java实现银行家算法

java实现银行家算法

本文实例为大家分享了java实现银行家算法的具体代码，供大家参考，具体内容如下

import java.util.Arrays;

import javax.swing.JOptionPane;

public class BalubRumyofnker_Dijkstra {

static int available[]={3,3,2}; //可利用资源数

static int max[][]={{7,5,3},{3,2,2},{9,0,2},{2,2,2},{4,3,3}};; //每线程最大需求

static int allocation[][]={{0,1,0},{2,0,0},{3,0,2},{2,1,1},{0,0,2}}; //已分配资源

static int need[][]={{7,4,3},{1,2,2},{6,0,0},{0,1,1},{4,3,1}}; //需求

static int request[]=new int[3]; //存放请求资源

static int thread; //线程号

static JOptionPane jpane = new JOptionPane();

// static boolean m;

public static void main(String[] argv){

int n = 0 ;

Banker_Dijkstra bd = new Banker_Dijkstra();

for(int i=0;i<5;i++){

if(bd.safeState(i)){

JOptionPane.showMessageDialog(jpane, "系统状态安全");

n=1;

break;

}else{

n=2;

continue;

}

}

if(n==1){

bd.getThread();

}

else if(n==2){

JOptionPane.showMessageDialog(jpane, "系统状态不安全");

}

}

protected void getThread(){//输入测试线程号且输出结果

try{

String xiancheng = JOptionPane.showInputDialog(jpane,"请输入申请资源的线程:");

thread = (int) Integer.parseInt(xiancheng);

}catch(Exception e){

int response = JOptionPane.showConfirmDialog(jpane, "请输入0～4:",null, JOptionPane.YES_NO_OPTION);

// 处理异常

if(response==0){

getThread();

}else if(response ==1){

System.exit(0);

}

}

if(thread<0||thread>4){

JOptionPane.showMessageDialog(jpane, "请输入0～4:");

getThread();

}else{

for(int i=0;i<3;i++){

String requestR = JOptionPane.showInputDialog(jpane,"请输入申请的第"+(i+1)+"种资源(若不申请则填0)");

try{

request[i]=Integer.parseInt(requestR);}

catch(Exception e){

JOptionPane.showConfirmDialog(jpane, "请输入申请的第"+(i+1)+"种资源(若不申请则填0)",null,JOptionPane.YES_NO_OPTION);

}

}

if(request[0]>need[thread][0]||request[1]>need[thread][1]||request[2]>need[thread][2]){

JOptionPane.showMessageDialog(jpane,thread+"线程申请的资源超出其需要的资源，请重新输入");

getThread();

}else{

if(request[0]> available[0]||request[1]> available[1]||request[2]> available[2]){

JOptionPane.showMessageDialog(jpane,thread+"线程申请的资源大于系统资源，请重新输入");

getThread();

}

}

// 分配资源

allocateData(thread);

// 判断 继续模拟选择与处理

int tag=0;

if(check(thread)){

try{

String str = JOptionPane.showInputDialog(jpane,"是／否 继续模拟？( 1/0 ):");

tag = Integer.parseInt(str);

}catch(Exception e){

JOptionPane.showMessageDialog(jpane, "继续 输入(数值) 1，不继续 输入(数值) 0 ！");

}

if(tag==1){

recoverData(thread);

getThread();

}

else{

if( (JOptionPane.YES_NO_OPTION)==JOptionPane.CANCEL_OPTION)System.exit(0);

if((JOptionPane.YES_NO_OPTION)==JOptionPane.YES_OPTION) recoverData(thread);

}

}else{

recoverData(thread);

getThread();

}

}

}

// 安全算法

private boolean check(int thread2) {

boolean[] finish = new boolean[5];

Arrays.fill(finish, false);

int[] work = new int[3];

int[] queue = new int[5];

int q=0;//安全序列下标

for(int i = 0;i<3;i++){

work[i] = available[i];

}

int tT = thread2;

while(tT<5){

for(int R=0;R<3;R++){

if((!(finish[tT]==false))||(!(work[R]>=need[tT][R]))){

tT++;

break;

}else{

if(R==2){

for(int m =0;m<3;m++){

work[m] += allocation[tT][m];

}

for(int s:work){

System.out.print(s+" ");

}

System.out.println("");

finish[tT] = true;

queue[q] = tT;

q++;

tT =0;

}

}

}

}

for(int p =0;p<5;p++){

if(finish[p]==false){

JOptionPane.showMessageDialog(jpane, "安全序列生成失败");

return false;

}

}

JOptionPane.showMessageDialog(jpane, "安全序列："+queue[0]+","+queue[1]+","

+queue[2]+","+queue[3]+","+queue[4]);

return true;

}

private boolean safeState(int thread3){

boolean[] finish = new boolean[5];

Arrays.fill(finish, false);

int[] work = new int[3];

int[] queue = new int[5];

int q=0;//安全序列下标

for(int i = 0;i<3;i++){

work[i] = available[i];

}

int tT = thread3;

while(tT<5){

for(int R=0;R<3;R++){

if((!(finish[tT]==false))||(!(work[R]>=need[tT][R]))){

tT++;

break;

}

else{

if(R==2){

for(int m =0;m<3;m++){

work[m] += allocation[tT][m];

}

finish[tT] = true;

queue[q] = tT;

q++;

tT =0;

}

}

// if((finish[tT]==false)&&(work[R]>=need[tT][R])){

// for(int m =0;m<3;m++){

// work[m] += allocation[tT][m];}

// finish[tT] = true;

// queue[q] = tT;

// q++;

// tT=0;

// }else{

// tT++;

// break;

// }

}

}

for(int p =0;p<5;p++){

if(finish[p]==false){

return false;

}

}

return true;

}

private void recoverData(int thread2) { // 生成失败则重置已分配资源

for(int i=0;i<3;i++){

//重新调整系统资源数

available[i]+=request[i];

//计算各个线程拥有资源

allocation[thread2][i]-=request[i];

//重新计算需求

need[thread2][i]+=request[i];

}

}

private void allocateData(int thread2) { //分配

for(int i=0;i<3;i++){

//重新调整可用系统资源数

available[i]-=request[i];

//计算各个线程分配后拥有资源

allocation[thread2][i]+=request[i];

//重新计算需求

need[thread2][i]-=request[i];

}

}

}

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。