EJB 1.1 BMP inheritance

Hi,
I have a problem on Weblogic when using Ejb inheritance (with BMP in that
case). The problem seems to come from the fact that the container do not
recognize EJB inheritance. When storing (ejbStore), the container calls
ejbStore on the child ejb with the proper data and then calls the ejbStore
on a parent ejb (where does it come from ?) with all data null except ID set
with the child's ID.
My view is that the inheritance should be declared in deployment descriptors
but I cannot find how ?
Regards
Jacques

I get many erros. Mainly the ejb method not found. This was not happening in OC4J 0.9.0.0.2. Assuming we are not making any code changes, I assuem all I need to do is copy the ear file in OC4J 10g and it should work but it does not. I am using CMP. Has anyone taken an old ear file from prior version and moved to new OC4J server with success. Will like to hear any experience. Thanks.

Similar Messages

Ejb ql query language inheritance Select From

Hi,
I am using TopLink MySQL ejb 3.0 persistence API.
My question is:
How can I write a query that would find only a subclass.?
I hope this shows what I want.
@Entity
class Related{
Parent parent;
@Entity (inheritance=InheritanceType.JOINED)
class Parent{
String address;
@Entity
class Child extends Parent{
String name;
}How can I write this query?? I will write in Java style!
1- Select a from Related a where a.parent (is instanceof (Child))????
2- Select a from Related a where {
if(a.parent instanceof Child){
Child c=(Child) a.parent;
c.name="criteria";
}The idea is selecting those records from Related where it has reference to Child with a specific Criteria.
Thank you.

I figured it out,
It was just a plain query with the specific types I needed.
Thank you.

EJB inheritance

We are in the process of new J2EE development. Our system relies very heavily on inheritance for added flexibility and adaptability. We are inexperienced in EJB, and found that inheritance is not formally supported in the EJB spec.(We are using BMP) We are trying to keep the option of the EJB component layer for purposes of different front-end support (Web/Desktop), but the inheritance flexibility is non-negotiable. Should we rather go client/server, or is there a way in which we can keep the flexibility which inheritance offers and still use EJB?

"zhebincong" <[email protected]> wrote in
news:3da62d9d$[email protected]:
in my ejb tier,i have several session bean,all of them share several
common method,such as "readEmployee().....",etc.
in not order to repeatly code them in every session bean,i want to
wirte a base session bean which have remote,home and iomplementing
class just same as the normal session bean,then other session beans
can inherit from the base bean by all of the remote,home interface and
the ejb implementation,so that the common method can be shared among
multiple session bean. Yes, you can use standard Java inheritance for this.
EJBGen (http://beust.com/cedric/ejbgen) also allows you to extend the
concept of inheritance to elements in the deployment descriptors.
Cedric

Inheritance in EJBs

I am trying to find out if Weblogic supports functionality that TOPLink provides to
represent inheritance.
(http://www.webgain.com/products/toplink/mapping_workbench/demos/
check the "Using Advanced Descriptor Functions", "Inheritance").
I want to have a parent class which has multiple children (i.e. an Account class,
subclasses as Checking, Savings, Loan, etc.). These would all be stored in one database
table. A single 'findAccountsForCustomer' method could return a mixed collection
of the specific child objects.
Is this something available in a current version of Weblogic, or something planned
for the future? Or, is this something that requires a 3rd party mapping tool?

How does this differ from the second option I listed?
Thanks,
Bob
"Nick Minutello" <[email protected]> wrote
in message news:[email protected]...
>
>
You can achieve inheritance using Entity Beans. Its not the simplest ofthings -
but its do-able. (Although I will admit I havent done this for aproduction application).
>
You would create an AccountBean - which is the base-class implementation.Your other
Checking, Savings, Loan Beans inherit from it. (Strictly they dont haveto - this
is only so you have implementation inheritance.)
Then, you would also create an AccountLocal - which is the base-classcomponent interface.
Your other CheckingLocal, SavingsLocal, LoanLocal Interfaces inherit fromit. (this
is so you get polymorphism at the client level)
Your PK classes must be the same all. (though, I forget why at the moment)
You need to create a home for each Bean (this makes sense - you have tohave a factory
that knows what its creating/finding).
You need to list all of them in the DDs. (the CMP mapping duplication is apain)
>
Its all a bit dicky doing it by hand. But if you can get your hands onWSAD4, it
will automate this all for you (Sadly, it only supports EJB1.1.... but youcan see
how it does it)
The thing to remember is that if they are in the same table (I wouldreconsider that
decision) then your findByPrimaryKey method will never be able todistinguish between
them.
The finders are a bit tricky - you need to do the aggregation of thesub-types.
>
-Nick
"Bob Lee" <[email protected]> wrote:
EJB does not support inheritance. You are limited to standard Java's
inheritance capabilities.
If you want to use entity beans, you have the following two options:
1) Have a generic Account entity bean with an account type field (rather
than subclassing).
2) Use Java inheritance, set up an entity bean for each type (Savings,
Checking, etc.) and use a session facade. The findAccountsForCustomer()
method in the session facade will hit each entity bean type and combine
the
results.
I would probably go with the first option. You can use the Strategy
pattern
or something comparable to handle the implementation differences between
the
Account types.
Bob
"Howard Webb" <[email protected]> wrote in message
news:[email protected]...
I am trying to find out if Weblogic supports functionality that TOPLinkprovides to
represent inheritance.
(http://www.webgain.com/products/toplink/mapping_workbench/demos/
check the "Using Advanced Descriptor Functions", "Inheritance").
I want to have a parent class which has multiple children (i.e. an
Account
class,
subclasses as Checking, Savings, Loan, etc.). These would all be
stored
in one database
table. A single 'findAccountsForCustomer' method could return a mixedcollection
of the specific child objects.
Is this something available in a current version of Weblogic, or
something
planned
for the future? Or, is this something that requires a 3rd party
mapping
tool?
>

EJBs and Stored Procedures

Hello!
I want to bind an EJB (probably an BMP entity bean) to the result of a stored procedure.
Can this be done? Are there any examples? thx

You would be after the JDBC CallableStatement interface which is part of JDBC 2.0
Most of the EJB books have a chapter on JDBC which will include it, there are probably examples on the web but I'm afraid I don't know where to find them.

Why BMP

I see the following reasons for using BMP over CMP:
1.Accessing legacy systems and non RDBMS data source.
2.For managing complex relationship.
3.When u r not sure that the CMP code is optimized and would like to use stored procedures for database access with an intent of improving performance.
4.When entity data is found in many databases.
The point # 2 mentioned is no longer valid with the coming up of EJB 2.0 which manages relations.
Any more reasons for using BMP ?
Thanks in advance.

Greetings,
I see the following reasons for using BMP over CMP:
1.Accessing legacy systems and non RDBMS data source.Or simply, any non-RDBMS data source.
2.For managing complex relationship.
3.When u r not sure that the CMP code is optimized and
would like to use stored procedures for database
access with an intent of improving performance.True, though not very portable. In any event, CMP can also make use of stored procedures where out-parameters are not needed. Also, Sun promotes "resource optimization" as a selling point for CMP, ie.: "the vendor may know better than the Bean Provider how to optimize queries to the resources it explicitly supports". :-p Though, in this regard, I still tend to trust my own code better than the vendors. :) Furthermore, CMP alleviates most of the burden of O/R mapping on the Bean Provider by transferring it to the Deployer role. So another question one may find him/herself asking is how much can the Deployer be trusted to effectively manage the mapping? It makes for a possible extension of the "platform gets blamed for coder's lack of skill" syndrome. Another consideration is optimizing bean->resource syncs. In BMP one can use a 'dirty flag' to optimize UPDATEs; in CMP one must rely on the vendor doing so and - with a closed source server, at least - there's little way to know. In such cases, BMP may still the preferred way to go...
4.When entity data is found in many databases.Unless it absolutely must be mapped into a single bean, (EJB 2.0) CMP/CMR can support this too - albeit, not very "efficiently". ':)
The point # 2 mentioned is no longer valid with the
coming up of EJB 2.0 which manages relations.Mostly. EJB 2.0 (CMR) manages relationships between beans, not between the actual entities which still maps 1:1 to the beans. We can say that by extension CMR also manages relationships between the entities. However, the spec only partially provides for CMR-level reflection of resource level handling of foreign keys - IGNORE and CASCADE ON DELETE. (Of course, I should remember my own arguments in support of '1' above.and point out that Entity Beans are not strictly for RDBMSes where such handling originated and is most common... :) If other handling is needed (eg. NULL ON DELETE) then BMP and/or business-level logic must be used.
Any more reasons for using BMP ?How about reuse and portability beyond EJB? In BMP one can (should) use a DAO to sync with the resource. A well written DAO, in conjunction with a Business Delegate, can be easily used in scenarios where an EJB container is either not available or not practical. ;)
Thanks in advance.Regards,
Tony "Vee Schade" Cook

JSF problem

Hi
I have problems when deploying enterprise applications to Sun Java System Application Server 9 that contain JSF pages. The scenario is the following:
I developed an enterprise application using Oracle JDeveloper 10.1.3. My EAR archive contains an EJB module (with BMP Entity Beans according to 2.1 spec) and a WAR module (using JSF 1.1). The app works fine in this IDE.
I've tried to migrate the EAR to Sun Java System Application Server 9. When I upload the EAR to this server, it indicates that deploying is successful, according to the server log. But when I try to access the application through the web browser, an exception is thrown:
HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: jsp.error.beans.property.conversion
Seems like if JSF pages are not compiled correctly when they're contained in an enterprise application.
If I only deploy the WAR, I can access the application, I mean, the index.jsp page is compiled and shown in the web browser. However, the app still doesn't work, because it needs the EJB module. That's why I need to deploy the entire enterprise application as an EAR.
Seems like if Sun Java System Application Server 9 has problems when a deployed EAR contains JSF pages.
I don't know if this is a bug or I'm missing any descriptor or something like that. Hope you can help me please.

Hi, I experimented the same problem. Do you find some solution?
Thanks in advance.

Please help - Toplink on Websphere5.1

Hi,
I am newbie on Toplink and I am trying to use toplink to run on a sample table with EJB 2.0 CMP and Session Facade. I created a project.xml and toplink-ejb-jar.xml(renamed the session.xml for Websphere) using toplink workbench and placed in the META-INF folder . Build the jar and made .ear with .war file to access from web and deployed on to Websphere5.1.1 . Deployment went fine.
When I try to create a record from webpage, looks like it is trying to insert the record into the database with entity bean name as table and throwing the error as " table or view does not exist ". It is understood that it is not going through the Toplink mapping in WebSphere.
In Websphere, I have put the toplink.jar in classpath.
Is there anything missing in configuration in websphere or in jar or in toplink?
Not sure how does Websphere knows it needs to go through the Toplink and Toplink generated xml files?
Appreciate your help. I am not able to find any help on the documentation on this.
Thanks
Sreeni

TopLink does not support EJB 2.0 CMP in Websphere 5.1.
Either make use of TopLink's POJO persistence, TopLink's EJB 2.0 BMP support, or investigate TopLink's EJB 3.0 JPA support.
TopLink 10.1.3 supports EJB 2.0 CMP in Oracle Application Server 10.1.3, and WebLogic 8.
TopLink supports POJO persistence in any application server, or Java environment.

Commit not committing

All of the demo EJBs that use BMP won't commit their chainges. Even the transactional beans that use a UserTransaction actually never get commited to the database.
What causes this? I not the examples but the database is causing this behavior to any BMP EJB, the CMP beans work as they should.
any help would be greatly appreciated

Hi,
This might be due to STATUS_INITIALIZED status. After setting the attributes values from your code are you setting other values also from front end ?
If you are not setting any other values, your row status will remain STATUS_INITIALIZED and thus it will not commit the data to DB.
--Sushant

Bean passivation not completed

Environment: WLS 6.1 SP2 on NT
Hi,
I am loading 50 entities (EJB 2.0 BMP) and playing with WLS configuration
to force the container to passivate them.
I set max-beans-in-cache to 100, idle-timeout-seconds to 10 seconds
and concurrency-strategy to Database.
In addtion, I set the passivation-strategy to transaction to make sure
the container will passivate the bean after every transaction.
I ran my test to list the details of my 50 objects. 50 local entities
are indeed created, but none are passivated.
I would have expected the container to passivate them after 10 seconds
given my idle-timeout-seconds value. My passivation-strategy being set
to transaction, I would have expected the container to passivate them
straight away anyway.
If I change max-beans-in-cache to 30, the container passivates 20 entities
(activation count 50, passivation count 20, idle beans count 20, beans in
use count 30)
If I run it again the values change as expected to
activation count 70 (50+20), passivation count 40 (20+20), idle beans count
20, beans in use count 30.
My questions are:
Is idle-timeout-seconds working ?
Is passivation-strategy working ?
Is the console displaying the right information?
Could someone tell me what is the best practice for passivation policy?
It is not normal that my 50 entities will sit there for the whole day even
if there are not used.
They should be passivated shouldn't they?
Cheers
Arnaud

Arnaud wrote:
Environment: WLS 6.1 SP2 on NT
Hi,
I am loading 50 entities (EJB 2.0 BMP) and playing with WLS configuration
to force the container to passivate them.
I set max-beans-in-cache to 100, idle-timeout-seconds to 10 seconds
and concurrency-strategy to Database.
In addtion, I set the passivation-strategy to transaction to make sure
the container will passivate the bean after every transaction.
Passivation-strategy was deprecated in 6.0. It doesn't do anything in
6.0 or later. Actually it never really worked correctly even in 5.1.
idle-timeout-seconds is not used for entity bean passivation. That
parameter is only used for session beans.
I ran my test to list the details of my 50 objects. 50 local entities
are indeed created, but none are passivated.
I would have expected the container to passivate them after 10 seconds
given my idle-timeout-seconds value. My passivation-strategy being set
to transaction, I would have expected the container to passivate them
straight away anyway.
If I change max-beans-in-cache to 30, the container passivates 20 entities
(activation count 50, passivation count 20, idle beans count 20, beans in
use count 30)Right
If I run it again the values change as expected to
activation count 70 (50+20), passivation count 40 (20+20), idle beans count
20, beans in use count 30.
My questions are:
Is idle-timeout-seconds working ?
Is passivation-strategy working ?See above
Is the console displaying the right information?
Could someone tell me what is the best practice for passivation policy?
It is not normal that my 50 entities will sit there for the whole day even
if there are not used.
They should be passivated shouldn't they?
It depends on your usage. The better solution is in 7.0 where you can
configure application caches that will hold many different types of
EJBs. They're better able to handle mixed EJB loads.
-- Rob
Cheers
Arnaud

Point Database tutorial but using Derby Database in NetBeans IDE

Hi
I am getting an error when I am trying to run the EJB Entity beans BMP example "savingsaccount" in the examples folder of j2eetutorials .
I have using NEtBeans IDE + Sun APP server and the following the tutorial Netbeans + J2ee tutorials...
THe problem is the tutorial talks about a "pointdatabase" 8.1 verson and the Sun App Server I have is 8.2 which has "Derby Database".
However I made the necessary changes in the code. Siill the error is someting like this :
"ar 27, 2006 3:40:57 AM com.sun.corba.ee.spi.logging.LogWrapperBase doLog
INFO: "IOP00710299: (INTERNAL) Successfully created IIOP listener on the specified host/port: all interfaces/1366"
Exception is caught: RemoteException occurred in server thread; nested exception is:
java.rmi.RemoteException: ejbCreate: Invalid argument: parameter index 1 is out of range.
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
java.rmi.RemoteException: ejbCreate: Invalid argument: parameter index 1 is out of range.
at com.sun.corba.ee.impl.javax.rmi.CORBA.Util.mapSystemException(Util.java:161)
at javax.rmi.CORBA.Util.mapSystemException(Util.java:67)
at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.invoke(StubInvocationHandlerImpl.java:142)
at com.sun.corba.ee.impl.presentation.rmi.bcel.BCELStubBase.invoke(Unknown Source)
at bank._SavingsAccountRemoteHome_DynamicStub.create(_SavingsAccountRemoteHome_DynamicStub.java)
at savingsaccountclient.Main.main(Main.java:64)
Caused by: java.rmi.RemoteException: ejbCreate: Invalid argument: parameter index 1 is out of range.
....and more...
So I am not sure whether this is some fault of the application or the database access errior...?
Someone who tried this let me know plz...
thanks
deepesh

Microsoft SQL Driver 2005 JDBC Driver is not the Derby driver.
You need the correct JDBC driver for the database you are using, you can't simply grab the first one you find.

Basic JAR Question

Hello,
I hate to ask such a simple question, but I'd like to get confirmation from people who know.
It is possible to package non-EJBs into a deployed JAR containing EJBs, isn't it? I have heard that you cannot mix a non-EJB class into a JAR that contains EJBs, but my interpretation of the literature I've found about packaging EJBs seems to indicate otherwise.
Basically, it looks like you would want to (or need to in some cases) package any class that an EJB depends upon through inheritance or through another association (e.g. a custom user Exception class that and EJB might throw) into the same JAR file.
Please reply and set me straight on this. Thanks in advance.
Jeff

1. You can include any classes in your EJB jar file, and it is widely used. You can also include other files (e.g. properties) and access them through the class loader (as resources).
2. If you use some libraries, you may reference them with Class-Path: element in your manifest file. It is not necessary to unpack the library and include its classes in your jar file. (About "Class-Path" -- look page about manifest in the java tutorial (in the JAR files trail)).
3. Your JAR can contain no classes, just a deployment descriptor, if your classes are somewhere and you have referenced them with "Class-Path". ;)

Finders in the deployment tool

Hi!
I'm trying to figure out how to write custom finders in the deployment tool.
But I've run into two problems:
1. Can I define my own PrimaryKey class that I use to identify the bean and
how do I configure it in the deployment tool?
- e.g. findByPrimaryKey(CustomPK pk)
- Do I need to configure anyhing in the LightWeightCMP tab in the
deployment tool or is it enough that I give the PrimaryKey class name in the
General tab?
2. How do I configure the findAll method in the deployment tool?
- Is it sufficient that I provide the following information:
- Name: findAllSQL
- Type: java.lang.String
- Value: SELECT C_ID FROM TBL_PARTNER
Thanks in advance for any help I can get!

the tab is for the user to fill in the entries of all the EJBs referenced by the module that is selected in the left side tree.
thus, when you select the client jar, it will show you the EJBs that the client references (as per the deployment descriptor). Likewise for EJBs.
for simple bmp example, the ejb-jar.xml file does not contain any entries of the type <ejb-ref> where as, the application-client.xml (DD for the client) does.
the same logic applies to cmpcustomer example.
hope this helps.

Application server architecture 2

Hello guys,
I have few questions about application server architecture�
I already was asking similar question (http://forum.java.sun.com/thread.jspa?threadID=654898) and got few replies which were looking for me quite ok, but after reading more docs I doubt that suggested approach is right.
So, I have a task to build a server application which will do the following: Clients (special java clients) will connect to it and send some data for further processing on server side. Chunks of data will be relatively small but they will take a lot of time for processing � up to one or two days.
Also server will run some sort of �database� where all clients� working data will be stored. So, in case a client loses its data he/she is always able to download it from the server.
For me it was seeming like server will consist of the following components:
1. �Reception�. This part will be responsible for all client-communication procedures.
2. �Data storage�. This part will simply store all clients� data and provide some API interface for clients through �reception� to manage it (add/get/delete and so on).
3. �Processor�. Some sort of dummy-sophisticated module. It will take some input data from �data storage� when it receives order for this and process it. �Processor� will have two states: �busy� which means �processor� processing some data and �available� which means �processor� ready to process new data.
4. �Manager�. This part will always check �data storage� for new data and �processor� for availability. When �processor� and new data are available �manager� will make an order for �processor� to take new data from �data storage� and process it.
I got few suggestions:
1. Make �Reception� stateless session bean. I agree with it. It is quite reasonable.
2. Make �Data storage� as a session bean that will use entity beans or hibernate to work with persistent data. It is also seems quite reasonable and as it was suggested I would like to implement my own data access mechanisms instead of using those which provided by J2EE server.
3. !!! �Processor�. Suggestion was the following: �Use a message driven bean. Make Reception to enqueue a message when new data is available for processing. Processor will process the data and store the resut in database using Data Storage session bean.� It is quite reasonable, except one little thing: I read that Message Driven Beans are not designed for long time processing. Moreover, for example in my JBoss server, Message Driven Beans have attribute KeepAliveMillis=30000. For me it seems that after 30 second my message driven bean will be killed by server and now I doubt: is message driven bean a good solution for implementation long time running processor?
Now I am thinking that �processor� component should run as an additional application outside of J2EE server and from time to time (when data is finally processed and �processor� available again) send messages to my j2ee server.
So, whole picture will look like this (please have a look on the picture: http://www.flickr.com/photos/77716401@N00/35565234/ ):
1. j2ee server always on and ready to create �reception� session stateless EJB to serve remote clients. At the beginning it thinks that �processor� offline and doesn�t attempt to interact with �processor� in any way.
2. When clients appear to interact with server they simply send or receive package of data without complex interaction. �Reception� simply receives data from clients, pass it to �data mapper� component and tells to �manager� that new data available for �processor� to process. �Data mapper� component stores received data in �database�.
At this point j2ee server does two simple things:
- Collecting information for further processing from remote users
- Returning backups of received information to its owners.
3. �Processor�. �Processor� talks with my j2ee application via �Manager� stateful EJB. When �processor� runs first thing it does it asks �manager� for data to process. If there is new no data to process, �processor� does nothing but �manager� remembers that �processor� is ready to work. If there is data to process �manager� passes data to �processor� and remembers that �processor� is busy.
4. When �processor� finishes processing it does the following:
a. Returns data to �manager�. �Manager� passes processed data to �Data Mapper�. �Data Mapper� stores processed data in database.
b. Asks �manager� for new data to process if there is new data to process, �processor� does nothing but �manager� remembers that �processor� is ready to work. If there is data to process �manager� passes data to �processor� and remembers that �processor� is busy.
5. When client submits new data �reception� tells to �manager� that new data available and it �processor� state is �ready for work� �manager� sends order to process to processor.
And so on. Now for me it seems quite reasonable architecture.
But, since I am very new in j2ee technologies I ask few questions:
1. Is my approach right at total?
2. Is it ok that I would like to make �Reception� stateless EJB, �Data Maper� BMP EJB and �manager� stateful EJB?
3. I know that JMX is a basic concept of J2EE, so I would like to register my database as a resource in my J2EE server. Is it right?
4. I need some sort of component which runs all the time from time server started till it is off. If there is anything like this?
Please, give me some advises and tips!
Thank you in advance!

1. Navigating in SAP systems
--Logon and structure of the user interface
--Accessing functions in the system
--Personalization options
No, this is really nothing more than an introduction for people that have never seen a SAPgui screen before. Most ABAPers can skip right over this course. If you understand the NetWeaver architechure, then I would suggest to start withe BC400.
Regards,
Rich Heilman

EJBDeployer tool and std_ejb_basic_beanManaged

I am using the std_ejb_basic_beanManaged.jar file in the EJB Deployer tool and I can see the bean. This file is part of the examples that come with Weblogic. This EJB contains a BMP bean (bean managed persistent). I click on the + sign to expand the items but I cannot see the item for persistent. I read that there is an item there called persistent and from there I can choose the data store etc.
Can anyone help me with this? ANy help would be greatly appreciated.
thanks,

Please ignore my earlier message. thanks.

EJB 1.1 BMP inheritance

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