Quartz.net官方开发指南 第七课 : TriggerListeners和JobListeners

监听器是在scheduler事件发生时能够执行动作的对象。可以看出，TriggerListeners接收与triggers相关的事件，而JobListeners则接收与Job相关的事件。

Trigger相关的事件包括：trigger触发、trigger未触发，以及trigger完成（由trigger触发的任务被完成）。

/// <summary>

     /// The interface to be implemented by classes that want to be informed when a

     /// <see cref="Trigger" /> fires. In general, applications that use a

     /// <see cref="IScheduler" /> will not have use for this mechanism.

     /// </summary>

     /// <seealso cref="IScheduler" />

     /// <seealso cref="Trigger" />

     /// <seealso cref="IJobListener" />

     /// <seealso cref="JobExecutionContext" />

     /// <author>James House</author>

     public interface ITriggerListener

     {

         /// <summary>

         /// Get the name of the <see cref="ITriggerListener" />.

         /// </summary>

         string Name { get; }

 

         /// <summary>

         /// Called by the <see cref="IScheduler" /> when a <see cref="Trigger" />

         /// has fired, and it's associated <see cref="JobDetail" />

         /// is about to be executed.

         /// <p>

         /// It is called before the <see cref="VetoJobExecution" /> method of this

         /// interface.

         /// </p>

         /// </summary>

         /// <param name="trigger">The <see cref="Trigger" /> that has fired.</param>

         /// <param name="context">

         ///     The <see cref="JobExecutionContext" /> that will be passed to the <see cref="IJob" />'s<see cref="IJob.Execute" /> method.

         /// </param>

         void TriggerFired(Trigger trigger, JobExecutionContext context);

 

         /// <summary>

         /// Called by the <see cref="IScheduler" /> when a <see cref="Trigger" />

         /// has fired, and it's associated <see cref="JobDetail" />

         /// is about to be executed.

         /// <p>

         /// It is called after the <see cref="TriggerFired" /> method of this

         /// interface.

         /// </p>

         /// </summary>

         /// <param name="trigger">The <see cref="Trigger" /> that has fired.</param>

         /// <param name="context">

         /// The <see cref="JobExecutionContext" /> that will be passed to

         /// the <see cref="IJob" />'s<see cref="IJob.Execute" /> method.

         /// </param>

         bool VetoJobExecution(Trigger trigger, JobExecutionContext context);

 

 

         /// <summary>

         /// Called by the <see cref="IScheduler" /> when a <see cref="Trigger" />

         /// has misfired.

         /// <p>

         /// Consideration should be given to how much time is spent in this method,

         /// as it will affect all triggers that are misfiring.  If you have lots

         /// of triggers misfiring at once, it could be an issue it this method

         /// does a lot.

         /// </p>

         /// </summary>

         /// <param name="trigger">The <see cref="Trigger" /> that has misfired.</param>

         void TriggerMisfired(Trigger trigger);

 

         /// <summary>

         /// Called by the <see cref="IScheduler" /> when a <see cref="Trigger" />

         /// has fired, it's associated <see cref="JobDetail" />

         /// has been executed, and it's <see cref="Trigger.Triggered" /> method has been

         /// called.

         /// </summary>

         /// <param name="trigger">The <see cref="Trigger" /> that was fired.</param>

         /// <param name="context">

         /// The <see cref="JobExecutionContext" /> that was passed to the

         /// <see cref="IJob" />'s<see cref="IJob.Execute" /> method.

         /// </param>

         /// <param name="triggerInstructionCode">

         /// The result of the call on the <see cref="Trigger" />'s<see cref="Trigger.Triggered" />  method.

         /// </param>

         void TriggerComplete(Trigger trigger, JobExecutionContext context, SchedulerInstruction triggerInstructionCode);

}

与任务相关的事件包括：即将被执行的任务的通知和任务已经执行完毕的通知。

The.JobListener Interface

/// <summary>

     /// The interface to be implemented by classes that want to be informed when a

     /// <see cref="JobDetail" /> executes. In general,  applications that use a

     /// <see cref="IScheduler" /> will not have use for this mechanism.

     /// </summary>

     /// <seealso cref="IScheduler" />

     /// <seealso cref="IJob" />

     /// <seealso cref="JobExecutionContext" />

     /// <seealso cref="JobExecutionException" />

     /// <seealso cref="ITriggerListener" />

     /// <author>James House</author>

     public interface IJobListener

     {

         /// <summary>

         /// Get the name of the <see cref="IJobListener" />.

         /// </summary>

         string Name { get; }

 

         /// <summary>

         /// Called by the <see cref="IScheduler" /> when a <see cref="JobDetail" />

         /// is about to be executed (an associated <see cref="Trigger" />

         /// has occured).

         /// <p>

         /// This method will not be invoked if the execution of the Job was vetoed

         /// by a <see cref="ITriggerListener" />.

         /// </p>

         /// </summary>

         /// <seealso cref="JobExecutionVetoed(JobExecutionContext)" />

         void JobToBeExecuted(JobExecutionContext context);

 

         /// <summary>

         /// Called by the <see cref="IScheduler" /> when a <see cref="JobDetail" />

         /// was about to be executed (an associated <see cref="Trigger" />

          /// has occured), but a <see cref="ITriggerListener" /> vetoed it's

         /// execution.

         /// </summary>

         /// <seealso cref="JobToBeExecuted(JobExecutionContext)" />

         void JobExecutionVetoed(JobExecutionContext context);

 

 

         /// <summary>

         /// Called by the <see cref="IScheduler" /> after a <see cref="JobDetail" />

         /// has been executed, and be for the associated <see cref="Trigger" />'s

         /// <see cref="Trigger.Triggered" /> method has been called.

         /// </summary>

         void JobWasExecuted(JobExecutionContext context, JobExecutionException jobException);

     }

使用你自定义的监听器

创建监听器很简单，创建一个实现Quartz.ITriggerListener或（和）Quartz.IJobListener的接口。监听器然后在执行的时候注册到scheduler中，而且必须给定一个名字（或者，它们必须通过他们的Name属性来介绍自己）。监听器可以被注册为“全局”的或者“非全局”。“全局”监听器接收所有triggers/jobs产生的事件，而“非全局”监听器只接受那些通过TriggerListenerNames属性 或 JobListenerNames()方法显式指定监听器名的triggers/jobs所产生的事件。

正如上面所说的那样，监听器在运行时向scheduler注册，并且不被存储在jobs 和triggers的JobStore中。Jobs和Trigger只存储了与他们相关的监听器的名字。因此，每次应用运行的时候，都需要向scheduler重新注册监听器。

 

向 Scheduler中加入一个JobListener

scheduler.AddGlobalJobListener(myJobListener);

或者

scheduler.AddJobListener(myJobListener);

Quartz的大多数用户不使用监听器，但是当应用需要创建事件通知而Job本身不能显式通知应用，则使用监听器非常方便。