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。

1 packagexqy.algorithm;2

3 import java.util.*;4

5 importxqy.Util.Tools;6 importxqy.been.Process;7

8 /**

9 *@authorxqy10 * @date 2018年12月19日19:14:4911 */

12 public classRR {13 private intprocessNumber;14 private ArrayListprocessList;15 private inttimeSlice;16

17 publicRR() {18 init();19 calc();20 Tools.printResult(processList);21 }22

23 private voidinit() {24 Scanner sc = newScanner(System.in);25

26 System.out.print(" Please enter the slice time:");27 timeSlice =sc.nextInt();28 System.out.print(" please enter the process num:");29 processNumber =sc.nextInt();30

31 processList = new ArrayList();32 for (int i = 0; i < processNumber; i++) {33 processList.add(newProcess());34 }35

36 System.out.println(" Please enter each process arrival time:");37 for (int i = 0; i < processNumber; i++) {38 System.out.print(" Process" + (i + 1) + ":");39 processList.get(i).setArrivalTime(sc.nextInt());40 }41

42 System.out.println(" Please enter each process service time:");43 for (int i = 0; i < processNumber; i++) {44 System.out.print(" Process" + (i + 1) + ":");45 int servicesTime =sc.nextInt();46

47 processList.get(i).setServicesTime(servicesTime);48 processList.get(i).setRemainServiceTime(servicesTime);49 }50 }51

52 private voidcalc() {53 int timeNow = 0;54 int processRemain =processNumber;55 booleannoProcessRunInThisTurn;56 Process opProcess;57

58 while (processRemain != 0) {59 noProcessRunInThisTurn = true;60

61 for (int i = 0; i < processNumber; i++) {62 opProcess =processList.get(i);63

64 if ((opProcess.getRemainServiceTime() > 0)65 && (timeNow >=opProcess.getArrivalTime())) {66 //First time

67 if (opProcess.getServicesTime() ==opProcess68 .getRemainServiceTime()) {69 int waitTime = timeNow -opProcess.getArrivalTime();70

71 opProcess.setStartTime(timeNow);72 opProcess.setWaitTime(waitTime);73 }74

75 //Calculating remain service time

76 int remainServiceTime =opProcess.getRemainServiceTime()77 -timeSlice;78 opProcess.setRemainServiceTime(remainServiceTime);79

80 //Last time

81 if (remainServiceTime <= 0) {82 int completionTime = timeNow + timeSlice; //The process ends when the current slice is completed.

83 int turnAroundTime =completionTime84 -opProcess.getArrivalTime();85 double turnAroundTimeWithWeight = 1.0 *turnAroundTime86 /opProcess.getServicesTime();87

88 opProcess.setCompletionTime(completionTime);89 opProcess.setTurnAroundTime(turnAroundTime);90 opProcess91 .setTurnAroundTimeWithWeight(turnAroundTimeWithWeight);92 processRemain--;93 }94

95 timeNow +=timeSlice;96 noProcessRunInThisTurn = false;97

98 System.out.println(" #STEP# Process" + (i + 1)99 + " remain service time:"

100 +opProcess.getRemainServiceTime()101 + " , timeBefore:" + (timeNow - 1) + ", timeNow:"

102 +timeNow103 + ((remainServiceTime <= 0) ? " Finish" : ""));104 } else{105 //do noting, because this process has been completed or hasn`t arrived.

106 }107 }108

109 //Means no process could run, because they have arrived.

110 if ((processRemain > 0) &&noProcessRunInThisTurn) {111 timeNow +=timeSlice;112 }113 }114 }115 }

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 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 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 processList) {

28 System.out.println("n #RESULT#");

29

30 System.out.print("tArrive:tt");

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:tt");

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:tt");

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:tt");

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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