fpfprocessschedule.java~25~

来自「进程调度和存储管理模拟」· JAVA~25~ 代码 · 共 96 行

package cn.edu.cauc.crab.ossimulate;

import java.util.*;

/**
 * <p>Title: OS simulate</p>
 * <p>Description: This is my home work.</p>
 * <p>Copyright: Copyleft (c) 2004</p>
 * <p>Company: CAUC</p>
 * @author Crab
 * @version 0.1
 */

/**
 * To simulate the high responsibility first process scheduling.
 *
 * @author Crab
 * @version 0.1
 * @see cn.edu.cauc.crab.ossimulate.ProcessSchdule
 */
public class FPFProcessSchedule extends ProcessSchedule {

    /**
     * extends from ProcessSchedule a List named PCBs
     */
    public FPFProcessSchedule() {
        super();
    }

    /**
     * extends from ProcessSchedule
     * After addProcess() is calling,
     * use to start scheduling.
     */
    public void start() {
        int time = 0;//set the beging time

        while (!PCBs.isEmpty()) {
            PCB hightest = (PCB)PCBs.get(0);
            float tw = hightest.waitTime;
            float ts = hightest.serveTime;
            hightest.responsibility = (tw + ts) / ts;

            Iterator p = PCBs.iterator();
            while (p.hasNext()) {
                PCB tempPCB = (PCB)p.next();
                if (time >= tempPCB.arriveTime) {
                    tempPCB.waitTime = time - tempPCB.arriveTime;
                    tw = tempPCB.waitTime;
                    ts = tempPCB.serveTime;
                    tempPCB.responsibility = (tw + ts) / ts;
                    if (tempPCB.responsibility > hightest.responsibility) {
                        hightest = tempPCB;
                    }
                }
            }

            PCB pcb = hightest;

            if (time >= pcb.arriveTime) {// the process must run >= arrive time
                pcb.beginTime = time;
                time += pcb.serveTime;
                pcb.finishTime = time;
                pcb.rollTime = pcb.finishTime - pcb.arriveTime;
                // use tr ts to rise the precesion.
                float tr = pcb.rollTime;
                ts = pcb.serveTime;
                pcb.nullWorkRate =  tr / ts;

                System.out.println("PID: " + pcb.pid
                                   +" Responsibility:" + pcb.responsibility
                                   + "Arrive: " + pcb.arriveTime
                                   + " Serve: " + pcb.serveTime
                                   + " Begin: " + pcb.beginTime
                                   + " Finish: " + pcb.finishTime
                                   + " Roll: " + pcb.rollTime
                                   + " nullWorkRate: " + pcb.nullWorkRate);
                PCBs.remove(pcb);
            } else {
                time++;
            }
        }
    }

    //for unit test
    public static void main(String[] args) {
        ProcessSchedule pSch = new FPFProcessSchedule();

        //pSch.addProcess(new Process(4), 0);
        pSch.addProcess(new Process(3), 1);
        pSch.addProcess(new Process(5), 2);
        pSch.addProcess(new Process(2), 3);
        pSch.addProcess(new Process(4), 4);
        pSch.start();
    }
}