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Hi James,

Thanks for the quick response! I'll give your suggestions some more thought.

Thanks again!

Chris Walzl

Hi all,

I'm trying to figure out the best way to create a set of trigger(s) that can solve a schedule similar to the following:

Fire at 2PM on the 15th of every 5th month

This type of schedule was mentioned a year or two ago, and I did not see any proposed solutions for it. I know it's an obscure schedule, but it's a schedule type that Microsoft Outlook provides. I'm pretty sure, based on my own investigation, and a previous post to this message list, that it can not be solved with just a CronTrigger or SimpleTrigger alone.

So how do I solve this? Do I create a simpler trigger that fires more often, and then bury some additional logic in the job? Do I write my own trigger implementation(yikes!)? Any ideas, or thoughts? I'd appreciate any help!

For reference, here is what James House said in that previous posting:

"

No, you won't be able to do it with a single trigger - at least not with a trigger of a type that ships with Quartz out of the box.

SimpleTrigger could handle it if it was always N days between firings, but because some months have more days than others, it won't work for keeping the trigger on the same day of the month.

CronTrigger can handle the 15th of every month, or every other month, or every third, fourth, or sixth month. It is because you have an interval that does not even divide 12 that you have the problem. The "1/5" notation means "turn the trigger on for every fifth month in the set of months, starting with month 1" - which yields month 1, 6 and 11. Of course as the year ends, you then only get two month gap between firings in month 11 and month 1. This works out fine as I said if you have an interval that can evenly factor 12.

You're the first one I can recall hearing of in the 7 years of Quartz to need such an odd schedule -- few business cycles are occur every 5th month. Though I do recall someone once had the same problem for the minute position of the expression, because they wanted the trigger to fire every 17th minute, which does not evenly divide 60. Luckily for them, "every 17 minutes" can be easily accomplished with SimpleTrigger.

james
"

Thanks again!

Chris

great reply, thanks. I think concurrent should do the trick.

Seems like you should just be able to use a shared root between the two. One of our guys recently did a demo where he shared a model between a Swing App and a Geronimo web app.

actually let me slightly rephrase....

What i really want is the posts collection to be transiant to terracotta, but still want the values in the posts collection to be passed to the worker thread, so that they are still accessible but not shared across all the clusters. If I mark the collection as transient, i have to re-query and fetch these values, but if i mark them as shared, they are subject to terracotta locking which i dont want either.

Hi Anonymous,

It's difficult to answer your question w/o at least a copy of the tc-config.xml. Ideally, it would be useful to have a glance at the code. I'll send you a private message with my email. Feel free to forward the information to me at that email address.

Gordon

I have implemented a master worker pattern, where the master is queuing up objects of type Blog, each blog instance has a collection of posts. Each worker thread receives a Blog instance for processing.

Currently my worker threads are blocking on blog.getPosts() (returns the the collection of posts for that blog). I'm guessing I have some kind of mistake in my tc-config file and wondering the following:

How can I tell terracotta that the entries property shouldnt be locking or be shared across the different clusters, since only the worker dealing with the Blog instance cares about the entries collection.

any help much appreciated....

Hi:

I have a HA server configuration. What will happen in the case where say the machine in which the passive server is running crashes and cannot be restarted. My questions are :

1. Can I move the Passive server to a new machine. If so can the new Active - Passive IP configuration be updated dynamically in the configuration.

2. What is the impact on the client in this case. Am I forced to restart them to pick this new Passive server, since it does not know about it.

3. In a production setup where I have 20 JVMs connected to a terracotta server, the last thing I want to do is having to restart all the 20 JVMs. Is there any crash use case in which I will be forced to do this.

4. Can I configure only 1 Passive server or can it be > 1.

Thanks

Sriram C

Thanks Gordon for your valuable information, now let me tell you the scenario where we are planning to fit TerraCotta, just inform me whether it is ideally correct or not,

We are using J2EE based web application using Struts which supports a variety of presentation layers, including JSP, XML/XSLT, Java Server Faces (JSF), then we are using a Multiplexer to transfer the data from the web application server to the datacenter server, which maintains the persistancy with the datacenter server.

Can we think of using, TerraCotta instead of MULTIPLEXER to maintain the clustering with the datacenter server?