package com.zc.manythread;import javax.swing.JOptionPane;/*一共有５个进程需要请求资源，有３类资源*/public class Bank {    // 每个进程所需要的最大资源数    public static int MAX[][] = { { 7, 5, 3 }, { 3, 2, 2 }, { 9, 0, 2 },            { 2, 2, 2 }, { 4, 3, 3 } };    // 系统拥有的初始资源数    public static int AVAILABLE[] = { 10, 5, 7 };    // 系统已给每个进程分配的资源数    public static int ALLOCATION[][] = { { 0, 0, 0 }, { 0, 0, 0 }, { 0, 0, 0 },            { 0, 0, 0 }, { 0, 0, 0 } };    // 每个进程还需要的资源数    public static int NEED[][] = { { 7, 5, 3 }, { 3, 2, 2 }, { 9, 0, 2 },            { 2, 2, 2 }, { 4, 3, 3 } };    // 每次申请的资源数    public static int Request[] = { 0, 0, 0 };    // 进程数与资源数    public static int M = 5, N = 3;    int FALSE = 0;    int TRUE = 1;    public void showdata() {        int i, j;        System.out.print("系统可用的资源数为:/n");        for (j = 0; j < N; j++) {            System.out.print("资源" + j + ":" + AVAILABLE[j] + " ");        }        System.out.println();        System.out.println("各进程还需要的资源量:");        for (i = 0; i < M; i++) {            System.out.print("进程" + i + ":");            for (j = 0; j < N; j++) {                System.out.print("资源" + j + ":" + NEED[i][j] + " ");            }            System.out.print("/n");        }        System.out.print("各进程已经得到的资源量: /n");        for (i = 0; i < M; i++) {            System.out.print("进程");            System.out.print(i);            for (j = 0; j < N; j++) {                System.out.print("资源" + j + ":" + ALLOCATION[i][j] + " ");            }            System.out.print("/n");        }    }    // 分配资源，并重新更新各种状态    public void changdata(int k) {        int j;        for (j = 0; j < N; j++) {            AVAILABLE[j] = AVAILABLE[j] - Request[j];            ALLOCATION[k][j] = ALLOCATION[k][j] + Request[j];            NEED[k][j] = NEED[k][j] - Request[j];        }    };    // 回收资源，并重新更新各种状态    public void rstordata(int k) {        int j;        for (j = 0; j < N; j++) {            AVAILABLE[j] = AVAILABLE[j] + Request[j];            ALLOCATION[k][j] = ALLOCATION[k][j] - Request[j];            NEED[k][j] = NEED[k][j] + Request[j];        }    };    // 释放资源    public void free(int k) {        for (int j = 0; j < N; j++) {            AVAILABLE[j] = AVAILABLE[j] + ALLOCATION[k][j];            System.out.print("释放" + k + "号进程的" + j + "资源!/n");        }    }    public int check0(int k) {        int j, n = 0;        for (j = 0; j < N; j++) {            if (NEED[k][j] == 0)                n++;        }        if (n == 3)            return 1;        else            return 0;    }    // 检查安全性函数    public int chkerr(int s) {        int WORK;        int FINISH[] = new int[M], temp[] = new int[M];// 保存临时的安全进程序列        int i, j, k = 0;        for (i = 0; i < M; i++)            FINISH[i] = FALSE;        for (j = 0; j < N; j++) {            WORK = AVAILABLE[j]; // 第j个资源可用数            i = s;            // 判断第i个进程是否满足条件            while (i < M) {                if (FINISH[i] == FALSE && NEED[i][j] <= WORK) {                    WORK = WORK + ALLOCATION[i][j];                    FINISH[i] = TRUE;                    temp[k] = i;                    k++;                    i = 0;                } else {                    i++;                }            }            for (i = 0; i < M; i++)                if (FINISH[i] == FALSE) {                    System.out.print("/n系统不安全!!! 本次资源申请不成功!/n");                    return 1;                }        }        System.out.print("/n经安全性检查，系统安全，本次分配成功。/n");        System.out.print("本次安全序列：");        for (i = 0; i < M - 1; i++) {            System.out.print("进程" + temp[i] + "->");        }        System.out.print("进程" + temp[M - 1]);        System.out.println("/n");        return 0;    }    /**     * @param args     */    public static void main(String[] args) {        int i = 0, j = 0;        int flag = 1;        Bank bank = new Bank();        bank.showdata();        while (flag == 1) {            i = -1;            while (i < 0 || i >= M) {                String str = JOptionPane.showInputDialog("请输入需申请资源的进程号（从0到"                        + (M - 1) + "，否则重输入!）");                i = Integer.parseInt(str);                if (i < 0 || i >= M)                    System.out.println("输入的进程号不存在，重新输入!/n");            }            System.out.print("请输入进程" + i + "申请的资源数/n");            for (j = 0; j < N; j++) {                String str = JOptionPane.showInputDialog("资源" + j + ":");                Request[j] = Integer.parseInt(str);                if (Request[j] > NEED[i][j]) {                    System.out.print("进程" + i + "申请的资源数大于进程" + i + "还需要" + j                            + "类资源的资源量!申请不合理，出错!请重新选择!/n");                    flag = 0;                    break;                } else {                    if (Request[j] > AVAILABLE[j]) {                        System.out.print("进程" + i + "申请的资源数大于系统可用" + j                                + "类资源的资源量!申请不合理，出错!请重新选择!/n");                        flag = 0;                        break;                    }                }            }            if (flag == 1) {                bank.changdata(i);                int chkerr = bank.chkerr(i);                if (chkerr == 1) {                    bank.rstordata(i);                    bank.showdata();                } else {                    bank.showdata();                    int check = bank.check0(i);                    if (check == 1) {                        System.out.print("进程" + i + "已经完成，系统将其所占用资源释放/n");                        bank.free(i);                    }                                    }            } else {                bank.showdata();            }            System.out.println("/n");            String str = JOptionPane                    .showInputDialog("是否继续银行家算法演示,按‘1‘键继续,按‘0‘键退出演示");            flag = Integer.parseInt(str);        }    }}