Re: Should loading a shared object try to fetch? (was: Should ERXEC get sharedEC automagically?)
Re: Should loading a shared object try to fetch? (was: Should ERXEC get sharedEC automagically?)
- Subject: Re: Should loading a shared object try to fetch? (was: Should ERXEC get sharedEC automagically?)
- From: Chuck Hill <email@hidden>
- Date: Wed, 22 Aug 2018 03:03:05 +0000
- Thread-topic: Should loading a shared object try to fetch? (was: Should ERXEC get sharedEC automagically?)
Assuming that we are looking at the same version of ERXGenericRecord, the NPE
is from here:
EOGlobalID gid =
editingContext.globalIDForObject(this);
if (gid.isTemporary()) {
That suggests that editingContext != this.editingContext()
In other words, that the object is registered in an editing context that is
different from the parameter to the awakeFromInsertion method. Can you check
what ECs those are? I am not sure how you would get them to be different…
Also, I see two awakeFromInsertion methods in your code:
at
cz.ocs.model.OCSEnterpriseObject.super$4$awakeFromInsertion(OCSEnterpriseObject.groovy)
and
at
cz.ocs.model.OCSEnterpriseObject.awakeFromInsertion(OCSEnterpriseObject.groovy:265)
// [*]
Or that just an artifact from using Groovy?
Chuck
From: "ocs@ocs" <email@hidden>
Date: Tuesday, August 21, 2018 at 7:05 PM
To: Chuck Hill <email@hidden>
Cc: "email@hidden" <email@hidden>
Subject: Re: Should loading a shared object try to fetch? (was: Should ERXEC
get sharedEC automagically?)
Chuck,
thanks again! I did not know that (well one could write a much bigger book than
you did with just those things I do not know...)
Nevertheless, there still must be some ugly fault of mine. When using
objectWithPrimaryKeyValue, there's the superfluous fetch, but it works.
When replaced by faultWithPrimaryKeyValue, I keep getting NPEs somewhere inside
of awakeFromInsertion — at the moment, I can't really make sense of it :( It
looks like this:
===
== about to load 110 from 348ad293 (SEC ) // first time, there's yet no SEC...
4105 [main] DEBUG NSLog - Using JDBCPlugIn
'com.webobjects.jdbcadaptor.FrontbasePlugIn' for JDBCAdaptor@2076611420
... and it is being initialised here; it fetches properly all the shared EOs ...
4110 [main] DEBUG NSLog - connecting with dictionary: {username = "";
password = "<password deleted for log>"; URL =
"jdbc:FrontBase://localhost/SBERDAT3/user=FINServis/isolation=read_committed/locking=optimistic";
}
... ... ... the proper SQL to load all the shared objects here ... ... ...
4235 [main] DEBUG NSLog - === Commit Internal Transaction
... and here's a problem; my overridden awakeFromInsertion logs this just
before a super.awakeFromInsertion:
awakeFromInsertion: <DBDFList@709f0202 PK: N NULL-EC> in
er.extensions.eof.ERXEC@348ad293
... and a log _after_ super does not happen; instead, I get this:
java.lang.Exception:
... ... ...
Caused by: java.lang.NullPointerException
at
er.extensions.eof.ERXGenericRecord.awakeFromInsertion(ERXGenericRecord.java:512)
at
cz.ocs.model.OCSEnterpriseObject.super$4$awakeFromInsertion(OCSEnterpriseObject.groovy)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)
at
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at
java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)
... groovy stuff here ...
at
cz.ocs.model.OCSEnterpriseObject.awakeFromInsertion(OCSEnterpriseObject.groovy:265)
// [*]
at
com.webobjects.eocontrol.EOEditingContext.insertObjectWithGlobalID(EOEditingContext.java:2871)
at er.extensions.eof.ERXEC.insertObjectWithGlobalID(ERXEC.java:975)
at er.extensions.eof.ERXEC$insertObjectWithGlobalID$0.call(Unknown Source)
... groovy stuff here ...
at cz.ocs.model.OCSEnterpriseObject.staticEOSVM(OCSEnterpriseObject.groovy:164)
// the faultWith... here
===
The awake code looks simply like this:
===
void awakeFromInsertion(EOEditingContext ec) {
println "awakeFromInsertion: ${this} in ${ec}" // this one happens before the
NPE
super.awakeFromInsertion(ec) // [*]
println "supered awakeFromInsertion: ${this} in ${ec}" // we do not get this far
... ... ...
===
Alas, at the moment I have no idea at all what in my code might be the culprit
:(
Thanks and all the best,
OC
On 22 Aug 2018, at 3:14 AM, Chuck Hill
<email@hidden<mailto:email@hidden>> wrote:
Yes, that makes complete sense. EOUtilities.objectWithPrimaryKeyValue is
documented to “Fetches the Enterprise Object identified by the specified
primary key value”. It will fetch. Always. It might not use the fetched
result, but you asked it to fetch so it will. The method you want is
faultWithPrimaryKeyValue. That will either resolve the object reference from
an EO already in the EC, in the shared EC, or in the snapshot cache. If all of
those fail, only then will it fetch.
And yes, the JavaDocs for faultWithPrimaryKeyValue are wrong (copied from
objectWithPrimaryKeyValue).
Chuck
From: "ocs@ocs" <email@hidden<mailto:email@hidden>>
Date: Tuesday, August 21, 2018 at 5:15 PM
To: Chuck Hill <email@hidden<mailto:email@hidden>>
Cc: "email@hidden<mailto:email@hidden>"
<email@hidden<mailto:email@hidden>>
Subject: Should loading a shared object try to fetch? (was: Should ERXEC get
sharedEC automagically?)
Even without ERXObjectStoreCoordinatorPool, there's another strange behaviour.
I happen to be loading my objects (many of which happen to be in the SEC) using
“EOUtilities.objectWithPrimaryKeyValue”.
If the object happens to be in the SEC, I get it all right, but when I switch
on SQL log, it looks like it is fetched anyway?!? I.e., something like this:
===
println "== about to load $pk from $ec.identityHashString (SEC
$ec.sharedEditingContext.identityHashString)"
def foo=ec.sharedEditingContext.objectsByEntityName[ename].find {
it.rawPrimaryKey==pk }
if (foo!=nil) println " it IS pre-loaded in SEC: $foo"
//object=EOUtilities.objectWithPrimaryKeyValue(ec,ename,pk)
object=ERXEOControlUtilities.objectWithPrimaryKeyValue(ec,ename,pk,NSArray.EmptyArray,NO,NO)
println " got $object"
===
logs out something like
===
== about to load 101 from 25673087 (SEC a7cf42f)
it IS pre-loaded in SEC: <DBDFList@3a4aadf8 PK:101 SEC:a7cf42f>
4663 [main] DEBUG NSLog - === Begin Internal Transaction
4663 [main] DEBUG NSLog - evaluateExpression:
<com.webobjects.jdbcadaptor.FrontbasePlugIn$FrontbaseExpression: "SELECT
t0."C_DESCRIPTION", t0."C_CREATION_DATE", t0."C_CREATOR_ID", t0."C_IDENTIFIER",
t0."C_CONTENT_DATA", t0."C_MODIFICATION_DATE", t0."C_TITLE", t0."C_UID" FROM
"T_DF_LIST" t0 WHERE t0."C_UID" = 101" withBindings: >
4664 [main] DEBUG NSLog - 1 row(s) processed
4665 [main] DEBUG NSLog - === Commit Internal Transaction
got <DBDFList@3a4aadf8 PK:101 SEC:a7cf42f>
===
Happens even with a
“ERXEOControlUtilities.objectWithPrimaryKeyValue(...,NSArray.EmptyArray,false,false)”
instead.
Does it make any sense? I would presume that with the desired object in the
SEC, no database roundtrip should be needed (and done) at all?
Thanks and all the best,
OC
On 21 Aug 2018, at 10:02 PM, ocs@ocs <email@hidden<mailto:email@hidden>> wrote:
Indeed! If I switch off the OSCPool, it starts to work properly.
Thanks just again!
Nevertheless, I still must be missing something of grave importance, for with
OCSPool (I use ), I would presume the SEC for the pool being currently used by
the ERXEC would load the shared objects?
It does not: the global one does automatically load the shared objects, but the
SEC-based one of ERXEC remains empty.
Note: the code in question does not run in a session context; it is performed
at launch, before the first session is created. Might that be important perhaps?
All the best,
OC
On 21 Aug 2018, at 9:42 PM, Chuck Hill
<email@hidden<mailto:email@hidden>> wrote:
Are you using the ERXObjectStoreCoordinatorPool? It keeps one SEC per pool,
not one shared globally. EOSharedEditingContext.defaultSharedEditingContext()
is the global one.
Chuck
From: "ocs@ocs" <email@hidden<mailto:email@hidden>>
Date: Tuesday, August 21, 2018 at 12:23 PM
To: Chuck Hill <email@hidden<mailto:email@hidden>>
Cc: "email@hidden<mailto:email@hidden>"
<email@hidden<mailto:email@hidden>>
Subject: Re: Should ERXEC get sharedEC automagically?
P.S. It seems ERX completely ignores the default shared EC, using its own one.
If I try e.g., this:
===
println "The default sharedEC is
${EOSharedEditingContext.defaultSharedEditingContext()}"
6.times {
def e=ERXEC.newEditingContext()
println "EC $e gets sec $e.sharedEditingContext"
}
println "The default sharedEC still is
${EOSharedEditingContext.defaultSharedEditingContext()}"
===
it looks like this:
===
The default sharedEC is com.webobjects.eocontrol.EOSharedEditingContext@26bbe604
2005 [main] INFO er.extensions.eof.ERXObjectStoreCoordinatorPool -
initializing Pool...
2008 [main] INFO er.extensions.eof.ERXObjectStoreCoordinatorPool -
initializing Pool finished
EC er.extensions.eof.ERXEC@40e32762 gets sec
com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
EC er.extensions.eof.ERXEC@7d78f3d5 gets sec
com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
EC er.extensions.eof.ERXEC@f5b6e78 gets sec
com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
EC er.extensions.eof.ERXEC@71926a36 gets sec
com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
EC er.extensions.eof.ERXEC@48976e6d gets sec
com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
EC er.extensions.eof.ERXEC@7f6874f2 gets sec
com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
The default sharedEC still is
com.webobjects.eocontrol.EOSharedEditingContext@26bbe604
===
Thanks and all the best,
OC
On 21 Aug 2018, at 9:07 PM, ocs@ocs <email@hidden<mailto:email@hidden>> wrote:
Chuck,
sorry, I did not describe the problem clearly enough...
On 21 Aug 2018, at 8:39 PM, Chuck Hill
<email@hidden<mailto:email@hidden>> wrote:
Once an EC has objects in it, its shared EC won’t get changed if a new default
is set. The notification is ignored.
Quite, but that's not the problem.
With EOEditingContext, it works like this:
(i) ec created, has no sharedEC (ec.sharedEditingContext==null)
(ii) (due to something which creates a DBContext, I believe) the default
sharedEC is initialized; it loads the shared objects, and sends the notification
(iii) ec observes the notification, and sets the default sharedEC as its own
sharedEC (for it is still empty)
(iv) now, ec fetches the objects — automatically giving shared ones from its
sharedEC, which does contain them
With ERXEC (and ERXEC.useSharedEditingContext=true), there's an important
difference:
(i) erxec created, immediately gets a sharedEC (ec.sharedEditingContext!=null).
This sharedEC differs from the default shared EC
(ii) (due to something which creates a DBContext, I believe) the default
sharedEC is initialized; it loads the shared objects, and sends the notification
(iii) erxec (although still empty) does nothing, it already has a sharedEC,
different from the default one
(iv) now, erxec fetches the objects — would automatically give shared ones from
its sharedEC, which, alas, contains nothing (the default one does).
Thanks and all the best,
OC
From: "ocs@ocs" <email@hidden<mailto:email@hidden>>
Date: Tuesday, August 21, 2018 at 11:21 AM
To: Chuck Hill <email@hidden<mailto:email@hidden>>
Cc: "email@hidden<mailto:email@hidden>"
<email@hidden<mailto:email@hidden>>
Subject: Re: Should ERXEC get sharedEC automagically?
Chuck,
On 21 Aug 2018, at 7:50 PM, Chuck Hill
<email@hidden<mailto:email@hidden>> wrote:
See er.extensions.ERXEC.useSharedEditingContext at
https://wiki.wocommunity.org/display/documentation/Explanation+of+the+default+properties+in+a+Wonder+project
Thanks a lot!
(Why on earth don't they mention this on the ERXEC documentation page? Oh,
never mind.)
Did that fix it?
Well, sort of.
It gets curiouser and curiouser — in other words, I must be doing something far
wrong.
When I set the “ERXEC.useSharedEditingContext” property to true, then
- the newly created ERXEC gets a shared editing context immediately upon
creation, not later upon receiving
DefaultSharedEditingContextWasInitializedNotification;
- and it is a different shared EC instance, not
EOSharedEditingContext.defaultSharedEditingContext()
- but it is EOSharedEditingContext.defaultSharedEditingContext() who reads in
automatically all the shared EOs
- and therefore, when fetching EOs through the ERXEC, I am still getting
non-shared ones in the ERXEC (for its own sharedEC is empty, and thus
EOSharedEditingContext.defaultSharedEditingContext is ignored).
Can you make any sense of that?
Thanks again a very big lot,
OC
On 2018-08-21, 9:43 AM, "Webobjects-dev on behalf of ocs@ocs"
<webobjects-dev-bounces+chill=email@hidden<mailto:webobjects-dev-bounces+chill=email@hidden>
on behalf of email@hidden<mailto:email@hidden>> wrote:
Hi there,
the EOEditing context doc pretty unequivocally says
===
By default, an editing context that has no shared editing context listens
for DefaultSharedEditingContextWasInitializedNotifications. If a notification
is posted while the context has no registered objects, the editing context sets
its shared editing context to the newly initialized default shared editing
context.
===
Should it apply for an ERXEC, too? I sort of inferred it would, but by my
testing, it does not seem so: an ERXEC I make (through
ERXEC.newEditingContext()) seems to adamantly stay without
sharedEditingContext, although the notification is posted all right (I have
observed it myself to be sure), and if there's a good ole EOEditingContext, it
indeed duly sets its sharedEC at the time.
Have I missed something of importance somewhere? The ERXEC documentation
does not say essentially anything of the sharedEC, far as I can say:
http://wonder.sourceforge.net/javadoc/er/extensions/ERXEC.html
In principle, I could work around the problem by setting the sharedEC to all
my ERXECs programmatically -- that works all right --, but it would be a lot of
work, with a danger I overlook something somewhere and got bit in the tender
parts by that...
Thanks,
OC
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