Quartz and Quarkus - java

I am trying to use Quartz with Quarkus.
In the guide: https://quarkus.io/guides/quartz
They create an application scoped TaskBean, that creates a job instance, that when executed
does nothing but persisting an empty Task entity.
This IMHO doesn't look very clean and doesn't help much either a far as I understand it.
I am rather trying to follow a more default setup of Quartz - so I have create a "classical" Job that is supposed to do the work - and I added this to the scheduler. All working fine. Now I just need to inject a service into this job, something similar to:
http://vijaykiran.com/2013/01/a-quick-way-to-integrate-seam3-cdi-and-quartz-jobs/
Has anyone here possibly done this for Quarkus before?

At this point, Quarkus does not support injection into Quartz Jobs - based on my request a patch is on the way. In the meantime, you can directly retrieve an instance from Arc like this: Arc.container().instance(YourClass.class).get();

Related

Clustered #schedule annotations in Spring

My codebase currently uses a crontab-like quartz.properties file to define a series of jobs in our Spring web app. Our quartz config currently looks like:
org.quartz.scheduler.instanceId=AUTO
org.quartz.scheduler.jmx.export=true
org.quartz.threadPool.class=org.quartz.simpl.SimpleThreadPool
org.quartz.threadPool.threadCount=20
org.quartz.jobStore.class = org.quartz.impl.jdbcjobstore.JobStoreTX
org.quartz.jobStore.misfireThreshold=6000000
org.quartz.jobStore.isClustered=true
org.quartz.jobStore.dataSource=dataSourceConnectionProvider
I've recently become enamored of Spring's #scheduled annotation and would really like to take advantage of it. There are plenty of instances where we have some job bean that essentially wraps a single method of a service -- the annotations seem like they'd remove a lot of boilerplate and more our code more legible as a result.
However, I can't figure out how I could get the same guarantees from Spring's scheduling that we do from vanilla quartz right now. That is, setting isClustered=true and the job store implementation to use a backing database enables us to guarantee that our jobs run once per cluster without doing something unpleasant like declaring a master node and checking hostnames -- which isn't even a good guarantee for us, since we have a variable number of nodes. Nonetheless, it seems like it should be possible -- Spring's scheduling is obviously very aware of Quartz, and I have to imagine that there's a way to implement a TaskScheduler that would provide these guarantees.

Scheduling tasks in Java/Spring

There is a requirement in the project that will have a scheduled task that will do some job.
The project is Spring based and the scheduled job will be part of the application war.I have
never implemented this kind of functionality before.
I have heard of Quartz. Also, I read somewhere that Spring provides some functionality to schedule tasks. So, I was thinking if I am already using Spring then why to go for some other API(Quartz).
I am not sure which one to use? what will be the pros/cons of one over another?
Please suggest what will be the best way to approach my requirement.
I have used Spring's Task execution and scheduling - http://static.springsource.org/spring/docs/3.0.x/reference/scheduling.html

Running scheduled methods on tomcat

I am trying to set up a method that will be automatically run by the server at a specific time. For instance, a method that sends out emails to contacts every Friday at 9.00 am. I have seen methods that are run when the server is first started and was wondering if what I want to do is possible. If it is possible, can someone point me to where I can start reading up how to do this. Any help will be highly appreciated.
There is an excellent library quartz which can help you create scheduled tasks within your application. See e.g., the Job Scheduling in Java guide by o'reilly.
If you really want to do it manually (and not use specific tools like Quartz), you could use a Timer, which would be created when the application is deployed and canceled when the application is destroyed, using a ServletContextListener declared in your web.xml.
Be prepared for additional complexity if your application is clustered on multiple servers, though.
I also recommend using Quartz as Johan already suggested, it is a well-established solution for job scheduling in Java applications and also allows for central job storage in a database and clustering of multiple Tomcat instances.
In case your web application uses the Spring Framework, you could instead use the built-in scheduling support instead.

How to use Quartz with EJB3?

I want to be able to :
define different jobs and triggers.
modify the expirations dates and intervals on demand
pause or cancel an execution (trigger)
the jobs would be ejbs or call ejbs and i would want to manage everything from the website (the user will have to define the executions)
So i looked at the timerservice, timerobjects, timer and timerhandle. But i think it can't answer to all my needs
Quartz, on the other hand, allows me to do every thing that i want, but i haven't the slightest clue on how to integrate this into my jboss.
I read that quartz uses its own threadpool, and i don't know how to handle all this.
I use Jboss Seam in my project, but the seam/quartz integration is very limited (or the documentation is) and not 100% safe (seen on their forum : 'run forever' tasks end after only a few weeks)
If someone managed to integrate a good scheduler into his application server (jboss is a plus) and could give me directions, advices, or even code snippets, i would be thrilled.
Thanks in advance.
I have some experience integrating Quartz into a Weblogic (no jboss experience, sorry) application server. Quartz has a built in listener class that will be called upon server startup (per J2EE specs) that automatically configure the Quartz scheduler. Then in another startup class you can retrieve that scheduler, add jobs and begin serving those jobs.
You generally don't need to worry about the threadpool, Quartz can handle all this itself if you want it too. It gets its information from a properties files on startup that you can define or use the default one that comes with quartz. I have been using the default because it works for my purposes.
As far as defining jobs, you create your job classes and call your ejbs from there. It is rather very simple.
For your reading pleasure:
All Quartz documentation
Quartz JavaDoc
Cookbook containing lots of code snippets
Hope that's enough to get you started!
Great news! JBoss has a built-in scheduler already.
Since the EJB 2.0 specification included running stateless session beans and MDBs at scheduled intervals, all application servers have included this capability for some time now.
Here is an example of configuring JBoss to run a class using its built-in scheduler:
http://www.jboss.org/community/wiki/Scheduler
The best part about JBoss' implementation is that it is based on the MBean specification, which means that you can create/update/delete scheduled tasks at runtime.
Ok, i am sorry, i found in the sources of Jboss Seam just what i needed :
QuartzDispatcher to create QuartzTriggerHandle wich fires seam event at specified time and date and is manually pausable, resumable and stoppable. I use an #observer on the method i wanted to execute.
It's simple, and it works so far.
As pointed out by Poindexter, the Quartz documentation has nice starting points: Tutorial for Developing with Quartz, Examples of Usage, Cook Book (Quick How-Tos in the form of code examples), etc.
The What Is Quartz article is really good too (even if a bit old now).
For integration with JBoss, maybe have a look at How to configure a Quartz service on JBoss Wiki.

Java – Create a workflow in Quartz

I am considering using the Quartz framework to schedule the run of several hundred jobs.
According to their API, jobs can be scheduled to run at certain moments in time but not to run one after the other (and stop a chain of jobs if one fails).
The only recommended methods I was able to find are:
Using a listener which notices the completion of a job and schedule the next trigger to fire (how to coordinate this?)
Each job will receive a parameter containing the next job to run and, after completing the actual work, schedule its run. (Cooperative)
Do you know a better method to create a workflow of jobs in Quartz?
Can you recommend other methods/framework for implementing a workflow in Java ?
EDITED: In the meantime I found out about OSWorkflow which appears to be a good match for what I need. It appears that what I need to implement is a "Sequence Pattern".
When Quartz documentation talks about "Job", it is referring to a class implementing the "Job" Interface, which is really just any class with an "execute" method that takes in the Quartz Context object. When creating this implementation you can really do whatever you want.
You could create an implementation of the Quartz Job Interface which simply calls all the jobs in your workflow in series, and throws a JobExecutionException exception on failure.
It sounds to me like you want Quartz to schedule the first job, and chain everything off that.
Have you looked at encapsulating each task using the Command Pattern, and linking them together ?
I've worked on a project called Dynamic Task Scheduler that use Quartz to execute job chains implementing a simple workflow in a fault-tolerant way (definied in XML format).
Take a look at http://sourceforge.net/projects/dynatasksched/
The project is beta, but I think it can gives you some ideas to start..
Hope it's useful!
For job chaining support for Quartz, you may want to check the QuartzDesk project that I have been involved in. In version 2.0. we have added a powerful job chaining engine that enables you to orchestrate your Quartz jobs without the need to modify your application code.
The engine takes care of propagating the job execution result and other parameters from the source job to the chained target job.
QuartzDesk comes with a GUI that allows you to dynamically update your job chains without disrupting your application.

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