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From "Eric Floehr" <eflo...@boxicom.com>
Subject RE: Help: getting NPE at ObjectStoreGraphDiff.preprocess
Date Wed, 07 Mar 2007 18:40:53 GMT
Hi Mike,

Thanks...the stack trace I copied with my question had the line numbers,
I believe.  Here they are again for reference:

Exception in thread "main" java.lang.NullPointerException
	at
org.apache.cayenne.access.ObjectStoreGraphDiff.preprocess(ObjectStoreGra
phDiff.java:184)
	at
org.apache.cayenne.access.ObjectStoreGraphDiff.<init>(ObjectStoreGraphDi
ff.java:53)
	at
org.apache.cayenne.access.ObjectStore.getChanges(ObjectStore.java:496)
	at
org.apache.cayenne.access.DataContext.flushToParent(DataContext.java:120
8)
	at
org.apache.cayenne.access.DataContext.commitChanges(DataContext.java:113
0)


Specifically, line 181 in ObjectStoreGraphDiff.java is returning the
null, which then gets referenced on line 184.  Line 181 is:

Persistent object = (Persistent) objectStore.getNode(id);

The method is iterating over changes.entrySet().  There are three items
in the set.  The first has an entityName of MyType, the second of
MyCategory, and the third of MyType.  The first two complete fine, it is
the third that gives the NPE.

For reference, here is the code that causes the error:

MyType type = (MyType) context.newObject(MyType.class);
type.setObjectId(new ObjectId(MyType.class.getSimpleName(),
MyType.MYTYPE_ID_PK_COLUMN, 1));
type.setName("MyName");
MyCategory category = (MyCategory)DataObjectUtils.objectForPK(context,
MyCategory.class, 1);
type.setMyCategory(category);
context.commitChanges();

Thanks again for your help,
Eric


-----Original Message-----
From: Mike Kienenberger [mailto:mkienenb@gmail.com] 
Sent: Wednesday, March 07, 2007 11:10 AM
To: user@cayenne.apache.org
Subject: Re: Help: getting NPE at ObjectStoreGraphDiff.preprocess

Eric,

A good first step would be to get the Cayenne 2.0.2 source, and post
the relevent line numbers.   Maybe it'll be obvious once we see what's
null.

On 3/6/07, Eric Floehr <efloehr@boxicom.com> wrote:
> Hi!
>
>
>
> I am new to Cayenne, and am having some problems.  I have been able to
> populate some DB records, but when I try to set up a relationship, I
get
> an NPE on the commit.  I am using Cayenne 2.0.2.
>
>
>
> Here is the essential code (with some names changed to protect the
> innocent):
>
>
>
> MyType type = (MyType) context.newObject(MyType.class);
>
> type.setObjectId(new ObjectId(MyType.class.getSimpleName(),
> MyType.MYTYPE_ID_PK_COLUMN, 1));
>
> type.setName("MyName");
>
> MyCategory category = (MyCategory)DataObjectUtils.objectForPK(context,
> MyCategory.class, 1);
>
> type.setMyCategory(category);
>
> context.commitChanges();
>
>
>
> The MyType table has fields mytype_id (the primary key), name, and a
> mycategory_id (foreign key to the mycategory table).  I am creating a
> new "MyType" object with a mytype_id of 1, name of "MyName", and
> pointing to a Category object, that is already in the database, with a
> primary key of 1.
>
>
>
> When commitChanges() runs, I get:
>
>
>
> Exception in thread "main" java.lang.NullPointerException
>
>       at
>
org.apache.cayenne.access.ObjectStoreGraphDiff.preprocess(ObjectStoreGra
> phDiff.java:184)
>
>       at
>
org.apache.cayenne.access.ObjectStoreGraphDiff.<init>(ObjectStoreGraphDi
> ff.java:53)
>
>       at
> org.apache.cayenne.access.ObjectStore.getChanges(ObjectStore.java:496)
>
>       at
>
org.apache.cayenne.access.DataContext.flushToParent(DataContext.java:120
> 8)
>
>       at
>
org.apache.cayenne.access.DataContext.commitChanges(DataContext.java:113
> 0)
>
>       at
> com.boxicom.server.db.CreateDb.testStreamTypeAdd(CreateDb.java:96)
>
>       at com.boxicom.server.db.CreateDb.main(CreateDb.java:105)
>
>
>
> Can anyone help me determine what is going wrong?
>
>
>
> Thanks much!
>
> Eric
>
>
>
>

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