    public Level(BufferedReader in, Player[] player_list) {
        String line;
        int c, i, line_length, x, y;
        List objects;

        y = 0;
        line_length = -1;
        objects = new Vector();

        for (i = 0; i < player_list.length; i++) {
            player_list[i].setX(-1);
            player_list[i].setY(-1);
            player_list[i].setDirection(Player.STILL);
        } 

        for (; ; ) {
            line = readLine(in);

            if (line == null) {
                break;
            } 

            if (line_length < 0) {
                line_length = line.length();
            } else if (line_length != line.length()) {
                throw new RuntimeException("all lines in map must have same length");
            } 

            for (x = 0; x < line_length; x++) {
                c = line.charAt(x);

                switch (c) {

                case '.':
                    objects.add(new Item(x, y, Item.GRASS));

                    break;

                case '!':
                    objects.add(new Item(x, y, Item.EXTRA_LIFE));

                    break;

                case '*':
                    objects.add(new Item(x, y, Item.POISON));

                    break;

                case '|':
                    objects.add(new Item(x, y, Item.WALL));

                    break;

                case '^':
                    objects.add(new Item(x, y, Item.JET_PACK));

                    break;

                case '>':
                    objects.add(new Item(x, y, Item.BOOSTER));

                    break;

                case 'v':
                    objects.add(new Item(x, y, Item.SHOVEL));

                    break;

                case '@':
                    objects.add(new Item(x, y, Item.HOUSE));

                    break;

                case '1':    // fall through

                case '2':
                    i = c - '1';

                    if (player_list[i].getX() >= 0 
                            || player_list[i].getY() >= 0) {
                        throw new RuntimeException("multiple definitions for player " 
                                                   + c);
                    } 

                    player_list[i].setX(x);
                    player_list[i].setY(y);

                    break;

                default:
                    throw new RuntimeException("unknown map character: " + c);
                }
            } 

            y++;
        } 

        for (i = 0; i < player_list.length; i++) {
            if (player_list[i].getX() < 0 || player_list[i].getY() < 0) {
                throw new RuntimeException("missing definition for player " 
                                           + (i + 1));
            } 
        } 

        width = line_length;
        height = y;
        objectData = new Item[objects.size()];

        ArrayList arrayList = new ArrayList(objects);

        objectData = (Item[]) arrayList.toArray(objectData);
    }

    /**
     * Return the width of the level in cells
     */
    public int getWidth() {
        return width;
    } 

    /**
     * Return the height of the level in cells
     */
    public int getHeight() {
        return height;
    } 

    /**
     * Return an item array with an item for each cell in the level
     */
    public Item[] getObjectData() {
        return objectData;
    } 

    private String readLine(BufferedReader in) {
        String line;
        int pound_index;

        for (; ; ) {
            try {
                line = in.readLine();
            } catch (IOException e) {
                return null;
            } 

            if (line == null) {
                return null;
            } 

            pound_index = line.indexOf('#');

            if (pound_index >= 0) {
                line = line.substring(0, pound_index);
            } 

            line = line.trim();

            if (line.length() == 0) {
                continue;
            } 

            return line;
        } 
    } 

}