Re: Ordering guarantees for async callbacks vs watchers

2010-02-10 Thread Mahadev Konar
Hi martin,
 a call like getchildren(final String path, Watcher watcher,
ChildrenCallback cb, Object ctx)

Means that set a watch on this node for any further changes on the server. A
client will see the response to getchildren data before the above watch is
fired. 

Hope that helps.

Thanks
mahadev


On 2/10/10 6:59 PM, "Martin Traverso"  wrote:

> What are the ordering guarantees for asynchronous callbacks vs watcher
> notifications (Java API) when both are used in the same call? E.g.,
> for getChildren(final String path, Watcher watcher, ChildrenCallback cb,
> Object ctx)
> 
> Will the callback always be invoked before the watcher if there is a state
> change on the server at about the same time the call is made?
> 
> I *think* that's what's implied by the documentation, but I'm not sure I'm
> reading it right:
> 
> "All completions for asynchronous calls and watcher callbacks will be made
> in order, one at a time. The caller can do any processing they wish, but no
> other callbacks will be processed during that time." (
> http://hadoop.apache.org/zookeeper/docs/r3.2.2/zookeeperProgrammers.html#Java+
> Binding
> )
> 
> Thanks!
> 
> Martin



Ordering guarantees for async callbacks vs watchers

2010-02-10 Thread Martin Traverso
What are the ordering guarantees for asynchronous callbacks vs watcher
notifications (Java API) when both are used in the same call? E.g.,
for getChildren(final String path, Watcher watcher, ChildrenCallback cb,
Object ctx)

Will the callback always be invoked before the watcher if there is a state
change on the server at about the same time the call is made?

I *think* that's what's implied by the documentation, but I'm not sure I'm
reading it right:

"All completions for asynchronous calls and watcher callbacks will be made
in order, one at a time. The caller can do any processing they wish, but no
other callbacks will be processed during that time." (
http://hadoop.apache.org/zookeeper/docs/r3.2.2/zookeeperProgrammers.html#Java+Binding
)

Thanks!

Martin