foodmaker.java

MVC设计模式早在面向对象语言Smalltalk-80中就被提出并在此后得到业界的广泛接受。它包括三类对象：（1）模型（Model）对象：是应用程序的主体部分。（2）视图（View）对象：是应用程序中

/********************************************************************************************/
/*                                                                                          */
/*                              FoodMaker.java                                              */
/*                                                                                          */
/*                                   果实建造线程，与蛇的运动独立                           */
/*                                                                                          */
/*                      Programed by Luo Pengkui on 2004-9                                  */
/*                                                                                          */
/********************************************************************************************/

import java.util.Observable;
import java.awt.Point;
import java.io.PrintStream;
import java.util.Calendar;
import java.util.Random;

//------------------------------------ BEGIN ------------------------------------------------

public class FoodMaker extends Observable implements Runnable
{

    private int m_amountofFoods;                                // 果实数量
    private FoodModel m_foods[];
    private MatrixModel m_matrix;
    private int m_raw;
    private int m_col;
    private boolean m_fruitAutoGrown;                           // 果实被吃后是否“立即”生成
    private Random m_rand;

    public static final int EMPTY = 0;                          // 格点的四种状态
    public static final int FRUIT = 1;
    public static final int SNAKE = 2;
    public static final int WALL  = 3;

    public FoodMaker( MatrixModel canvasMatrix )
    {
        m_matrix = canvasMatrix;
    }

    public void mb_start( int canvasCol, int canvasRow,         // 初始化果实建造器
        int amountofFoods, boolean fruitAutoGrown )
    {
        m_raw = canvasRow;
        m_col = canvasCol;
        m_amountofFoods = amountofFoods;
        m_fruitAutoGrown = fruitAutoGrown;
        m_foods = new FoodModel[m_amountofFoods];
        m_rand = new Random();

        for(int i = 0; i < m_amountofFoods; i++)                // 果实的初次建造
        {
            int x,y;
            m_foods[i] = mb_makeFood();
            do{
                x = m_rand.nextInt(m_col-1);                    // 位置为伪随机数
                y = m_rand.nextInt(m_raw-1);
            } while ( m_matrix.mb_getGridState(x,y) != EMPTY );

            Point position = new Point();
            position.setLocation( x,y );
            m_foods[i].mb_setPosition( position );
            m_matrix.mb_setGridState( x,y,FRUIT );
        }
        (new Thread( this )).start();                           // 开启果实复查建造线程

    }

    public FoodModel mb_makeFood()                              // 建造单个果实，随机设定生存期，用到Calendar类
    {
        Calendar rightNow = Calendar.getInstance();
        int seconds = rightNow.get(10) * 60 * 60 + rightNow.get(12) * 60 + rightNow.get(13);
        FoodModel food = new FoodModel();
        food.mb_setLife(7 + m_rand.nextInt(7));
        food.mb_setOverTime(seconds + food.mb_getLife());
        return food;
    }

    public FoodModel[] mb_getFoods()                            // 返回所有果实的引用，
    {                                                           // MainFrame中启动View监视器要用到
        return m_foods;
    }

    public void foodCheck()                                     // 检查果实是否“腐败”，重新生成之
    {                                                           // 现存果实的总量不变
        Calendar rightNow = Calendar.getInstance();
        int seconds = rightNow.get(10) * 60 * 60 + rightNow.get(12) * 60 + rightNow.get(13);
        m_rand = new Random();

        for(int i = 0; i < m_amountofFoods; i++)
        {

            int x = m_foods[i].mb_getPosition().x;
            int y = m_foods[i].mb_getPosition().y;
            if(( (m_foods[i].mb_getOverTime()<seconds) )
                || (m_matrix.mb_getGridState(x,y) != FRUIT ) )  // 如果果实“腐败”或者被蛇吃就重新生成
            {
                m_matrix.mb_setGridState( x,y,EMPTY );          // 释放原来果实所占格点

                m_foods[i] = mb_makeFood();
                do{
                   x = m_rand.nextInt(m_col);
                   y = m_rand.nextInt(m_raw);
                } while ( m_matrix.mb_getGridState(x,y) != EMPTY );// 只能在空的地方生成

                Point position = new Point();
                position.setLocation( x,y );
                m_foods[i].mb_setPosition( position );

                m_matrix.mb_setGridState( x,y,FRUIT );
            }
        }
        setChanged();                                           // Model通知View数据已经更新, in Class Observable
        notifyObservers();
    }

    public void run()                                           // 运行线程定期检查果实状态
    {
        do
        {
            foodCheck();
            try
            {
                Thread.sleep(100L);
            }
            catch(InterruptedException e)
            {
                System.out.println("Exception Message: ".concat(String.valueOf(e)));
            }
        } while(true);
    }
}

//------------------------------------- END -------------------------------------------------