This may be just a trivial coding sequence problem Jeff.
Why not post your whole Runnable (or Callable) class so we can see
what you are doing ?
On Aug 4, 2008, at 12:01 AM, Jeff Schmitz wrote:
Hello,
Continuing on with trying to access EOs in a background thread, I'm
trying to give the background thread its own
EOObjectStoreCoordinator. To create a new EOObjectStoreCoordinator,
I'm using the following code:
EOObjectStoreCoordinator parentObjectStore = new
EOObjectStoreCoordinator();
EOEditingContext threadEditingContext = new
EOEditingContext(parentObjectStore);
However, when I try to fetch something into the threadEditingContext
using one of the static "fetch" functions, I get an error:
INFO er.transaction.adaptor.Exceptions - Database Exception
occured: java.lang.IllegalStateException: Attempt to access an EO
that has either not been inserted into any EOEditingContext or its
EOEditingContext has already been disposed
Exception in thread "updateResults" java.lang.IllegalStateException:
Attempt to access an EO that has either not been inserted into any
EOEditingContext or its EOEditingContext has already been disposed
at
com.webobjects.eocontrol.EOCustomObject.willRead(EOCustomObject.java:
1158)
I kind of thought the static fetch operations were a way to insert
objects into EC's in the first place, so I'm a little confused about
the error. Is there something extra I need to do because its not
the default editing context?
below is more info on the fetch call I'm making if you'd want to
take a look. This is what I do after creating the
threadEditingContext...
try {
threadEditingContext.lock();
EOQualifier poolQual = Pool.POOL_TYPE.eq(Constants.FULLPOOL);
NSArray<EOSortOrdering> poolOrder = new NSArray<EOSortOrdering>(
new EOSortOrdering(Pool.NAME_KEY,
EOSortOrdering.CompareAscending)); // Sort
return Pool.fetchPools(threadEditingContext, poolQual, poolOrder);
// Below is the fetchPools function generated by the EOGenerator:
public static NSArray<Pool> fetchPools(EOEditingContext
editingContext, EOQualifier qualifier, NSArray<EOSortOrdering>
sortOrderings) {
EOFetchSpecification fetchSpec = new
EOFetchSpecification(_Pool.ENTITY_NAME, qualifier, sortOrderings);
fetchSpec.setIsDeep(true);
NSArray<Pool> eoObjects =
(NSArray
<Pool>)editingContext.objectsWithFetchSpecification(fetchSpec);
return eoObjects;
}
The error actually occurs on:
NSArray<Pool> eoObjects =
(NSArray
<Pool>)editingContext.objectsWithFetchSpecification(fetchSpec);
On Jul 30, 2008, at 8:25 AM, Kieran Kelleher wrote:
I have an app that does very long tasks like this a few times a
week. The tasks I have a *very* EOF intensive, as in hammering the
database usually for a very long time (4 to 24 hours)
Here is approach I use:
Create a Callable (or Runnable) class for the task.
Create setters/getters for any initial variables you need to pass
in. For EnterpriseObjects, just pass in the EOGlobalIDs, not the
objects themselves.
In the task method itself:
- Create a new ObjectStoreCoordinator (use Wonder OSC
synchronization if you want changes to propogate)
- Create any editing contexts using that single task OSC as a parent
- lock and unlock your ec's manually when working with them
- depending on how much EO's you are fiddling with, memory
management can be challenging, so recycling ec's, and, dare I say
it, resorting to checking available memory and forcing garbage
collection when memory almost exhausted (some will cringe at this,
but extreme EOF just sucks memory and does not let go fast
enough ... depending on the conditions)
Tips
- Surround the task with a try/catch to get any errors
- Send an email to the user (if user initiated), or admin (if
necessary) notifying them of success, failure or error when task is
done (or error is thrown).
- Using log4j smtp appender for ERROR level is good too to ensure
errors in anonymous tasks are alerted to admin/devs promptly.
On Jul 30, 2008, at 12:23 AM, Jeff Schmitz wrote:
Hello,
I have the need to kick off a VERY long (i.e. possibly up to 8-10
hour) background task that before it's through fetches most of the
contents of the database (via EO's of course) and performs
calculations on the data and saves the calculated values back to
the EOs many times during the process. And oh, I'd like to have
the results available to the rest of my app as they are saved by
the background task.
Currently btw, I do this with a java thread and don't really use
EOs, and I just return a page immediately after the thread is
kicked off, i.e. I don't really care about a status page reloading
for 8 hours as I'm the only user that actually kicks off this
process.
My first question is, now that I'm using EOs throughout my app
(including the background process) is there any reason to use the
WOLongResponsePage if I still don't care about the status page?
If so, there seems to be a dearth of information on exactly how to
use such a component. All I can really find is a very terse API
doc, and a few mentions of its existance on the wiki. Any
examples out there anywhere?
I'll save my context locking and memory flushing questions until
after I've researched the subject a little more. From what I can
tell though, I'll want to create a new editing context for the
background thread (not sure about needing an independent Object
store coordinator for the background process, but I don't think
so), so that's a start.
Finally, anything in project Wonder that can help me? I did run
across this:
http://webobjects.mdimension.com/wonder/api/er/extensions/concurrency/class-use/ERXLongResponseTask.html#er.extensions.concurrency
but again, very terse docs.
Thanks,
Jeff
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