RE: Invoking EJB from Action classes
I assume you are accessing the beans through JNDI. I also assume you are using IntitialContext ctx = new InitialContext(); -to generate your initial context object. You May create a jndi.properties file that contains the following: java.naming.factory.initial=name-of-initialContextfactory-implementaion.cla ss java.naming.provider.url=url to host of JNDI service ( probably also your EJB server ) java.naming.security.principal=username to be assigned to this client ...your action class ) java.naming.security.credentials=password to be assigned as credentials for the above username ) Place that jndi.properties file in the classpath of the war file. executing ejb-client code ) If you prefer, you can code the creation of a Hashtable and provide it with those same name value pairs, then get your InitialContext thusly: IntialContext ctx = new InitialContext(myHashtableFullOfNameValuePairs); Refer to your application server's documentation to determine the classname of your vendors' InitialContextFactory. HTH Owen Taylor of The New Customware Company http://www.customware.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Monday, May 21, 2001 12:03 PM To: [EMAIL PROTECTED] Subject: Invoking EJB from Action classes Hi all, I have developed the web front end using Struts framework. When i was trying to deploy the application on Websphere 3.5.2 i am facing problems. From the Action class i am not able to invoke the session bean or entity bean. When the session and entity beans were deployed on the websphere Access permissions were applied on it. Because of these permissions i think i am not able to invoke the beans from my Action objects. How can i invoke the EJB's from Action classes? Thanks in advance. Cheers Rafee ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.Kindlesystems.com **
Re: Invoking EJB from Action classes
- Original Message - From: "Roger Kjensrud" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Monday, January 15, 2001 5:15 PM Subject: RE: Invoking EJB from Action classes Jannik, thanks for your input. The concept of the EJB session manager returning references to other EJBs is interesting. This EJB must be a stateful EJB with one instance per session, correct? Not having the lookup and create logic in the Action class means that this code does not have to be duplicated in a non-HTTP environment where the Action classes probably don't exist. You just have to lookup the session manager, and it will return references for you. Yes, the SessionManager is a stateful EJB. I don't fully understand the JNDI concept with this approach. From your Action class you tell the session manager to return a specific EJB reference, so you have to give it a JNDI name, correct? If this is true, where is the name stored? Hard coded? Config file? We've implemented the home-interface lookup for the EJB SessionManager in the user object (will probably move this to a seperate clientside session manager class later to keep things cleaner). When the user object is bound to the HTTP-session the SessionManager EJB is looked up and a remote interface is stored in the user object. The SessionManager EJB can then be used to get remote interfaces references of other EJB's. The JNDI name of the SessionManager EJB is retrieved from a CORBA-server that keeps all the system specific properties, such as JNDI-name spaces. The properties of read by the CORBA-server is kept in a .properties file. Hope this cleared thing up a bit..:) /jannik Thanks, Roger -Original Message- From: Jannik Nrgaard Steen [mailto:[EMAIL PROTECTED]] Sent: Saturday, January 13, 2001 3:09 AM To: [EMAIL PROTECTED] Subject: Re: Invoking EJB from Action classes Hi, we are storing references to our EJB in the HTTP-session context and it works just fine. We have created an EJB that acts as a session manager. This manager can supply clients with all EJB references to other EJB's one might need during a HTTP-session. On the client side we have a class (to represent a user) that implements the HttpBindingListener interface. When this class is bound to the HTTP-session a reference to the session manager is placed in the HTTP-session and we are ready to go. Once a EJB reference (remote interface) is returned by the session manager it is stored in the HTTP-session by one of our action classes. When the HTTP-session is invalidated remove() is called on all EJB references stored in the HTTP-session. The last to be removed is the session manager so it will have a chance to end transactions. In question of the JNDI lookup, we use a CORBA server (we call it a preferences manager) to supply all clients with the JNDI name space for the EJB's. Cheers, Jannik Nrgaard Steen Software developer Digital Zone International A/S - Original Message - From: "Roger Kjensrud" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 12, 2001 9:50 PM Subject: Invoking EJB from Action classes Hello, I've searched archive about calling EJBs from the Action classes and how to store the EJB reference, and there did not seem to be consensus of how to do this. Since the Action class needs to be coded thread-safe, and you would like to keep the EJB reference, at least for stateful session EJBs, it won't work to use an instance variable to store the reference. What about storing the reference in the session? So, in the perform() method of the Action class you will check to see if the session contains the reference, and if not you will call a method, could be static, that returns the ejbhome reference. This reference can be stored on the session or you can call the create() method on the ejbhome to get a reference to the ejb and store this to the session. I would also consider creating a custom mapping where I would specify the EJB JNDI lookup name in the struts-config.xml file for this particular Action class avoiding hardcoding. Feedback on this approach is appreciated, thanks, Roger Kjensrud
RE: Invoking EJB from Action classes
Jannik, thanks for your input. The concept of the EJB session manager returning references to other EJBs is interesting. This EJB must be a stateful EJB with one instance per session, correct? Not having the lookup and create logic in the Action class means that this code does not have to be duplicated in a non-HTTP environment where the Action classes probably don't exist. You just have to lookup the session manager, and it will return references for you. I don't fully understand the JNDI concept with this approach. From your Action class you tell the session manager to return a specific EJB reference, so you have to give it a JNDI name, correct? If this is true, where is the name stored? Hard coded? Config file? Thanks, Roger -Original Message- From: Jannik Nrgaard Steen [mailto:[EMAIL PROTECTED]] Sent: Saturday, January 13, 2001 3:09 AM To: [EMAIL PROTECTED] Subject: Re: Invoking EJB from Action classes Hi, we are storing references to our EJB in the HTTP-session context and it works just fine. We have created an EJB that acts as a session manager. This manager can supply clients with all EJB references to other EJB's one might need during a HTTP-session. On the client side we have a class (to represent a user) that implements the HttpBindingListener interface. When this class is bound to the HTTP-session a reference to the session manager is placed in the HTTP-session and we are ready to go. Once a EJB reference (remote interface) is returned by the session manager it is stored in the HTTP-session by one of our action classes. When the HTTP-session is invalidated remove() is called on all EJB references stored in the HTTP-session. The last to be removed is the session manager so it will have a chance to end transactions. In question of the JNDI lookup, we use a CORBA server (we call it a preferences manager) to supply all clients with the JNDI name space for the EJB's. Cheers, Jannik Nrgaard Steen Software developer Digital Zone International A/S - Original Message - From: "Roger Kjensrud" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 12, 2001 9:50 PM Subject: Invoking EJB from Action classes Hello, I've searched archive about calling EJBs from the Action classes and how to store the EJB reference, and there did not seem to be consensus of how to do this. Since the Action class needs to be coded thread-safe, and you would like to keep the EJB reference, at least for stateful session EJBs, it won't work to use an instance variable to store the reference. What about storing the reference in the session? So, in the perform() method of the Action class you will check to see if the session contains the reference, and if not you will call a method, could be static, that returns the ejbhome reference. This reference can be stored on the session or you can call the create() method on the ejbhome to get a reference to the ejb and store this to the session. I would also consider creating a custom mapping where I would specify the EJB JNDI lookup name in the struts-config.xml file for this particular Action class avoiding hardcoding. Feedback on this approach is appreciated, thanks, Roger Kjensrud
Re: Invoking EJB from Action classes
Roger Kjensrud wrote: Jannik, thanks for your input. The concept of the EJB session manager returning references to other EJBs is interesting. This EJB must be a stateful EJB with one instance per session, correct? Not having the lookup and create logic in the Action class means that this code does not have to be duplicated in a non-HTTP environment where the Action classes probably don't exist. You just have to lookup the session manager, and it will return references for you. I don't fully understand the JNDI concept with this approach. From your Action class you tell the session manager to return a specific EJB reference, so you have to give it a JNDI name, correct? If this is true, where is the name stored? Hard coded? Config file? The web application deployment descriptor includes several elements (such as ejb-ref) for precisely this purpose. The details of how they are used is defined in the J2EE specification, which you can grab via http://java.sun.com/j2ee. Thanks, Roger Craig McClanahan -Original Message- From: Jannik Nrgaard Steen [mailto:[EMAIL PROTECTED]] Sent: Saturday, January 13, 2001 3:09 AM To: [EMAIL PROTECTED] Subject: Re: Invoking EJB from Action classes Hi, we are storing references to our EJB in the HTTP-session context and it works just fine. We have created an EJB that acts as a session manager. This manager can supply clients with all EJB references to other EJB's one might need during a HTTP-session. On the client side we have a class (to represent a user) that implements the HttpBindingListener interface. When this class is bound to the HTTP-session a reference to the session manager is placed in the HTTP-session and we are ready to go. Once a EJB reference (remote interface) is returned by the session manager it is stored in the HTTP-session by one of our action classes. When the HTTP-session is invalidated remove() is called on all EJB references stored in the HTTP-session. The last to be removed is the session manager so it will have a chance to end transactions. In question of the JNDI lookup, we use a CORBA server (we call it a preferences manager) to supply all clients with the JNDI name space for the EJB's. Cheers, Jannik Nrgaard Steen Software developer Digital Zone International A/S - Original Message - From: "Roger Kjensrud" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 12, 2001 9:50 PM Subject: Invoking EJB from Action classes Hello, I've searched archive about calling EJBs from the Action classes and how to store the EJB reference, and there did not seem to be consensus of how to do this. Since the Action class needs to be coded thread-safe, and you would like to keep the EJB reference, at least for stateful session EJBs, it won't work to use an instance variable to store the reference. What about storing the reference in the session? So, in the perform() method of the Action class you will check to see if the session contains the reference, and if not you will call a method, could be static, that returns the ejbhome reference. This reference can be stored on the session or you can call the create() method on the ejbhome to get a reference to the ejb and store this to the session. I would also consider creating a custom mapping where I would specify the EJB JNDI lookup name in the struts-config.xml file for this particular Action class avoiding hardcoding. Feedback on this approach is appreciated, thanks, Roger Kjensrud
Re: Invoking EJB from Action classes
Hi, we are storing references to our EJB in the HTTP-session context and it works just fine. We have created an EJB that acts as a session manager. This manager can supply clients with all EJB references to other EJB's one might need during a HTTP-session. On the client side we have a class (to represent a user) that implements the HttpBindingListener interface. When this class is bound to the HTTP-session a reference to the session manager is placed in the HTTP-session and we are ready to go. Once a EJB reference (remote interface) is returned by the session manager it is stored in the HTTP-session by one of our action classes. When the HTTP-session is invalidated remove() is called on all EJB references stored in the HTTP-session. The last to be removed is the session manager so it will have a chance to end transactions. In question of the JNDI lookup, we use a CORBA server (we call it a preferences manager) to supply all clients with the JNDI name space for the EJB's. Cheers, Jannik Nrgaard Steen Software developer Digital Zone International A/S - Original Message - From: "Roger Kjensrud" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 12, 2001 9:50 PM Subject: Invoking EJB from Action classes Hello, I've searched archive about calling EJBs from the Action classes and how to store the EJB reference, and there did not seem to be consensus of how to do this. Since the Action class needs to be coded thread-safe, and you would like to keep the EJB reference, at least for stateful session EJBs, it won't work to use an instance variable to store the reference. What about storing the reference in the session? So, in the perform() method of the Action class you will check to see if the session contains the reference, and if not you will call a method, could be static, that returns the ejbhome reference. This reference can be stored on the session or you can call the create() method on the ejbhome to get a reference to the ejb and store this to the session. I would also consider creating a custom mapping where I would specify the EJB JNDI lookup name in the struts-config.xml file for this particular Action class avoiding hardcoding. Feedback on this approach is appreciated, thanks, Roger Kjensrud
