I agree with your concerns below. The code in question comes from SPECj2004 (originally SPECj2002 which was only an EJB benchmark) which was developed jointly by IBM, BEA, Oracle, Sybase, Intel, Sun, etc. There was some discussion in the OSG-Java subcommittee over this issue as some vendors interpreted the SPEC as not allowing CMP / CMR overlap. However, the implementations available at the time (already shipping and being used) allowed for the overlap and put the responsibility for using the CMP / CMR correctly. For instance, there was a protracted debate about someone breaking a relationship by setting the CMP field to a different value and breaking the relationship without the container's knowledge. Given the ambiguity in the SPEC we decided to let the current implementations be the defining standard and as a group allowed for the overlap of CMP / CMRs as well as for the manual setting of them. The Sun One AppServer recently published results using this benchmark and executes this code without error. To be consistent with the other implementations we should follow that behaviour.
It might be nice to cache the expected value in the engine and perform a verification step at transaction commit that would throw an exception if a field had been modified unexpectedly. I don't believe any of the Application Servers do that today but I'm not sure. Would you be in favor of blindly following the defacto standard or leave this as an optional feature that provides for advanced protection? Thanks. Matt ----- Original Message ----- From: "Gianny Damour" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, June 14, 2005 7:20 AM Subject: Re: [openejb-dev] Problem setting the PK in an entity bean with a relationship > On 14/06/2005 12:42 PM, Matt Hogstrom wrote: > >>I have a typical bean sequence where there is an Order and a number of Order >>Lines. (1 ... many) The OrderEnt is created from a Session bean >>coincidentally named OrderSes. The OrderEnt then in ejbPostCreate creates >>the appropriate OrderLines. Here is the code from OrderEnt: >> >> public void ejbPostCreate(OrderDataBean odb, boolean deferred) >> throws CreateException { >> >> > <snip> > >>Depending on the situation one of the above orderLineHome.create methods is >>invoked. So far, so good. >> >>In the OrderLineEnt.create method things go a bit wrong. Here is the stack >>trace: >> >>Caused by: javax.ejb.EJBException: cmp-field [orderId] is read-only. >> at >> org.tranql.ejb.ReadOnlyCMPFieldAccessor.set(ReadOnlyCMPFieldAccessor.java:44) >> at org.openejb.entity.cmp.CMPSetter.invokeInstance(CMPSetter.java:74) >> at >> org.openejb.entity.cmp.CMPMethodInterceptor.intercept(CMPMethodInterceptor.java:75) >> >> > Based on this stack-trace, I confirm that the CMP field orderId is > mapped to a foreign key. > >>Here is the ejbCreate method that is failing >> >> public OrderLineEntPK ejbCreate(int id, Integer orderId, String itemId, >> int quantity, BigDecimal totalValue, >> int olineStatus, java.sql.Date shipDate, BigDecimal msrp) >> throws CreateException { >> >> if( debugging ) >> debug.println(3, "ejbCreate of ol_id = " + id + ", o_id = " >> + orderId); >> >> setId(id); >> setOrderId(orderId); <==================== >> This is the line that is failing. >> setItemId(itemId); >> setQuantity(quantity); >> setTotalValue(totalValue.setScale(2, BigDecimal.ROUND_UP)); >> setOlineStatus(olineStatus); >> >> >> >>OrderId is the FK to the Order. >> >> > Fields mapped to foreign key columns are read-only. They are read-only > for the following reason: > Let's assume that: > * we have one existing line item lineItemEntity; > * lineItemEntity is already related to an order orderEntity; > * orderEntity is related to two line items, lineItemEntity (as expected) > and lineItemEntity2; > * we want to relate lineItemEntity to a new order orderEntity2; > * orderEntity2 is related to zero line items; and > * line item defines a CMR field order to set its related order. > > In this specific scenario, if we set the CMR field order of > lineItemEntity to orderEntity2, then: > * orderEntity2 is now related to the line item lineItemEntity; and > * orderEntity is now related to only one line item lineItemEntity2. > > In this same scenario, if we set the CMP field orderId of lineItemEntity > to the primary key of orderEntity2, then I am not sure of what the > result should be. Indeed, it is a CMP field and no specfic semantic is > attached to it. > > To some extent, I am not sure that we should allow developers to update > relationships via a direct update to the underlying foreign key columns. > We could implement a fix to have a CMR semantic for CMP fields mapped to > foreign ley columns; yet it does not sound good. Having said that, I do > not have a strong opinion and I am happy to support such a scenario, if > we need to. > > Also, it is worth to notice that such a potential fix will only be able > to handle CMP having simple primary keys. CMP having compound primary > keys will still have a read-only approach. > >>First question is the deployment right for this scenario? If it is, then I >>think that the container is not acting correctly. This code runs on >>WebLogic, Sun One, WebSphere, etc. >> >> > Do you know if they properly support such scenarii (the CMP field must > have a CMR semantic)? Also, do you know if they do not allow such > scenarii in the case of compound PK CMP? > > Thanks, > Gianny > >>Cheers, >> >>- Matt >> >> >> >> > > >
