RE: ClassCastException in pcReplaceField
Hey Russel, I just added the Comparable implementation, and I hope this will solve the problem. Thanks, Udi -- View this message in context: http://n2.nabble.com/ClassCastException-in-pcReplaceField-tp4392185p4459284.html Sent from the OpenJPA Users mailing list archive at Nabble.com.
RE: ClassCastException in pcReplaceField
Honestly, you are probably correct in that all you need is a hashCode and equals for a Set. I guess the real question is, what implementation of Set is being returned by OpenJPA? If it is a TreeSet (most common), then we are on the same page since TreeSet is an implementation of an ordered collection with the following hierarchy. Set - SortedSet - NavigableSet - TreeSet I guess I am saying that you would need to use Comparable because I have not used any of the other implementations and TreeSet is the most common. -Original Message- From: craig.russ...@sun.com [mailto:craig.russ...@sun.com] Sent: Thursday, January 21, 2010 9:45 PM To: users@openjpa.apache.org Subject: Re: ClassCastException in pcReplaceField Hi, On Jan 21, 2010, at 7:23 PM, Russell Collins wrote: While the initial thought is that the equals() method would work, the specification for Set requires a compareTo method be present by implementing the Comparable interface. This is not my understanding. Set requires only hashCode and equals. Ordered collections (e.g. TreeSet) require the elements to implement Comparable or to have a Comparator specified at creation. Maybe we're reading different parts of the spec... Craig Craig L Russell Architect, Sun Java Enterprise System http://db.apache.org/jdo 408 276-5638 mailto:craig.russ...@sun.com P.S. A good JDO? O, Gasp! CONFIDENTIALITY NOTICE: The information contained in this electronic mail (email) transmission (including attachments), is intended by MCLANE ADVANCED TECHNOLOGIES for the use of the named individual or entity to which it is addressed and may contain information that is privileged, confidential and/or protected as a trade secret. It is not intended for transmission to, or receipt by, any individual or entity other than the named addressee(s). If you have received this email in error, please delete it (including attachments) and any copies thereof without printing, copying or forwarding it, and notify the sender of the error by email reply immediately.
Re: ClassCastException in pcReplaceField
Hi, On Jan 21, 2010, at 7:23 PM, Russell Collins wrote: While the initial thought is that the equals() method would work, the specification for Set requires a compareTo method be present by implementing the Comparable interface. This is not my understanding. Set requires only hashCode and equals. Ordered collections (e.g. TreeSet) require the elements to implement Comparable or to have a Comparator specified at creation. Maybe we're reading different parts of the spec... Craig Craig L Russell Architect, Sun Java Enterprise System http://db.apache.org/jdo 408 276-5638 mailto:craig.russ...@sun.com P.S. A good JDO? O, Gasp!
RE: ClassCastException in pcReplaceField
Based on the code that has been provided I am making the assumption that you are mapping your OneToMany to a Set collection. If this is the case, a Set collection will not allow duplicates. In order to check for duplicates, an object that is getting placed in the Set needs to show how it is unique. Therefore the objects that are going into the Set collection need to implement the Comparable (Sorry about IComparable) interface to be inserted. In this case, you would need object B to implement the Comparable interface. You would not need object A to implement Comparable as the comparisons are done on the instances of object B. If you are still getting cast errors, then it is probably something else. You could also try changing the Set collection type to a List to see if you get this error and you would not need to implement the Comparable interface. Remember that a List collection can contain duplicates. -Original Message- From: Udi [mailto:saba...@gmail.com] Sent: Sunday, January 17, 2010 1:07 AM To: users@openjpa.apache.org Subject: RE: ClassCastException in pcReplaceField P.S. - I forgot to mention that I'm enhanching at runtime using javaagent. -- View this message in context: http://n2.nabble.com/ClassCastException-in-pcReplaceField-tp4392185p4407523.html Sent from the OpenJPA Users mailing list archive at Nabble.com. CONFIDENTIALITY NOTICE: The information contained in this electronic mail (email) transmission (including attachments), is intended by MCLANE ADVANCED TECHNOLOGIES for the use of the named individual or entity to which it is addressed and may contain information that is privileged, confidential and/or protected as a trade secret. It is not intended for transmission to, or receipt by, any individual or entity other than the named addressee(s). If you have received this email in error, please delete it (including attachments) and any copies thereof without printing, copying or forwarding it, and notify the sender of the error by email reply immediately.
RE: ClassCastException in pcReplaceField
Hey Russell, Thanks for the reply. I don't think I understand what you offered. (By IComparable - I assume you meant simply Comparable) A and B are not comparable objects. They are entirely different object, and that is why it's so strange... I'm posting the stack trace in a few moments.. Russell Collins wrote: It looks like you are trying to add items to a Set. You will get these casting exceptions if your classes do not implement the IComparable interface. If they do implement the interface, then it is another issue. -- View this message in context: http://n2.nabble.com/ClassCastException-in-pcReplaceField-tp4392185p4407472.html Sent from the OpenJPA Users mailing list archive at Nabble.com.
RE: ClassCastException in pcReplaceField
http://n2.nabble.com/file/n4407518/2.pdf 2.pdf That's the stack trace. mypackage, A and B is my stuff. Hope this can be of more use... Thanks, Udi -- View this message in context: http://n2.nabble.com/ClassCastException-in-pcReplaceField-tp4392185p4407518.html Sent from the OpenJPA Users mailing list archive at Nabble.com.
RE: ClassCastException in pcReplaceField
P.S. - I forgot to mention that I'm enhanching at runtime using javaagent. -- View this message in context: http://n2.nabble.com/ClassCastException-in-pcReplaceField-tp4392185p4407523.html Sent from the OpenJPA Users mailing list archive at Nabble.com.
RE: ClassCastException in pcReplaceField
It looks like you are trying to add items to a Set. You will get these casting
exceptions if your classes do not implement the IComparable interface. If they
do implement the interface, then it is another issue.
-Original Message-
From: Rick Curtis [mailto:curti...@gmail.com]
Sent: Thursday, January 14, 2010 5:02 PM
To: users@openjpa.apache.org
Subject: Re: ClassCastException in pcReplaceField
Udi -
You're really going to need to post more information than this for anyone to
figure out what is going on I understand you don't want to post your
application call stack, what about posting a filtered call stack? That might
be a good starting point.
You say you are enhancing your entities at runtime... is that via the
-javaagent or are you using the subclassing support?
--
Thanks,
Rick
On Thu, Jan 14, 2010 at 6:23 AM, Udi saba...@gmail.com wrote:
Hey, first of all, I'm sorry for not pasting the stack - I just can't.
I'm using OpenJPA 1.2.0
I have 2 classes:
class A{
@OneToMany(mappedBy=a)
Set
}
class B{
@ManyToOne
A a;
}
Now, at some point (I can't create a consistent testcase..) I get
ClassCastException: B cannot be cast to A.
The stack (typed, so sorry once again...):
B.pcReplaceField()
StateManagerImpl.replaceField()
StateManagerImpl.storeObjectField()
StateManagerImpl.storeObject()
RelationFieldStrategy.load()
FieldMapping.load()
JDBCStoreManager.load()
I'm enhancing entities at runtime, so I used decompiler to see the
generated
class, and in the problematic line it appears like a cast for a field.
Anyone knows how can it happen (and even more interesting - how to solve
the
problem? :) )
Thanks,
Udi
--
View this message in context:
http://n2.nabble.com/ClassCastException-in-pcReplaceField-tp4392185p4392185.html
Sent from the OpenJPA Users mailing list archive at Nabble.com.
CONFIDENTIALITY NOTICE: The information contained in this electronic mail
(email) transmission (including attachments), is intended by MCLANE ADVANCED
TECHNOLOGIES for the use of the named individual or entity to which it is
addressed and may contain information that is privileged, confidential and/or
protected as a trade secret. It is not intended for transmission to, or receipt
by, any individual or entity other than the named addressee(s). If you have
received this email in error, please delete it (including attachments) and any
copies thereof without printing, copying or forwarding it, and notify the
sender of the error by email reply immediately.
Re: ClassCastException in pcReplaceField
Udi -
You're really going to need to post more information than this for anyone to
figure out what is going on I understand you don't want to post your
application call stack, what about posting a filtered call stack? That might
be a good starting point.
You say you are enhancing your entities at runtime... is that via the
-javaagent or are you using the subclassing support?
--
Thanks,
Rick
On Thu, Jan 14, 2010 at 6:23 AM, Udi saba...@gmail.com wrote:
Hey, first of all, I'm sorry for not pasting the stack - I just can't.
I'm using OpenJPA 1.2.0
I have 2 classes:
class A{
@OneToMany(mappedBy=a)
Set
}
class B{
@ManyToOne
A a;
}
Now, at some point (I can't create a consistent testcase..) I get
ClassCastException: B cannot be cast to A.
The stack (typed, so sorry once again...):
B.pcReplaceField()
StateManagerImpl.replaceField()
StateManagerImpl.storeObjectField()
StateManagerImpl.storeObject()
RelationFieldStrategy.load()
FieldMapping.load()
JDBCStoreManager.load()
I'm enhancing entities at runtime, so I used decompiler to see the
generated
class, and in the problematic line it appears like a cast for a field.
Anyone knows how can it happen (and even more interesting - how to solve
the
problem? :) )
Thanks,
Udi
--
View this message in context:
http://n2.nabble.com/ClassCastException-in-pcReplaceField-tp4392185p4392185.html
Sent from the OpenJPA Users mailing list archive at Nabble.com.
