用java写个银行家死锁算法
时间: 2023-11-18 18:42:41 浏览: 38
银行家算法是一种避免死锁的算法,核心思想是通过动态地分配系统资源,避免进程因互相占用系统资源而陷入死锁。下面是一个简单的Java实现:
```java
import java.util.Scanner;
public class BankerAlgorithm {
private int[][] need; // 需求矩阵
private int[][] allocation; // 分配矩阵
private int[][] max; // 最大需求矩阵
private int[] available; // 可用资源向量
private int[] request; // 进程请求资源向量
private int[] work; // 工作向量
private boolean[] finish; // 标记数组
private int numberOfProcesses; // 进程数
private int numberOfResources; // 资源数
/**
* 初始化数据
*/
private void init() {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入进程数和资源数(空格分隔):");
numberOfProcesses = scanner.nextInt();
numberOfResources = scanner.nextInt();
need = new int[numberOfProcesses][numberOfResources];
allocation = new int[numberOfProcesses][numberOfResources];
max = new int[numberOfProcesses][numberOfResources];
available = new int[numberOfResources];
request = new int[numberOfResources];
work = new int[numberOfResources];
finish = new boolean[numberOfProcesses];
System.out.println("请输入可用资源数量(空格分隔):");
for (int i = 0; i < numberOfResources; i++) {
available[i] = scanner.nextInt();
work[i] = available[i];
}
System.out.println("请输入每个进程的最大需求量(空格分隔):");
for (int i = 0; i < numberOfProcesses; i++) {
for (int j = 0; j < numberOfResources; j++) {
max[i][j] = scanner.nextInt();
}
}
System.out.println("请输入每个进程已分配的资源量(空格分隔):");
for (int i = 0; i < numberOfProcesses; i++) {
for (int j = 0; j < numberOfResources; j++) {
allocation[i][j] = scanner.nextInt();
need[i][j] = max[i][j] - allocation[i][j];
}
}
}
/**
* 判断是否能够分配资源
*
* @param process 进程编号
* @return 是否能够分配
*/
private boolean canAllocate(int process) {
for (int i = 0; i < numberOfResources; i++) {
if (request[i] > need[process][i] || request[i] > work[i]) {
return false;
}
}
return true;
}
/**
* 分配资源
*
* @param process 进程编号
*/
private void allocate(int process) {
for (int i = 0; i < numberOfResources; i++) {
work[i] -= request[i];
allocation[process][i] += request[i];
need[process][i] -= request[i];
}
finish[process] = true;
}
/**
* 释放资源
*
* @param process 进程编号
*/
private void release(int process) {
for (int i = 0; i < numberOfResources; i++) {
work[i] += allocation[process][i];
allocation[process][i] = 0;
need[process][i] = 0;
}
finish[process] = false;
}
/**
* 执行银行家算法
*/
public void execute() {
init();
while (true) {
boolean canFinish = false;
for (int i = 0; i < numberOfProcesses; i++) {
if (!finish[i] && canAllocate(i)) {
allocate(i);
canFinish = true;
System.out.println("分配资源给进程" + i);
break;
}
}
if (!canFinish) {
System.out.println("无法分配资源,系统处于不安全状态");
return;
}
boolean allFinish = true;
for (int i = 0; i < numberOfProcesses; i++) {
if (!finish[i]) {
allFinish = false;
break;
}
}
if (allFinish) {
System.out.println("所有进程都能够完成,系统处于安全状态");
return;
}
}
}
public static void main(String[] args) {
BankerAlgorithm bankerAlgorithm = new BankerAlgorithm();
bankerAlgorithm.execute();
}
}
```
以上代码只是一个简单的实现,具体实现可能会因为不同的场景而有所不同。