Quartz.net官方开发指南 第二课：Jobs And Triggers
2007-08-16 20:20:00
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正如前面所提到的那样，通过实现IJob接口来使你的.NET组件可以很简单地被scheduler执行。下面是IJob接口：
 namespace Quartz {  /// <summary> /// The interface to be implemented by classes which represent a 'job' to be /// performed. /// </summary> /// <remarks> /// Instances of this interface must have a <see langword="public" /> /// no-argument constructor. <see cref="JobDataMap" /> provides a mechanism for 'instance member data' /// that may be required by some implementations of this interface. /// </remarks> /// <seealso cref="JobDetail" /> /// <seealso cref="IStatefulJob" /> /// <seealso cref="Trigger" /> /// <seealso cref="IScheduler" /> /// <author>James House</author> /// <author>Marko Lahma (.NET)</author> public interface IJob { /// <summary> /// Called by the <see cref="IScheduler" /> when a <see cref="Trigger" /> /// fires that is associated with the <see cref="IJob" />. /// </summary> /// <remarks> /// The implementation may wish to set a result object on the /// JobExecutionContext before this method exits. The result itself /// is meaningless to Quartz, but may be informative to /// <see cref="IJobListener" />s or /// <see cref="ITriggerListener" />s that are watching the job's /// execution. /// </remarks> /// <param name="context">The execution context.</param> void Execute(JobExecutionContext context); } } ILog log = LogManager.GetLogger(typeof (SimpleTriggerExample)); log.Info("------- Initializing -------------------"); // First we must get a reference to a scheduler ISchedulerFactory sf = new StdSchedulerFactory(); IScheduler sched = sf.GetScheduler(); log.Info("------- Initialization Complete --------"); log.Info("------- Scheduling Jobs ----------------"); // jobs can be scheduled before sched.start() has been called // get a "nice round" time a few seconds in the future DateTime ts = TriggerUtils.GetNextGivenSecondDate(null, 15); // job1 will only fire once at date/time "ts" JobDetail job = new JobDetail("job1", "group1", typeof (SimpleJob)); SimpleTrigger trigger = new SimpleTrigger("trigger1", "group1", ts); // schedule it to run! DateTime ft = sched.ScheduleJob(job, trigger); log.Info(string.Format("{0} will run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); // job2 will only fire once at date/time "ts" job = new JobDetail("job2", "group1", typeof (SimpleJob)); trigger = new SimpleTrigger("trigger2", "group1", "job2", "group1", ts, null, 0, 0); ft = sched.ScheduleJob((job), trigger); log.Info(string.Format("{0} will run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); // job3 will run 11 times (run once and repeat 10 more times) // job3 will repeat every 10 seconds (10000 ms) job = new JobDetail("job3", "group1", typeof (SimpleJob)); trigger = new SimpleTrigger("trigger3", "group1", "job3", "group1", ts, null, 10, 10000L); ft = sched.ScheduleJob(job, trigger); log.Info(string.Format("{0} will run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); // the same job (job3) will be scheduled by a another trigger // this time will only run every 70 seocnds (70000 ms) trigger = new SimpleTrigger("trigger3", "group2", "job3", "group1", ts, null, 2, 70000L); ft = sched.ScheduleJob(trigger); log.Info(string.Format("{0} will [also] run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); // job4 will run 6 times (run once and repeat 5 more times) // job4 will repeat every 10 seconds (10000 ms) job = new JobDetail("job4", "group1", typeof (SimpleJob)); trigger = new SimpleTrigger("trigger4", "group1", "job4", "group1", ts, null, 5, 10000L); ft = sched.ScheduleJob(job, trigger); log.Info(string.Format("{0} will run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); // job5 will run once, five minutes past "ts" (300 seconds past "ts") job = new JobDetail("job5", "group1", typeof (SimpleJob)); trigger = new SimpleTrigger("trigger5", "group1", "job5", "group1", ts.AddMilliseconds(300*1000), null, 0, 0); ft = sched.ScheduleJob(job, trigger); log.Info(string.Format("{0} will run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); // job6 will run indefinitely, every 50 seconds job = new JobDetail("job6", "group1", typeof (SimpleJob)); trigger = new SimpleTrigger("trigger6", "group1", "job6", "group1", ts, null, SimpleTrigger.REPEAT_INDEFINITELY, 50000L); ft = sched.ScheduleJob(job, trigger); log.Info(string.Format("{0} will run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); log.Info("------- Starting Scheduler ----------------"); // All of the jobs have been added to the scheduler, but none of the jobs // will run until the scheduler has been started sched.Start(); log.Info("------- Started Scheduler -----------------"); // jobs can also be scheduled after start() has been called // job7 will repeat 20 times, repeat every five minutes job = new JobDetail("job7", "group1", typeof (SimpleJob)); trigger = new SimpleTrigger("trigger7", "group1", "job7", "group1", ts, null, 20, 300000); ft = sched.ScheduleJob(job, trigger); log.Info(string.Format("{0} will run at: {1} and repeat: {2} times, every {3} seconds", job.FullName, ft.ToString("r"), trigger.RepeatCount, (trigger.RepeatInterval/1000))); // jobs can be fired directly (rather than waiting for a trigger) job = new JobDetail("job8", "group1", typeof (SimpleJob)); job.Durable = (true); sched.AddJob(job, true); log.Info("'Manually' triggering job8"); sched.TriggerJob("job8", "group1"); log.Info("------- Waiting 30 seconds --------------"); try { // wait 30 seconds to show jobs Thread.Sleep(30*1000); // executing } catch (ThreadInterruptedException) { } // jobs can be re-scheduled // job 7 will run immediately and repeat 10 times for every second log.Info("------- Rescheduling --------------------"); trigger = new SimpleTrigger("trigger7", "group1", "job7", "group1", DateTime.Now, null, 10, 1000L); NullableDateTime ft2 = sched.RescheduleJob("trigger7", "group1", trigger); if (ft2.HasValue) { log.Info("job7 rescheduled to run at: " + ft2.Value.ToString("r")); } else { log.Error("Reschedule failed, date was null"); } log.Info("------- Waiting five minutes ------------"); try { // wait five minutes to show jobs Thread.Sleep(2*1000); // executing } catch (ThreadInterruptedException) { } log.Info("------- Shutting Down ---------------------"); sched.Shutdown(true); log.Info("------- Shutdown Complete -----------------"); // display some stats about the schedule that just ran SchedulerMetaData metaData = sched.GetMetaData(); log.Info(string.Format("Executed {0} jobs.", metaData.NumJobsExecuted)); 这样，你会猜想出，当Job触发器触发时（在某个时刻），Execute (..)就被scheduler所调用。JobExecutionContext对象被传递给这个方法，它为Job实例提供了它的“运行时”环境-一个指向执行这个IJob实例的Scheduler句柄，一个指向触发该次执行的触发器的句柄，IJob的JobDetail对象以及一些其他的条目。
JobDetail对象由Quartz客户端在Job被加入到scheduler时创建。它包含了Job的各种设置属性以及一个JobDataMap对象，这个对象被用来存储给定Job类实例的状态信息。
Trigger对象被用来触发jobs的执行。你希望将任务纳入到进度，要实例化一个Trigger并且“调整”它的属性以满足你想要的进度安排。Triggers也有一个JobDataMap与之关联，这非常有利于向触发器所触发的Job传递参数。Quartz打包了很多不同类型的Trigger,但最常用的Trigge类是SimpleTrigger和CronTrigger。
SimpleTrigger用来触发只需执行一次或者在给定时间触发并且重复N次且每次执行延迟一定时间的任务。CronTrigger按照日历触发，例如“每个周五”，每个月10日中午或者10：15分。
为什么要分为Jobs和Triggers?很多任务日程管理器没有将Jobs和Triggers进行区分。一些产品中只是将“job”简单地定义为一个带有一些小任务标识的执行时间。其他产品则更像Quartz中job和trigger的联合。而开发Quartz的时候，我们决定对日程和按照日程执行的工作进行分离。（从我们的观点来看）这有很多好处。
例如：jobs可以被创建并且存储在job scheduler中，而不依赖于trigger,而且，很多triggers可以关联一个job.另外的好处就是这种“松耦合”能使与日程中的Job相关的trigger过期后重新配置这些Job,这样以后就能够重新将这些Job纳入日程而不必重新定义它们。这样就可以更改或者替换trigger而不必重新定义与之相连的job标识符。
当向Quartz scheduler中注册Jobs 和Triggers时，它们要给出标识它们的名字。Jobs 和Triggers也可以被放入“组”中。“组”对于后续维护过程中，分类管理Jobs和 |
