ScheduleIterator接口
import java.util.Date;
public
interface ScheduleIterator
{
public Date next();//获取下一个触发的时间点
}
Scheduler类
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
public
class Scheduler
{ class SchedulerTimerTask extends TimerTask 
{ private SchedulerTask schedulerTask; private ScheduleIterator iterator; public SchedulerTimerTask(SchedulerTask schedulerTask,ScheduleIterator iterator) { this.schedulerTask = schedulerTask; this.iterator = iterator;
} public void run() { schedulerTask.run(); reschedule(schedulerTask, iterator); } } private final Timer timer = new Timer(); public Scheduler() { } public void cancel() { timer.cancel(); } public void schedule(SchedulerTask schedulerTask,ScheduleIterator iterator) { Date time = iterator.next(); if (time == null) { schedulerTask.cancel(); } else { synchronized(schedulerTask.lock) { if (schedulerTask.state != SchedulerTask.VIRGIN) { throw new IllegalStateException("Task already scheduled " + "or cancelled"); } schedulerTask.state = SchedulerTask.SCHEDULED; schedulerTask.timerTask = new SchedulerTimerTask(schedulerTask, iterator); timer.schedule(schedulerTask.timerTask, time); } } } private void reschedule(SchedulerTask schedulerTask,ScheduleIterator iterator) { Date time = iterator.next(); if (time == null) { schedulerTask.cancel(); } else { synchronized(schedulerTask.lock) { if (schedulerTask.state != SchedulerTask.CANCELLED) { schedulerTask.timerTask = new SchedulerTimerTask(schedulerTask, iterator); timer.schedule(schedulerTask.timerTask, time); } } } }}
SchedulerTask 类
import java.util.TimerTask;
public
abstract
class SchedulerTask implements Runnable
{//被调度器不断调度执行的任务 final Object lock = new Object(); int state = VIRGIN;//任务状态 static final int VIRGIN = 0; static final int SCHEDULED = 1; static final int CANCELLED = 2; TimerTask timerTask;//底层的定时器任务 protected SchedulerTask() { } public abstract void run();//调度任务执行的具体任务 public boolean cancel() { synchronized(lock) { if (timerTask != null) { timerTask.cancel();//取消任务 } boolean result = (state == SCHEDULED);//任务已经被调度执行 state = CANCELLED;//设置任务状态为“取消” return result; } } public long scheduledExecutionTime() { synchronized(lock) { return timerTask == null ? 0 : timerTask.scheduledExecutionTime();//任务执行时间 } }}
DailyIterator类：
import java.util.Calendar;
import java.util.Date;
public
class DailyIterator implements ScheduleIterator
{ private final int hourOfDay, minute, second; private final Calendar calendar = Calendar.getInstance(); public DailyIterator(int hourOfDay, int minute, int second) { this(hourOfDay, minute, second, new Date()); } public DailyIterator(int hourOfDay, int minute, int second, Date date) { this.hourOfDay = hourOfDay; this.minute = minute; this.second = second; calendar.setTime(date); calendar.set(Calendar.HOUR_OF_DAY, hourOfDay); calendar.set(Calendar.MINUTE, minute); calendar.set(Calendar.SECOND, second); calendar.set(Calendar.MILLISECOND, 0); if (!calendar.getTime().before(date)) { calendar.add(Calendar.DATE, -1); } } public Date next() {//获取下一个触发的时间点 calendar.add(Calendar.DATE, 1); return calendar.getTime(); }}
测试类：
import java.text.SimpleDateFormat;
import java.util.Date;
import org.tiling.scheduling.Scheduler;
import org.tiling.scheduling.SchedulerTask;
import org.tiling.scheduling.examples.iterators.DailyIterator;
public
class AlarmClock
{ private final Scheduler scheduler = new Scheduler();//调度器 private final SimpleDateFormat dateFormat = new SimpleDateFormat("dd MMM yyyy HH:mm:ss.SSS"); private final int hourOfDay, minute, second;//每天触发的时间点 public AlarmClock(int hourOfDay, int minute, int second) { this.hourOfDay = hourOfDay; this.minute = minute; this.second = second; } public void start() { scheduler.schedule(new SchedulerTask() { public void run() { soundAlarm(); } private void soundAlarm() { System.out.println("Wake up! " + "It's " + dateFormat.format(new Date())); // Start a new thread to sound an alarm } }, new DailyIterator(hourOfDay, minute, second));//通过迭代器模式迭代遍历得到后面一系列的时间点 } public static void main(String[] args) { AlarmClock alarmClock = new AlarmClock(22, 5, 0); alarmClock.start(); }}
