基于javaweb的操作系统算法

/** * 进程多级反馈队列调度算法 */ package qust.osproject.process.dao; import java.util.LinkedList; import java.util.Queue; import qust.osproject.domain.OSProcess; public class ProcessDaoMFQ extends ProcessDao { // 三个反馈队列 private Queue<OSProcess> q1 = new LinkedList<OSProcess>(); private Queue<OSProcess> q2 = new LinkedList<OSProcess>(); private Queue<OSProcess> q3 = new LinkedList<OSProcess>(); private OSProcess tmProcess = new OSProcess(); private int k = 0; private int t0; private int q = 1; // 时间片长度 /** * 设置时间片长度 * * @param q */ public void setQ(int q) { this.q = q; } /** * 初始化进程列表及进程队列 */ private void init() { q1.clear(); q2.clear(); q3.clear(); for (int i = 0; i < plist.size(); i++) { plist.get(i).setAllocation(0); plist.get(i).setpState(0); plist.get(i).setpPriority(1); } } /** * 设置完成进程的属性：状态、完成时间 * * @param num */ private void setFinish(int num) { for (int i = 0; i < plist.size(); i++) { if (num == plist.get(i).getNum()) { plist.get(i).setFinishTime(t0); plist.get(i).setpState(2); k++; break; } } } /** * 进程多级反馈队列调度算法 */ public void pMFQ() { int s = 0; ProcessSort(); init(); k = 0; t0 = plist.get(0).getArriveTime(); tmProcess = null; while (!(q1.isEmpty() && q2.isEmpty() && q3.isEmpty()) || k < plist.size()) { for (int i = 0; i < plist.size(); i++) { if (plist.get(i).getArriveTime() <= t0 && plist.get(i).getpState() == 0) { q1.add(plist.get(i)); plist.get(i).setpState(1); } } if (tmProcess == null) { if (!q1.isEmpty()) { tmProcess = q1.poll(); s = 0; } else if (!q2.isEmpty()) { tmProcess = q2.poll(); s = 0; } else if (!q3.isEmpty()) { tmProcess = q3.poll(); s = 0; } else { t0++; } } else { if (tmProcess.getpPriority() == 1) { // 正在执行的进程优先级为1 s++; t0++; tmProcess.setAllocation(tmProcess.getAllocation() + 1); if (tmProcess.getAllocation() >= tmProcess.getMaxTime()) { // 进程执行结束 setFinish(tmProcess.getNum()); tmProcess = null; } else if (s >= q) { // 时间片用尽，进入下一优先级队列 tmProcess.setpPriority(tmProcess.getpPriority() + 1); q2.add(tmProcess); tmProcess = null; } } else if (tmProcess.getpPriority() == 2) { // 正在执行的进程优先级为2 if (!q1.isEmpty()) { // 高优先级进程抢占 q1.add(tmProcess); tmProcess = null; } else { s++; t0++; tmProcess.setAllocation(tmProcess.getAllocation() + 1); if (tmProcess.getAllocation() >= tmProcess.getMaxTime()) { // 进程执行结束 setFinish(tmProcess.getNum()); tmProcess = null; } else if (s >= 2 * q) { // 时间片用尽，进入下一优先级队列 tmProcess.setpPriority(tmProcess.getpPriority() + 1); q3.add(tmProcess); tmProcess = null; } } } else if (tmProcess.getpPriority() == 3) { // 正在执行的进程优先级为3 if (!q1.isEmpty() || !q2.isEmpty()) { // 高优先级进程抢占 q3.add(tmProcess); tmProcess = null; } else { s++; t0++; tmProcess.setAllocation(tmProcess.getAllocation() + 1); if (tmProcess.getAllocation() >= tmProcess.getMaxTime()) { // 进程执行结束 setFinish(tmProcess.getNum()); tmProcess = null; } else if (s >= 4 * q) { // 时间片用尽，再次进入队尾 q3.add(tmProcess); tmProcess = null; } } } } } // end of while ProcessSortFinishIN(); } }