Java实现进程调度算法(一) FCFS(先来先服务)
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FCFS类的calc()即可。
实现思路：按照顺序将进程添加到列表中，然后再按照添加顺序运行。模拟进程的运行，即为按顺序改变每个进程的到达时间、服务时间、开始时间、等待时间、周转时间和带权周转时间。在所有进程都结束后再计算平均周转时间和平均带权周转时间。
三、测试
1. 测试数据：
2. 运行结果：
三、流程图
四、实现代码
1. FCFS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 package xqy.algorithm; 2 3 import java.util.ArrayList; 4 import java.util.Scanner; 5 6 import xqy.Util.Tools; 7 import xqy.been.Process; 8 9 /** 10 * @author xqy 11 * @date 2018年12月19日19:15:01 12 * @description 对先到的任务先处理，后到的任务后处理。 13 */ 14 15 public class FCFS { 16 private int processNumber; 17 private ArrayList<Process> processList; 18 19 public FCFS() { 20 init(); 21 calc(); 22 Tools.printResult(processList); 23 } 24 25 private void init() { 26 Scanner sc = new Scanner(System.in); 27 28 System.out.print("<FCFS> Please enter the process num:"); 29 processNumber = sc.nextInt(); 30 31 processList = new ArrayList<Process>(); 32 for (int i = 0; i < processNumber; i++) { 33 processList.add(new Process()); 34 } 35 36 System.out.println("<FCFS> 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("<FCFS> Please enter each process service time:"); 43 for (int i = 0; i < processNumber; i++) { 44 System.out.print(" Process" + (i + 1) + ":"); 45 processList.get(i).setServicesTime(sc.nextInt()); 46 } 47 } 48 49 private void calc() { 50 int timeNow = 0; 51 Process opProcess; 52 53 for (int i = 0; i < processNumber; i++) { 54 opProcess = processList.get(i); 55 56 int waitTime = timeNow - opProcess.getArrivalTime(); 57 int completionTime = timeNow + opProcess.getServicesTime(); 58 int turnAroundTime = completionTime 59 - opProcess.getArrivalTime(); 60 double turnAroundTimeWithWeight = (double) turnAroundTime 61 / opProcess.getServicesTime(); 62 63 opProcess.setStartTime(timeNow); 64 opProcess.setWaitTime(waitTime); 65 opProcess.setCompletionTime(completionTime); 66 opProcess.setTurnAroundTime(turnAroundTime); 67 opProcess.setTurnAroundTimeWithWeight( 68 turnAroundTimeWithWeight); 69 70 timeNow += opProcess.getServicesTime(); 71 } 72 } 73 74 public static void main(String [] args) { 75 new FCFS(); 76 } 77 }
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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