# The Quartz API

The key interfaces and classes of the Quartz API are:

Type
IScheduler the main API for interacting with the scheduler
IJob an interface to be implemented by components that you wish to have executed by the scheduler
IJobDetail used to define instances of Jobs
ITrigger a component that defines the schedule upon which a given Job will be executed, job can have multiple associated triggers
JobBuilder used to define/build JobDetail instances, which define instances of Jobs
TriggerBuilder used to define/build Trigger instances
SchedulerBuilder used to define/build scheduler instances, requires Quartz 3.1 or later

In this tutorial for readability's sake following terms are used interchangeably: IScheduler and Scheduler, IJob and Job, IJobDetail and JobDetail, ITrigger and Trigger.

A Scheduler's life-cycle is bounded by it's creation, via a SchedulerFactory and a call to its Shutdown() method. Once created the IScheduler interface can be used add, remove, and list Jobs and Triggers, and perform other scheduling-related operations (such as pausing a trigger). However, the Scheduler will not actually act on any triggers (execute jobs) until it has been started with the Start() method, as shown in Lesson 1.

Quartz provides "builder" classes that define a Domain Specific Language (or DSL, also sometimes referred to as a "fluent interface"). In the previous lesson you saw an example of it, which we present a portion of here again:

// define the job and tie it to our HelloJob class
IJobDetail job = JobBuilder.Create<HelloJob>()
    .WithIdentity(name: "myJob", group: "group1")
    .Build();
    
// Trigger the job to run now, and then every 40 seconds
ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity(name: "myTrigger", group: "group1")
    .StartNow()
    .WithSimpleSchedule(x => x
        .WithIntervalInSeconds(40)
        .RepeatForever())            
    .Build();

var sched = scheduleFactory.GetScheduler();

// Tell Quartz to schedule the job using our trigger
await sched.ScheduleJob(job, trigger);

The block of code that builds the job definition is using JobBuilder to create the IJobDetail. Likewise, the block of code that builds the trigger is using TriggerBuilder's fluent interface to the trigger.

Possible schedule extension methods are:

  • WithCalendarIntervalSchedule
  • WithCronSchedule
  • WithDailyTimeIntervalSchedule
  • WithSimpleSchedule

The DateBuilder type contains various methods for easily constructing DateTimeOffset instances for particular points in time (such as a date that represents the next even hour - or in other words 10:00:00 if it is currently 9:43:27).