[JNDI and Naming] - @Depends not supported in Jboss AS 4.2.2 ?
by Aurélien Lansmanne
Aurélien Lansmanne [http://community.jboss.org/people/alansmanne] created the discussion
"@Depends not supported in Jboss AS 4.2.2 ?"
To view the discussion, visit: http://community.jboss.org/message/583545#583545
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Hello,
I've got a problem that seems to have already been solved on these forums... but the solution doesn't work for me.
I have a Queue and a simple MDB that implements MessageDrivenBean, MessageListener.
Sometimes, when the server is restarted, the queue starts "too early" and crash, because most of the EJBs are not yet deployed.
So, I've tried to add
@Depends({
"jboss.j2ee:ear=myEar.ear,jar=myrJar-ejb.jar,name=MyBean,service=EJB3",
"....",
})
at the beginning of my MDB class. But when I restart Jboss, I see that the MDB is still deployed first (actually second) before most EJBs...
I've even try to put
@Depends({
"I hope that my wrong syntax will crash at deployment !!!"
})
But nothing happenned... and the MDB was again deployed "first".
I'm using Jboss 4.2.2. I'm can't upgrade to Jboss 5, and start to plan a full switch to Quartz instead of JMS if I can't resolve this problem...
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15 years, 2 months
[jBPM] - jBPM 5 in JBoss 5/6 appserver - start and resume
by Brian Wallis
Brian Wallis [http://community.jboss.org/people/bwallis42] created the discussion
"jBPM 5 in JBoss 5/6 appserver - start and resume"
To view the discussion, visit: http://community.jboss.org/message/583477#583477
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I'm wondering what the best way to initialise/launch drools flow in an appserver would be. I need to be able to support persistent workflows with transactions so that if I kill the appserver I can restart back to where I was. Long term, cluster failover (which is a similar requirement) would also be required.
I suspect that I should probably use some sort of ejb (stateless session bean or message driven bean) that initialises or resumes the process instances in the ejbCreate() method (since I believe using an ejb can help me support cluster failover as well).
How do you resume a bunch of persisted workflows? They would all either be waiting on an event, the presence of a fact in their session or a return from a call out to a work item (either a domain specific node or a human task).
When you restart, how do you recover the old session objects? Do you create and load a new KnowledgeBase? If the session is persisted I suppose there must be a hibernate query I can make to find all the existing instances. What do I do with them then?
I'm actuallly struggling working out what the right question is :-)
In short, I want to use jBPM in the JBoss appserver and have workflow instances reliably span restarts.
thanks.
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15 years, 2 months
[JBoss Cache] - How to handle an object's expiry in cache
by Prashanth ga
Prashanth ga [http://community.jboss.org/people/gaprashanth] created the discussion
"How to handle an object's expiry in cache"
To view the discussion, visit: http://community.jboss.org/message/583576#583576
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We understand from the Jboss Cache userguide that either the object can be made to be available in the persistent store all the time as a superset because of passivation OR available in the persistence store only on using eviction along with class loading, passivation. Also eviction allows us to make the efficient use of memory by configuring timeToLive or maxAge kind of parameters which evict the obejcts and persist to the store while the memory is overloaded.
This means, the object is always available either from the memory or the persistent store. But how does the object permanently removed from the cache ( either memory or store). Do we need to have an additional algorithm to clean up the objects from the persistemt stores on some interval of expiry. Is there a way we can avoid this and just be able to achieve with the configurations of Jboss cache ?
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15 years, 2 months
[JBoss Cache] - High availability question on Jboss cache
by Prashanth rao
Prashanth rao [http://community.jboss.org/people/gaprashanth] created the discussion
"High availability question on Jboss cache"
To view the discussion, visit: http://community.jboss.org/message/583573#583573
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We are having an all active node cluster where each node can receive requests for reading data and is expected to return identical data all the time. Now there is a requirement to introduce a caching framework which should fit into our architecture without changing the current design.
While we investigate Jboss cache arhictecture, we understand that it provides in-memory cache but also persistense based on some configurations with eviction and class loading. This suits our need of using eviction for the efficient use of memory and persisting only on memory overload. But we are having a requirement on deleting the cached data (permanetly) on its expiry. We may have to impelement a supplementary feature to implement this and this is not the issue.
We are evaluating the different cache loading techniques like shared class loaders, class loaders with each node having its own persistent store etc. But as made clear earlier, we also need to combine eviction along with class loading as we need to make best use of memory. Our concern is selecting the best class loading technique which suits our architecture.
A) If shared class loading is used,
if the object is evicted at different intervals from the different nodes of the cluster, whether the object passivated from node will be overwriiten from the other node ? But if this ok as the objects evicted/passivated are all same across the nodes due to replication ( used with synchronous option)
If one node is restarted, should it load the state from other node because it cant just rely on the persistent store as the other node can be ahead of the persistent store.
B) If we use different persistent stores for each node,
If the objects are evicted at different intervals from the different nodes of the cluster, we can assume that the objects will go into separate persistence stores. But again if a node is restarted, it has to load the entire state from the memory of other node and not its persistence store as the memory always has the actual data if used with eviction ?
If the persistent store one node is down, what happen to the requests on that node. Whether the object is automatically loaded from other nodes and returned back as well as updating the local cache?
Also one more concern is on the concurrent writes to the same object across the cluster. We understand that Jboss cache supports 2 phase commit, where the object is locked for writes on other nodes while it is being done on some node.
Please provide us some inputs at the earliest as it is URGENT.
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15 years, 2 months