Java实现进程调度算法(二) RR(时间片轮转)
2024-10-19 02:20:55
一、概述
因为这次os作业对用户在控制台的输入输出有要求，所以我花了挺多的代码来完善控制台的显示。
也因为我这次要实现多个类似算法，所以将一些共性单独提取出来作为一个类。
如果只想要和算法有关的核心代码，看RR类的calc()即可。
实现思路：每运行一个进程，则将所有进程的remainServiceTime减去一个时间片的长度。
二、运行结果
1. 测试数据：
2. 运行结果：
三、流程图
四、实现代码
1. RR类（主类）
只有calc()中涉及了算法，init()和printResult()只有简单的输入输出操作。
package xqy.algorithm; import java.util.*; import xqy.Util.Tools;
import xqy.been.Process; /**
* @author xqy
* @date 2018年12月19日19:14:49
*/
public class RR {
private int processNumber;
private ArrayList<Process> processList;
private int timeSlice; public RR() {
init();
calc();
Tools.printResult(processList);
} private void init() {
Scanner sc = new Scanner(System.in); System.out.print("<RR> Please enter the slice time:");
timeSlice = sc.nextInt();
System.out.print("<RR> please enter the process num:");
processNumber = sc.nextInt(); processList = new ArrayList<Process>();
for (int i = 0; i < processNumber; i++) {
processList.add(new Process());
} System.out.println("<RR> Please enter each process arrival time:");
for (int i = 0; i < processNumber; i++) {
System.out.print(" Process" + (i + 1) + ":");
processList.get(i).setArrivalTime(sc.nextInt());
} System.out.println("<RR> Please enter each process service time:");
for (int i = 0; i < processNumber; i++) {
System.out.print(" Process" + (i + 1) + ":");
int servicesTime = sc.nextInt(); processList.get(i).setServicesTime(servicesTime);
processList.get(i).setRemainServiceTime(servicesTime);
}
} private void calc() {
int timeNow = 0;
int processRemain = processNumber;
boolean noProcessRunInThisTurn;
Process opProcess; while (processRemain != 0) {
noProcessRunInThisTurn = true; for (int i = 0; i < processNumber; i++) {
opProcess = processList.get(i); if ((opProcess.getRemainServiceTime() > 0)
&& (timeNow >= opProcess.getArrivalTime())) {
// First time
if (opProcess.getServicesTime() == opProcess
.getRemainServiceTime()) {
int waitTime = timeNow - opProcess.getArrivalTime(); opProcess.setStartTime(timeNow);
opProcess.setWaitTime(waitTime);
} // Calculating remain service time
int remainServiceTime = opProcess.getRemainServiceTime()
- timeSlice;
opProcess.setRemainServiceTime(remainServiceTime); // Last time
if (remainServiceTime <= 0) {
int completionTime = timeNow + timeSlice; // The process ends when the current slice is completed.
int turnAroundTime = completionTime
- opProcess.getArrivalTime();
double turnAroundTimeWithWeight = 1.0 * turnAroundTime
/ opProcess.getServicesTime(); opProcess.setCompletionTime(completionTime);
opProcess.setTurnAroundTime(turnAroundTime);
opProcess
.setTurnAroundTimeWithWeight(turnAroundTimeWithWeight);
processRemain--;
} timeNow += timeSlice;
noProcessRunInThisTurn = false; System.out.println(" #STEP# Process" + (i + 1)
+ " remain service time:"
+ opProcess.getRemainServiceTime()
+ " , timeBefore:" + (timeNow - 1) + ", timeNow:"
+ timeNow
+ ((remainServiceTime <= 0) ? " Finish" : ""));
} else {
// do noting, because this process has been completed or hasn`t arrived.
}
} // Means no process could run, because they have arrived.
if ((processRemain > 0) && noProcessRunInThisTurn) {
timeNow += timeSlice;
}
}
}
}
2. Process类
模拟了进程，对属性进行了封装。
1 package xqy.been;
2
3 public class Process {
4 private int arrivalTime;
5 private int servicesTime;
6 private int remainServiceTime;
7 private int startTime;
8 private int waitTime;
9 private int completionTime;
10
11 /**
12 * turnAroundTime = completionTime - arrivalTime
13 */
14 private int turnAroundTime;
15
16 /**
17 * turnAroundTimeWithWeight = turnAroundTime / servicesTime
18 */
19 private double turnAroundTimeWithWeight;
20
21 public Process() {
22 ;
23 }
24
25 public int getArrivalTime() {
26 return arrivalTime;
27 }
28
29 public void setArrivalTime(int arrivalTime) {
30 this.arrivalTime = arrivalTime;
31 }
32
33 public int getServicesTime() {
34 return servicesTime;
35 }
36
37 public void setServicesTime(int servicesTime) {
38 this.servicesTime = servicesTime;
39 }
40
41 public int getRemainServiceTime() {
42 return remainServiceTime;
43 }
44
45 public void setRemainServiceTime(int remainServiceTime) {
46 this.remainServiceTime = remainServiceTime;
47 }
48
49 public int getStartTime() {
50 return startTime;
51 }
52
53 public void setStartTime(int startTime) {
54 this.startTime = startTime;
55 }
56
57 public int getWaitTime() {
58 return waitTime;
59 }
60
61 public void setWaitTime(int waitTime) {
62 this.waitTime = waitTime;
63 }
64
65 public int getCompletionTime() {
66 return completionTime;
67 }
68
69 public void setCompletionTime(int completionTime) {
70 this.completionTime = completionTime;
71 }
72
73 public int getTurnAroundTime() {
74 return turnAroundTime;
75 }
76
77 public void setTurnAroundTime(int turnAroundTime) {
78 this.turnAroundTime = turnAroundTime;
79 }
80
81 public double getTurnAroundTimeWithWeight() {
82 return turnAroundTimeWithWeight;
83 }
84
85 public void setTurnAroundTimeWithWeight(double turnAroundTimeWithWeight) {
86 this.turnAroundTimeWithWeight = turnAroundTimeWithWeight;
87 }
88
89 @Override
90 public String toString() {
91 return "Process [arrivalTime=" + arrivalTime + ", servicesTime="
92 + servicesTime + ", remainServiceTime=" + remainServiceTime
93 + ", startTime=" + startTime + ", waitTime=" + waitTime
94 + ", completionTime=" + completionTime + ", turnAroundTime="
95 + turnAroundTime + ", turnAroundTimeWithWeight="
96 + turnAroundTimeWithWeight + "]";
97 }
98 }
3. Tools类
因为这次要实现几个类似的算法，所以我把每个算法中都要用到的方法都提取出来作为单独的工具类。
也可以将这些工具方法都放入FCFS类中。
1 package xqy.Util;
2
3 import java.util.ArrayList;
4
5 import xqy.been.Process;
6
7 public class Tools {
8
9 public static double calcAverageTurnAroundTime(
10 ArrayList<Process> processList) {
11 double sum = 0;
12 for (int i = 0; i < processList.size(); i++) {
13 sum += processList.get(i).getTurnAroundTime();
14 }
15 return Math.round(sum / processList.size() * 100) / 100.0;
16 }
17
18 public static double calcAverageTurnAroundTimeWithWeight(
19 ArrayList<Process> processList) {
20 double sum = 0;
21 for (int i = 0; i < processList.size(); i++) {
22 sum += processList.get(i).getTurnAroundTimeWithWeight();
23 }
24 return Math.round(sum / processList.size() * 100) / 100.0;
25 }
26
27 public static void printResult(ArrayList<Process> processList) {
28 System.out.println("\n #RESULT#");
29
30 System.out.print("\tArrive:\t\t");
31 for (int i = 0; i < processList.size(); i++) {
32 System.out.print(processList.get(i).getArrivalTime() + "\t");
33 }
34 System.out.println();
35
36 System.out.print("\tService:\t");
37 for (int i = 0; i < processList.size(); i++) {
38 System.out.print(processList.get(i).getServicesTime() + "\t");
39 }
40 System.out.println();
41
42 System.out.print("\tStart:\t\t");
43 for (int i = 0; i < processList.size(); i++) {
44 System.out.print(processList.get(i).getStartTime() + "\t");
45 }
46 System.out.println();
47
48 System.out.print("\tWait:\t\t");
49 for (int i = 0; i < processList.size(); i++) {
50 System.out.print(processList.get(i).getWaitTime() + "\t");
51 }
52 System.out.println();
53
54 System.out.print("\tFinish:\t\t");
55 for (int i = 0; i < processList.size(); i++) {
56 System.out.print(processList.get(i).getCompletionTime() + "\t");
57 }
58 System.out.println();
59
60 System.out.print("\tTurn around:\t");
61 for (int i = 0; i < processList.size(); i++) {
62 System.out.print(processList.get(i).getTurnAroundTime() + "\t");
63 }
64 System.out.println();
65
66 System.out.print("\tTA wight:\t");
67 for (int i = 0; i < processList.size(); i++) {
68 System.out.print(Math.round(processList.get(i)
69 .getTurnAroundTimeWithWeight() * 100) / 100.0 + "\t");
70 }
71 System.out.println();
72
73 System.out.println("\tAverage turn around time:"
74 + Tools.calcAverageTurnAroundTime(processList) + "\t");
75 System.out.println("\tAverage turn around time with wight:"
76 + Tools.calcAverageTurnAroundTimeWithWeight(processList));
77
78 System.out.println();
79 }
80 }
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