Re: What are EJB
thank you - no rush. can wait until next week. r/luba - Original Message - From: "Sam Newman" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, June 18, 2001 4:54 PM Subject: Re: What are EJB > Hmm...I can certainly send you the config files Orcas uses to work with > Tomcat. I'll try and dig them out (off site at the moment - back next week). > One way to communicate with an EJB container without any config problems at > all, is to use RMI.You bind an RMI object at your EJB container's machine, > which will act as a proxy to the EJB (mine is in fact called > CentralServerProxy). Your servlets then act as an RMI client. All you have > to do to get this to work is run tomcat with a security manager (so you'll > need java 2, and you have to uncomment the relevent line out of your > server.xml), start an RMI security manager before retrieving the reference > to the object, and tailor your tomcat.policy file to allow access (I ended > up granting everything full permissions because I couldn't be bothered to do > it properly :-) ). The beauty of this approach is that: > 1.)Tomcat doesn't have to be on the same machine as your EJB container as > the communication is RMI (wouldn't be that secure though). It could even > work over the web (RMI is simply a Java specific layer on Corba). > 2.) You abstract the underlying EJB container. Different containers might > require different configuration's for tomcat and the container itself to get > communication to work. > I can go into more detail if you want (I have the code here). It doesn't > take too long to setup, and you can easily protoype the system without an > EJB container behind your Proxy RMI object - you could equally just use JDBC > to connect to MySql or something. Using servlets as an RMI client is > outlines in the Servlet Programming book, in the odds and ends chapter I > think (left my copy at the office!). > Obviously you could use other communication mechanisms to abstract the > communication - we also use 1024 bit encrypted secure pipes to communicate > over the web between out central EJB server and client processes. > > sam > ----- Original Message - > From: "Luba Powell" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Monday, June 18, 2001 5:31 PM > Subject: Re: What are EJB > > > > You think so? I will give in another chance. > > Can you send to me configurations for Tomcat/EJB? > > > > thank you. > >
Re: What are EJB
Hmm...I can certainly send you the config files Orcas uses to work with Tomcat. I'll try and dig them out (off site at the moment - back next week). One way to communicate with an EJB container without any config problems at all, is to use RMI.You bind an RMI object at your EJB container's machine, which will act as a proxy to the EJB (mine is in fact called CentralServerProxy). Your servlets then act as an RMI client. All you have to do to get this to work is run tomcat with a security manager (so you'll need java 2, and you have to uncomment the relevent line out of your server.xml), start an RMI security manager before retrieving the reference to the object, and tailor your tomcat.policy file to allow access (I ended up granting everything full permissions because I couldn't be bothered to do it properly :-) ). The beauty of this approach is that: 1.)Tomcat doesn't have to be on the same machine as your EJB container as the communication is RMI (wouldn't be that secure though). It could even work over the web (RMI is simply a Java specific layer on Corba). 2.) You abstract the underlying EJB container. Different containers might require different configuration's for tomcat and the container itself to get communication to work. I can go into more detail if you want (I have the code here). It doesn't take too long to setup, and you can easily protoype the system without an EJB container behind your Proxy RMI object - you could equally just use JDBC to connect to MySql or something. Using servlets as an RMI client is outlines in the Servlet Programming book, in the odds and ends chapter I think (left my copy at the office!). Obviously you could use other communication mechanisms to abstract the communication - we also use 1024 bit encrypted secure pipes to communicate over the web between out central EJB server and client processes. sam - Original Message - From: "Luba Powell" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, June 18, 2001 5:31 PM Subject: Re: What are EJB > You think so? I will give in another chance. > Can you send to me configurations for Tomcat/EJB? > > thank you.
Re: What are EJB
You think so? I will give in another chance. Can you send to me configurations for Tomcat/EJB? thank you. - Original Message - From: "Sam Newman" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, June 18, 2001 12:14 PM Subject: Re: What are EJB > Problem is all the containers we've used up till now have had real problems > with bean managed persistance...as a result we had to avoid it. They seem > better now, but its a bit late for us. The single biggest headache I've had > developing/designing EJB's is trying to make the OO centric java (e.g. > encapsulation of data and process) work with the non-OO databases without > sacrificing too many of the advantages of the two (databases speed, Javas > flexibility). > I'm looking forward to the new message beans which are in the new EJB 2.0 > spec. Would of made my current project a whole lot easier... Sending > messages/setting state of beans via JMS could be very cool - if it works :-) > > sam > > - Original Message - > From: "Luba Powell" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Monday, June 18, 2001 4:38 PM > Subject: Re: What are EJB > > > > << but a real mess of a database>> > > > > You are right here. Because of it I stopped using Entity beans all > > together... > > > > > > - Original Message - > > From: "Sam Newman" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Monday, June 18, 2001 9:26 AM > > Subject: Re: What are EJB > > > > > > > The only real similarity between EJB's and normal JavaBeans is that they > > are > > > both based on component models. EJB's provide a java representation of > > some > > > data in a database - e.g. 1 EJB will equal 1 row in the table, 1 EJB > class > > > is tied to one table. XML is used to tie an EJB and its data to a > > database. > > > There is a bit of a problem with this approach, in that a typical OO > > design > > > for such a system can result in a good OO system on the surface, but a > > real > > > mess of a database > > > > > > EJB's need a compliant EJB server, and a database. There are a few free > > > versions around - try JBoss. They work fine with Servlets/Tomcat given > > that > > > they are also part of the j2ee. I personally use Cape Connect (previosly > > > Orcas) with tomcat without too many problems (there are a couple of > class > > > loader issues in some circumstances however). Orcas actually bundles > > Tomcat > > > with it, and they pre-configure it to work with their ejb container. > > > > > > sam > > > - Original Message - > > > From: "Alexandre Bouchard" <[EMAIL PROTECTED]> > > > To: <[EMAIL PROTECTED]> > > > Sent: Sunday, June 17, 2001 6:07 PM > > > Subject: What are EJB > > > > > > > > > > I've got a simple question: What are Enterprise Java Beans. I mean, > > what's > > > > the difference between EJB and the beans I develop with JDK and run > with > > > > Tomcat? > > > > > > > > Thx > > > > > > > > > >
Re: What are EJB
Problem is all the containers we've used up till now have had real problems with bean managed persistance...as a result we had to avoid it. They seem better now, but its a bit late for us. The single biggest headache I've had developing/designing EJB's is trying to make the OO centric java (e.g. encapsulation of data and process) work with the non-OO databases without sacrificing too many of the advantages of the two (databases speed, Javas flexibility). I'm looking forward to the new message beans which are in the new EJB 2.0 spec. Would of made my current project a whole lot easier... Sending messages/setting state of beans via JMS could be very cool - if it works :-) sam - Original Message - From: "Luba Powell" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, June 18, 2001 4:38 PM Subject: Re: What are EJB > << but a real mess of a database>> > > You are right here. Because of it I stopped using Entity beans all > together... > > > - Original Message - > From: "Sam Newman" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Monday, June 18, 2001 9:26 AM > Subject: Re: What are EJB > > > > The only real similarity between EJB's and normal JavaBeans is that they > are > > both based on component models. EJB's provide a java representation of > some > > data in a database - e.g. 1 EJB will equal 1 row in the table, 1 EJB class > > is tied to one table. XML is used to tie an EJB and its data to a > database. > > There is a bit of a problem with this approach, in that a typical OO > design > > for such a system can result in a good OO system on the surface, but a > real > > mess of a database > > > > EJB's need a compliant EJB server, and a database. There are a few free > > versions around - try JBoss. They work fine with Servlets/Tomcat given > that > > they are also part of the j2ee. I personally use Cape Connect (previosly > > Orcas) with tomcat without too many problems (there are a couple of class > > loader issues in some circumstances however). Orcas actually bundles > Tomcat > > with it, and they pre-configure it to work with their ejb container. > > > > sam > > - Original Message - > > From: "Alexandre Bouchard" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Sunday, June 17, 2001 6:07 PM > > Subject: What are EJB > > > > > > > I've got a simple question: What are Enterprise Java Beans. I mean, > what's > > > the difference between EJB and the beans I develop with JDK and run with > > > Tomcat? > > > > > > Thx > > > > > >
Re: What are EJB
<< but a real mess of a database>> You are right here. Because of it I stopped using Entity beans all together... - Original Message - From: "Sam Newman" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, June 18, 2001 9:26 AM Subject: Re: What are EJB > The only real similarity between EJB's and normal JavaBeans is that they are > both based on component models. EJB's provide a java representation of some > data in a database - e.g. 1 EJB will equal 1 row in the table, 1 EJB class > is tied to one table. XML is used to tie an EJB and its data to a database. > There is a bit of a problem with this approach, in that a typical OO design > for such a system can result in a good OO system on the surface, but a real > mess of a database > > EJB's need a compliant EJB server, and a database. There are a few free > versions around - try JBoss. They work fine with Servlets/Tomcat given that > they are also part of the j2ee. I personally use Cape Connect (previosly > Orcas) with tomcat without too many problems (there are a couple of class > loader issues in some circumstances however). Orcas actually bundles Tomcat > with it, and they pre-configure it to work with their ejb container. > > sam > - Original Message - > From: "Alexandre Bouchard" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Sunday, June 17, 2001 6:07 PM > Subject: What are EJB > > > > I've got a simple question: What are Enterprise Java Beans. I mean, what's > > the difference between EJB and the beans I develop with JDK and run with > > Tomcat? > > > > Thx > > >
Re: What are EJB
The only real similarity between EJB's and normal JavaBeans is that they are both based on component models. EJB's provide a java representation of some data in a database - e.g. 1 EJB will equal 1 row in the table, 1 EJB class is tied to one table. XML is used to tie an EJB and its data to a database. There is a bit of a problem with this approach, in that a typical OO design for such a system can result in a good OO system on the surface, but a real mess of a database EJB's need a compliant EJB server, and a database. There are a few free versions around - try JBoss. They work fine with Servlets/Tomcat given that they are also part of the j2ee. I personally use Cape Connect (previosly Orcas) with tomcat without too many problems (there are a couple of class loader issues in some circumstances however). Orcas actually bundles Tomcat with it, and they pre-configure it to work with their ejb container. sam - Original Message - From: "Alexandre Bouchard" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, June 17, 2001 6:07 PM Subject: What are EJB > I've got a simple question: What are Enterprise Java Beans. I mean, what's > the difference between EJB and the beans I develop with JDK and run with > Tomcat? > > Thx >
RE: What are EJB
What do you mean by "include EJBs in Tomcat4" ? It´s possible to use EJBs with tomcat in current verison,to do so you can download Jboss (www.jboss.org) and you have an EJB container... bye -r -Original Message- From: Luba Powell [mailto:[EMAIL PROTECTED]] Sent: Sunday, June 17, 2001 10:08 PM To: [EMAIL PROTECTED] Subject: Re: What are EJB <> Correction. *bean* word (not work) - Original Message - From: "Luba Powell" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, June 17, 2001 1:17 PM Subject: Re: What are EJB > putting Tomcat in your message was smart. this way we won't get in > trouble with our colleagues. > > From were I stand the only thing that EJB and JavaBeans have in > common is the presence of bean work in the name. > > I am sure that you know what is the advantage of JavaBeans since > you wrote some. EJB is normally used in e-commerce applications > that remotely communicate with enterprise databases and maintain > sessions across many machines. Again, from where I stand - they > are perfect for some e-commerce apps, but it is not the greatest fit > of engineering. > > There is a way to include EJBs in Tomcat4. Haven't tried it yet. > > r/luba > > > - Original Message - > From: "Alexandre Bouchard" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Sunday, June 17, 2001 1:07 PM > Subject: What are EJB > > > > I've got a simple question: What are Enterprise Java Beans. I mean, what's > > the difference between EJB and the beans I develop with JDK and run with > > Tomcat? > > > > Thx > > > > >
Re: What are EJB
<> Correction. *bean* word (not work) - Original Message - From: "Luba Powell" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, June 17, 2001 1:17 PM Subject: Re: What are EJB > putting Tomcat in your message was smart. this way we won't get in > trouble with our colleagues. > > From were I stand the only thing that EJB and JavaBeans have in > common is the presence of bean work in the name. > > I am sure that you know what is the advantage of JavaBeans since > you wrote some. EJB is normally used in e-commerce applications > that remotely communicate with enterprise databases and maintain > sessions across many machines. Again, from where I stand - they > are perfect for some e-commerce apps, but it is not the greatest fit > of engineering. > > There is a way to include EJBs in Tomcat4. Haven't tried it yet. > > r/luba > > > - Original Message - > From: "Alexandre Bouchard" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Sunday, June 17, 2001 1:07 PM > Subject: What are EJB > > > > I've got a simple question: What are Enterprise Java Beans. I mean, what's > > the difference between EJB and the beans I develop with JDK and run with > > Tomcat? > > > > Thx > > > > >
Re: What are EJB
putting Tomcat in your message was smart. this way we won't get in trouble with our colleagues. >From were I stand the only thing that EJB and JavaBeans have in common is the presence of bean work in the name. I am sure that you know what is the advantage of JavaBeans since you wrote some. EJB is normally used in e-commerce applications that remotely communicate with enterprise databases and maintain sessions across many machines. Again, from where I stand - they are perfect for some e-commerce apps, but it is not the greatest fit of engineering. There is a way to include EJBs in Tomcat4. Haven't tried it yet. r/luba - Original Message - From: "Alexandre Bouchard" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, June 17, 2001 1:07 PM Subject: What are EJB > I've got a simple question: What are Enterprise Java Beans. I mean, what's > the difference between EJB and the beans I develop with JDK and run with > Tomcat? > > Thx > >
