item.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: Item.java,v 1.1 2003/05/16 00:16:02 zull Exp $
 */
package com.sun.j2me.blueprints.slugs.shared;

/**
 * This class represents a state change in the
 * game engine. Because this class extends Data,
 * instances can easily be converted from and to
 * integer arrays for communicating them over sockets.
 */
public class Item extends Data {
    // object types
    public static final int JET_PACK = 0;
    public static final int SHOVEL = 1;
    public static final int BOOSTER = 2;
    public static final int EXTRA_LIFE = 3;
    public static final int POISON = 4;
    public static final int WALL = 5;
    public static final int HOUSE = 6;
    public static final int PATH1 = 7;
    public static final int PATH2 = 8;
    public static final int GRASS = 9;
    public static final int DELETE = 10;
    public static final int JETPACK_COUNT = 11;
    public static final int SHOVEL_COUNT = 12;
    public static final int LIFE_COUNT = 13;
    // game status
    public static final int NEW_LEVEL = 14;
    private static final String[] OBJECT_TYPE_STRING = {
        "jetpack", "shovel", "booster", "extra_life", "poison", "wall", 
        "house"
    };
    private static final int X = 0;
    private static final int Y = 1;
    private static final int STATUS = 2;
    private static final int SIZE = 3;
    private boolean dirty;

    /**
     * Construct a new instance from an
     * ('x', 'y') coordinate and a status
     * indicator.
     */
    public Item(int x, int y, int status) {
        buf = new int[SIZE];

        setX(x);
        setY(y);
        setStatus(status);
    }

    /**
     * Parse 'string' and return the numeric status
     * for it. Will throw a RuntimeException for
     * unrecognized types.
     */
    public static int getStatusTypeForString(String string) {
        for (int i = 0; i < OBJECT_TYPE_STRING.length; i++) {
            if (string.equals(OBJECT_TYPE_STRING[i])) {
                return i;
            } 
        } 

        throw new RuntimeException("invalid type");
    } 

    /**
     * Initialize this instance from 'item'
     */
    public void copyFrom(Item item) {
        setX(item.getX());
        setY(item.getY());
        setStatus(item.getStatus());
    } 

    /**
     * Return the x attribute of this instance
     */
    public int getX() {
        return buf[X];
    } 

    /**
     * Return the y attribute of this instance
     */
    public int getY() {
        return buf[Y];
    } 

    /**
     * Return the status attribute of this instance
     */
    public int getStatus() {
        return buf[STATUS];
    } 

    /**
     * Return the status attribute of this instance
     * as a string
     */
    public String getStatusString() {
        int status = getStatus();

        return status >= JET_PACK && status <= PATH2 
               ? OBJECT_TYPE_STRING[status] : "" + status;
    } 

    /**
     * Returns 'true' if this instance has been modified
     * since the last call to setDirty(false), 'false'
     * otherwise
     */
    public boolean isDirty() {
        return dirty;
    } 

    /**
     * Set the x attribute of this instance to 'x'
     */
    public void setX(int x) {
        if (x == buf[X]) {
            return;
        } 

        buf[X] = x;
        dirty = true;
    } 

    /**
     * Set the y attribute of this instance to 'x'
     */
    public void setY(int y) {
        if (y == buf[Y]) {
            return;
        } 

        buf[Y] = y;
        dirty = true;
    } 

    /**
     * Set the 'status' attribute of this instance to 'x'
     */
    public void setStatus(int status) {
        if (status == buf[STATUS]) {
            return;
        } 

        buf[STATUS] = status;
        dirty = true;
    } 

    /**
     * Marks this instance as dirty when 'x' is true,
     * as clean otherwise
     */
    public void setDirty(boolean x) {
        dirty = x;
    } 

    /**
     * Return the size of this particular Data subtype
     */
    public static int getSize() {
        return SIZE;
    } 

    /**
     * Return a string representation of this instance
     */
    public String toString() {
        return "x = " + getX() + ", y = " + getY() + ", status = " 
               + getStatusString();
    } 

}