sjfprocessschedule.java~4~

来自「进程调度和存储管理模拟」· JAVA~4~ 代码 · 共 63 行

package cn.edu.cauc.crab.ossimulate;

/**
 * <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 short process first process scheduling.
 *
 * @author Crab
 * @version 0.1
 * @see cn.edu.cauc.crab.ossimulate.ProcessSchdule
 */
public class SPFProcessSchedule extends ProcessSchedule {

    /**
     * extends from ProcessSchedule a List named PCBs
     */
    public SPFProcessSchedule() {
        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 pcb = (PCB)PCBs.get(0);//get the fist come process
            PCBs.remove(0);// remove it from PCBs after finish.

            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;
                float ts = pcb.serveTime;
                pcb.nullWorkRate =  tr / ts;

                System.out.println("Arrive: " + pcb.arriveTime
                                   + " Serve: " + pcb.serveTime
                                   + " Begin: " + pcb.beginTime
                                   + " Finish: " + pcb.finishTime
                                   + " Roll: " + pcb.rollTime
                                   + " nullWorkRate: " + pcb.nullWorkRate);
            }
        }
    }

    public static void main(String[] args) {
        SPFProcessSchedule SPFProcessSchedule1 = new SPFProcessSchedule();
    }
}