OS

public class TestTheBanker {

public static void main(String[] args) { Scanner scanner = new Scanner(System.in); TheBanker tb = new TheBanker(); tb.deadlockAvoidance();//死锁避免 int gate = 1; while(gate!=0){

tb.deadlockDetection();//死锁检测

System.out.println(\"如果您要继续分配资源请输入\\\"1\\\"，退出请输入\\\"0\\\"\");

System.out.print(\"您输入的值为：\"); gate = scanner.nextInt(); System.out.println(); }

System.out.println(\"使用愉快！期待您下次使用！\"); } }

class TheBanker{ int m; int n;

int[][] max;

int[][] maxbak;//备份用 int[][] allocation;

int[][] allocationbak;//备份用 int[][] need;

int[][] needbak;//备份用 int[] available;

int[] availablebak;//备份用

public TheBanker(){

Scanner s = new Scanner(System.in);

System.out.println(\"初始化==============\");

System.out.print(\"请依次输入系统中的【进程数】和【资源类型数】：\"); m = s.nextInt(); n = s.nextInt();

max =new int[m][n]; maxbak = new int[m][n];

allocation = new int[m][n]; allocationbak = new int[m][n]; need = new int[m][n]; needbak = new int[m][n];

available = new int[n]; availablebak = new int[n];

for(int i=0;iSystem.out.print(\"请依次输入第\" + i + \"进程的各资源数：\"); for(int j=0;j}

for(int i=0;iallocationbak[i][j] = allocation[i][j]; } }

for(int i=0;ineed[i][j] = max[i][j] - allocation[i][j]; needbak[i][j] = need[i][j]; }

}

for(int i=0;iSystem.out.print(\"请输入系统中第\" + i + \"种资源的剩余量：\"); available[i] = s.nextInt(); availablebak[i] = available[i]; }

System.out.println(\"初始化结果=============\");

System.out.println(\" MAX ALLOCATION NEED AVAILABLE\"); for(int i=0;iSystem.out.print(\"P\" + i + \": \"); for(int j=0;jif(max[i][j]>9){//如果是两位数，控制格式，在数字前少输出一个\" \"。

System.out.print(max[i][j] + \" \"); }else{

System.out.print(\" \" + max[i][j] + \" \"); } }

System.out.print(\" \"); for(int j=0;jif(allocation[i][j]>9){

System.out.print(allocation[i][j] + \" \"); }else{

System.out.print(\" \" + allocation[i][j] + \" \"); } }

System.out.print(\" \"); for(int j=0;j9){

System.out.print(need[i][j] + \" \"); }else{

System.out.print(\" \" + need[i][j] + \" \"); } }

if(i==0){

System.out.print(\" \"); for(int j=0;j9){

System.out.print(available[j] + \" \"); }else{

System.out.print(\" \" + available[j] + \" \"); } } }

System.out.println(); }

System.out.println(\"=====完成初始化=====\"); System.out.println(); }

public void deadlockAvoidance(){ int[] security = new int[m];

boolean[] param = new boolean[m]; int[] tar = new int[n]; int count = 0;

int num1 = m+1;//计数器,每循环一遍所有进程就自减1 int num2 = m;//计数器，每遇到一个被满足的进程就自减1

while(num1>0){//如果num1==0，则说明依次循环下来没有能够满足的进程，因此中止

for(int i=0;iif(param[i]==false){//只有没有被满足的进程才可以进入内层循环 param[i] = true;

for(int j=0;jtar[j] = available[j] - need[i][j]; if(tar[j]<0){

param[i] = false; } }

if(param[i]==true){

for(int k=0;kavailable[k] = available[k] + allocation[i][k]; }

security[count] = i;//记录以满足的进程号 count++; num2--; }

} }

num1--;

while((num2==0)&&(num1>0)){

System.out.print(\"【安全序列】为：\"); for(int i=0;iSystem.out.print(\"P\" + security[i]); }else{

System.out.print(\"P\" + security[i] + \"-->\"); } }

System.out.println();

System.out.println(\"=====【死锁避免】结束=====\"); System.out.println(); return; }

while((num1==0)&&(num2>0)){

System.out.println(\"抱歉！没有【安全序列】！\"); System.out.println(\"=====【死锁避免】结束=====\"); System.out.println(); return; }

} }

public void deadlockDetection(){

Scanner sc = new Scanner(System.in); int key;

int[] security = new int[m];

boolean[] param = new boolean[m];

int[] temp = new int[n]; int[] tar = new int[n]; int count = 0;

int num1 = m+1;//计数器,每循环一遍所有进程就自减1 int num2 = m;//计数器，每遇到一个被满足的进程就自减1

for(int i=0;iallocation[i][j] = allocationbak[i][j]; need[i][j] = needbak[i][j]; available[j] = availablebak[j]; } }

System.out.println();

System.out.println(\"死锁检测============\");

System.out.println(\"如果您此时想申请系统资源请输入【进程号】和\"+n+\"种【资源量】，系统将帮您判断是否可行。\"); System.out.print(\"您输入的进程号为：\"); key = sc.nextInt(); for(int i=0;iSystem.out.print(\"您要申请的第\"+i+\"种资源的数量为：\"); temp[i] = sc.nextInt(); }

for(int i=0;iallocation[key][i] = allocation[key][i] + temp[i]; need[key][i] = need[key][i] - temp[i]; if(need[key][i]<0){

System.out.println(\"申请资源大于所需资源，系统【不能】分配资源！\");

for(int k=0;kavailable[j] = availablebak[j]; }

max[k][j] = maxbak[k][j];

allocation[k][j] = allocationbak[k][j]; need[k][j] = needbak[k][j]; } }

return; }

available[i] = available[i] - temp[i]; if(available[i]<0){

System.out.println(\"申请资源大于系统所剩资源，系统【不能】分配资源！\");

for(int k=0;kavailable[j] = availablebak[j]; }

max[k][j] = maxbak[k][j];

allocation[k][j] = allocationbak[k][j]; need[k][j] = needbak[k][j]; } }

return; } }

System.out.println(\"申请资源时各进程的状态=============\");

System.out.println(\" MAX ALLOCATION NEED AVAILABLE\"); for(int i=0;iSystem.out.print(\"P\" + i + \": \"); for(int j=0;j9){

System.out.print(max[i][j] + \" \"); }else{

System.out.print(\" \" + max[i][j] + \" \"); } }

System.out.print(\" \"); for(int j=0;jif(allocation[i][j]>9){

System.out.print(allocation[i][j] + \" \"); }else{

System.out.print(\" \" + allocation[i][j] + \" \"); } }

System.out.print(\" \"); for(int j=0;j9){

System.out.print(need[i][j] + \" \"); }else{

System.out.print(\" \" + need[i][j] + \" \"); } }

if(i==0){

System.out.print(\" \"); for(int j=0;j9){

System.out.print(available[j] + \" \"); }else{

System.out.print(\" \" + available[j] + \" \"); } } }

System.out.println(); }

System.out.println(\"=====完成状态展示=====\"); System.out.println();

while(num1>0){//如果num1==0，则说明依次循环下来没有能够满足的进程，因此中止

for(int i=0;iif(param[i]==false){//只有没有被满足的进程才可以进入内层循环 param[i] = true;

for(int j=0;jtar[j] = available[j] - need[i][j]; if(tar[j]<0){

param[i] = false; } }

if(param[i]==true){

for(int k=0;kavailable[k] = available[k] + allocation[i][k]; }

security[count] = i;//记录以满足的进程号 count++; num2--; }

} }

num1--;

while((num2==0)&&(num1>0)){

System.out.print(\"【安全序列】为：\"); for(int i=0;iSystem.out.print(\"P\" + security[i]); }else{

System.out.print(\"P\" + security[i] + \"-->\"); } }

System.out.println();

System.out.println(\"可以产生新的安全序列！系统【能】将申请的资源分配给P\"+ key +\"！\");

System.out.println(\"=====死锁检测结束=====\"); System.out.println(); return; }

while((num1==0)&&(num2>0)){

System.out.println(\"抱歉！【没有】安全序列！\");

System.out.println(\"系统【不能】将申请的资源分配给P\"+ key +\"！\"); System.out.println(\"=====死锁检测结束=====\"); System.out.println(); return; } } } }