用java语言模拟实现操作系统的进程调度算法,先来先服务,高优先级、时间片轮转
时间: 2023-06-16 19:04:34 浏览: 339
计算机系统课程设计-本科毕业
好的,我可以为您提供一个基本的Java代码示例来模拟实现操作系统的进程调度算法,包括先来先服务、高优先级和时间片轮转。
首先,我们需要定义一个进程类Process,其中包含进程的ID、优先级、到达时间、服务时间、剩余服务时间和完成时间等属性。代码如下:
```java
class Process {
int id; // 进程ID
int priority; // 进程优先级
int arriveTime; // 到达时间
int serviceTime; // 服务时间
int remainingTime; // 剩余服务时间
int finishTime; // 完成时间
public Process(int id, int priority, int arriveTime, int serviceTime) {
this.id = id;
this.priority = priority;
this.arriveTime = arriveTime;
this.serviceTime = serviceTime;
this.remainingTime = serviceTime;
this.finishTime = -1;
}
}
```
接下来,我们定义一个进程调度类Scheduler,其中包含了三种不同的进程调度算法:先来先服务、高优先级和时间片轮转。代码如下:
```java
import java.util.ArrayList;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.Queue;
class Scheduler {
ArrayList<Process> processes; // 进程列表
public Scheduler(ArrayList<Process> processes) {
this.processes = processes;
}
// 先来先服务
public void FCFS() {
int currentTime = 0;
int n = processes.size();
for (int i = 0; i < n; i++) {
Process p = processes.get(i);
if (p.arriveTime > currentTime) {
currentTime = p.arriveTime;
}
p.finishTime = currentTime + p.serviceTime;
currentTime = p.finishTime;
}
}
// 高优先级
public void HPF() {
int currentTime = 0;
int n = processes.size();
ArrayList<Process> queue = new ArrayList<Process>();
for (int i = 0; i < n; i++) {
Process p = processes.get(i);
if (p.arriveTime <= currentTime) {
queue.add(p);
}
}
queue.sort(new Comparator<Process>() {
@Override
public int compare(Process p1, Process p2) {
return p2.priority - p1.priority;
}
});
while (!queue.isEmpty()) {
Process p = queue.remove(0);
p.finishTime = currentTime + p.serviceTime;
currentTime = p.finishTime;
for (int i = 0; i < n; i++) {
Process q = processes.get(i);
if (q.arriveTime > currentTime) {
break;
}
if (!queue.contains(q) && q != p) {
queue.add(q);
}
}
queue.sort(new Comparator<Process>() {
@Override
public int compare(Process p1, Process p2) {
return p2.priority - p1.priority;
}
});
}
}
// 时间片轮转
public void RR(int quantum) {
int currentTime = 0;
int n = processes.size();
Queue<Process> queue = new LinkedList<Process>();
for (int i = 0; i < n; i++) {
Process p = processes.get(i);
if (p.arriveTime <= currentTime) {
queue.add(p);
}
}
while (!queue.isEmpty()) {
Process p = queue.remove();
if (p.remainingTime > quantum) {
p.remainingTime -= quantum;
currentTime += quantum;
for (int i = 0; i < n; i++) {
Process q = processes.get(i);
if (q.arriveTime <= currentTime && !queue.contains(q) && q != p) {
queue.add(q);
}
}
queue.add(p);
} else {
currentTime += p.remainingTime;
p.remainingTime = 0;
p.finishTime = currentTime;
for (int i = 0; i < n; i++) {
Process q = processes.get(i);
if (q.arriveTime <= currentTime && !queue.contains(q) && q != p) {
queue.add(q);
}
}
}
}
}
}
```
在主函数中,我们可以创建一些进程并利用上述三种算法进行调度。代码如下:
```java
public class Main {
public static void main(String[] args) {
ArrayList<Process> processes = new ArrayList<Process>();
processes.add(new Process(1, 2, 0, 10));
processes.add(new Process(2, 1, 0, 5));
processes.add(new Process(3, 3, 2, 7));
processes.add(new Process(4, 4, 3, 2));
Scheduler scheduler = new Scheduler(processes);
scheduler.FCFS();
//scheduler.HPF();
//scheduler.RR(2);
for (int i = 0; i < processes.size(); i++) {
Process p = processes.get(i);
System.out.println("Process " + p.id + ": finish time = " + p.finishTime);
}
}
}
```
注释:在主函数中,我们创建了四个进程,并调用Scheduler类的FCFS()、HPF()和RR(2)方法进行调度。在调度结束后,我们可以输出每个进程的完成时间。请注意,由于我们在进程类中定义了finishTime属性,因此调度算法可以直接修改该属性以记录每个进程的完成时间。
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