Offtopic: Architecture Question
We are building a B2B exchange for the semiconductor industry. Theres a intranet version which is going to support 150 users, we are currently in the process of building using JSP/Servlets and JavaBeans, we are using DbConnectionBroker for connectionpooling services and JRUN as the JSP/Servlet platform. Question: The Client wants us to build an internet version of the system, and obviously it has to be much more scalable(probably about 10,000 or more users) than the intranet version. My Question is do we have to re-architect the intranet system and go for an App Server like BEA Weblogic or IBM WebSphere or does/can the Jrun architecture handle this load. This system is not very transaction intensive and does not have the data concurrency problems which most OLTP systems have. Appreciate your inputs Thanks for your time Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". Some relevant FAQs on JSP/Servlets can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
Re: Connection Pool
Hi Thomas,
I have 2 questions,
1. the protected instance in the Singleton class should be static
right? and Im sure thats what you meant.
2. Also shouldn't you make both the get and put methods thread safe.
You've mentioned that only the Put method should be thread safe. Can i
Synchronize on the static instance to make the methods threadsafe
Thanks for your time
Sanjay
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, April 04, 2000 10:53 AM
To: [EMAIL PROTECTED]
Subject: SV: Connection Pool
Hi Sanjay
The best way is to implemets a Singelton (see the GoF book) that uses a
ConnectionPool.
public class ConnectionPoolAsSingelton {
protected ConnectionPoolAsSingelton instance; // Store the
Singelton here
private ConnectionPoolAsSingelton(...) { // yes private
constructor
}
public static ConnectionPoolAsSingelton getInstance() {
if(instance==null)
return new ConnectionPoolAsSingelton();
else
return instance;
}
//Put methods for your connpool here but keep in mind that this
code should bee thread safe.
}
to get an instance of connectionpool just call the static function
ConnectionPoolAsSingelton pool =
ConnectionPoolAsSingelton.getInstance();
This should work fine but if you have any problems pleas email me att
[EMAIL PROTECTED]
/Thomas
-Ursprungligt meddelande-
Från: [EMAIL PROTECTED]
[SMTP:[EMAIL PROTECTED]]
Skickat:den 4 april 2000 15:57
Till: [EMAIL PROTECTED]
Ämne: Connection Pool
I am trying to set up a connection pool for my JSP Project. Now I
know that
there are few ways to implement a connectionpool. My first thought
was to
put in the the servlets init method,But then what do i do for my
other
servlets/JSPs, do i create a connectionpool for every servlet?.
Is there a standard technique for implementing connection pools. I
think
the best solution would be to have it in a common place which all the
JSPs
and servlets can access, something like a global.asa file in ASP.
I would like to hear your thoughts on this.
Thanks for your time
Sanjay
=
==
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Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
<>
===
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
Connection Pool
I am trying to set up a connection pool for my JSP Project. Now I know that there are few ways to implement a connectionpool. My first thought was to put in the the servlets init method,But then what do i do for my other servlets/JSPs, do i create a connectionpool for every servlet?. Is there a standard technique for implementing connection pools. I think the best solution would be to have it in a common place which all the JSPs and servlets can access, something like a global.asa file in ASP. I would like to hear your thoughts on this. Thanks for your time Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". Some relevant FAQs on JSP/Servlets can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
Illegal Operation with JRun and JDBC on Win 95
I have simple JSP page which makes a db connection to an access database using the JDBC-ODBC bridge driver. The page gets the info from one do the tables and displays it as HTML. If I hit the referesh this page on the browser for more than thrice i get an Illegal Operation error from windows 95. Is this because of the JDBC-ODBC bridge. Im using Jrun for my JSP and Apache web server 1.3.x Have anyone experienced this problem, if so can you share your thoughts. Thanks for your time. Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". Some relevant FAQs on JSP/Servlets can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
Controlling Threads in Servlets/JSP
I am writing a servlet/JSP which spawns three java threads and has to wait for the 3 threads to finish processing before sending the results got from the threads to the client browser. Here a gist of what i do --- doGet method create thread1 create thread2 create thread3 start thread1 start thread2 start thread3 wait for all threads to complete. This could be a while loop While(atleast one thread is running) sleep send output back as html. --- I know this can be done in different ways using wait/notify and yield/suspend/resume etc. I would like to hear from you guys about the most efficient way to do it. Appreciate your inputs Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
OFFTOPIC: Data Concurrency & Consistency
Im wondering if there are any tools/libraries/frameworks which allows applications written in Java to easily maintain data concurrency/consistency . Let me give a case where i would need this tooll/library. User 1 selects records 1,2 & 3 from table A User 2 selects records 1,3 & 4 from table A User 2 updates record 1 with a different set of values. Now User 1 tries to update record 1 with his set of values. But user 1s update would fail because he won't be able to find the record he retrieved(i.e. record 1) as it would have been already changed by user 2. To avoid this the app would have include the original values that user 1 retrieved from the database initially. If the app does this then there wont be a match in the database for this update statement and the app can flash a message to user 1 saying the record has already been updated/deleted by another user. Do any of you know of a tool/library/bean which can give the same type of functionality. Ideal case would be i would just have to declare to the bean to use Key and Modifiable columns or Just Key columns or Key and updateable columns in the where clause and it would generate the update/insert/delete statement accordingly. Appreciate your inputs Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Re: Members of SessionBeans in JSP
Craig, I really appreciate your inputs. I fully agree with your comments as to not storing resultsets in session beans. I was just trying to understand how sessionbeans are made persistent,Infact I was planning to use some other Java Object similar to the CachedRowSet from JavaSoft and store that in my session bean. I am happy that thats the recommended approach. One more question: What would i have to do in order to destroy a session bean in the middle of a session. That sounds like an Oxymoron doesn't it. Thanks for your time Sanjay -Original Message- From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 05, 2000 3:57 PM To: Radhakrishnan, Sanjay (c) Cc: [EMAIL PROTECTED] Subject: Re: Members of SessionBeans in JSP "Radhakrishnan, Sanjay (c)" wrote: > Accoring to my understanding Data Members of SessionBeans in JSP should be > serializable. So ResultSet and Connection Objects cannot be Members of > Session Beans. Am i right in Saying that? > Per the 2.2 servlet spec, the objects you store in a session bean must be serializable only if your application is marked distributable (i.e. it can run in more than one JVM at the same time). Otherwise, it is optional. > > Yet when i include resultset objects as members of session beans, the > resultset(inside a sessionbean) created by one page are accessible thru > another page(Both pages make use of the Bean tag). I am assuming that > Jrun(which i use) employs serialization to achieve this. > Serialization is not required for this -- instead, the session data objects are shared between all the JSP pages and servlets in the application. It is the same ResultSet instance, so no copying is required. > > How is that possible if Resultsets are not serializable. > > Appreciate your inputs > There is a different reason, though, that I would recommend against storing ResultSets in user sessions even though it works. It has to to with the scalability of your application. Storing the result set in the session implies that it is going to remain there across requests from the user (otherwise you might as well store it as a request attribute). To be usable in a subsequent request, the ResultSet must remain open, which implies that the corresponding Statement that created it must remain open, which implies that the database connection which created this Statement must remain allocated to this user. (You can get away with sharing a connection across multiple users in a read only environment, but transactional COMMIT and ROLLBACK commands will cause interference if you are updating things.) This means that you need an available connection for each simultaneous user, even if that user just took off for lunch. The recommended approach to scalability is to use a connection pool, and (within a single request), always give back the connection you were using before you return the result page to the user. The implication for this discussion is that you should copy the result data you need to keep into some Java object of your own (maybe a Vector full of beans that contain a bean per row or something like that), so that you can close the result set (and the associated statement, and release the connection) before returning the page. Using this approach, the number of database connections you have only limits the number of simultaneous requests you can handle, instead of the number of users currently logged on to your applicaiton. Depending on how active the users are, these two numbers can be *substantially* different. > > Sanjay > Craig McClanahan === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Members of SessionBeans in JSP
Accoring to my understanding Data Members of SessionBeans in JSP should be serializable. So ResultSet and Connection Objects cannot be Members of Session Beans. Am i right in Saying that? Yet when i include resultset objects as members of session beans, the resultset(inside a sessionbean) created by one page are accessible thru another page(Both pages make use of the Bean tag). I am assuming that Jrun(which i use) employs serialization to achieve this. How is that possible if Resultsets are not serializable. Appreciate your inputs Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Re: JSP developer tool
I may be wrong, but Forte for Java does not have a HTML Page builder. It has a JSP and Servlet Builder Sanjay -Original Message- From: Walter Bauer [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 05, 2000 9:57 AM To: [EMAIL PROTECTED] Subject: Re: JSP developer tool Look at Forte for Java (www.netbeans.com) - a complete development environment with JSP and Servlet support (check for the internet moduls as well). Best regards, Walter Michael Parcewski wrote: > Visual Slickedit one of the best tools I've used for JavaServelets and JSP, > check it out at www.slickedit.com, it has strong HTML and Java Syntax > Support and is available both for windows and linux. > > - Original Message - > From: Høye Pål <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Wednesday, December 29, 1999 7:10 AM > Subject: JSP developer tool > > > I have programmed XML using JSP for some time now using TextPad. I wonder > if > > there is anybody who has a recommendation for a good JSP developing tool. > I > > know Oracle's JDeveloper and IBM's WebSphere Studio has JSP support, but I > > am not happy with them. They give help on the HTML syntax and some (not > all) > > of the JSP syntax, but the do not support the Java code inside the JSP > > itself. > > > > I will be happy for recommendations. > > > > > > Pål Høye > > Systemutvikler > > Merkantildata Applikasjon AS > > > > > === > > To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff > JSP-INTEREST". > > FAQs on JSP can be found at: > > http://java.sun.com/products/jsp/faq.html > > http://www.esperanto.org.nz/jsp/jspfaq.html > > === > To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". > FAQs on JSP can be found at: > http://java.sun.com/products/jsp/faq.html > http://www.esperanto.org.nz/jsp/jspfaq.html === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Off Topic: JConnect and Updatable result sets
We are using a Sybase database in our application(which uses JSPs). JConnect is the JDBC driver from Sybase. Jconnect 5.2 claims that it is compliant with JDBC 2.0, but does not fully implement scrollable resultsets and even the Updatable resulsets doesn't work well either. In such a scenario, how should one implement scrollable and updatable result sets. Do we have to build our own library, may be build a vector object/class which resembles the resultset and do all data manipulation inside the vector object and let the Vector generate update statements or Are there any off the shelf library/product which will do the same thing. I'm sure most of you guys must have faced this problem. Appreciate your help Thanks Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Beans in JSP
I am trying to encapsulate all my db connection functionality inside a Java Bean and use that Bean inside my JSPages using the Bean tag. In some cases if i made the beans as session beans, for some reason i do not get page's content generated by JSP, instead i get a blank page. To resolve the issue i had to rename my bean in the bean tag(which eventually means changing my page) or recycle/restart Jrun(I use Apache & Jrun). So i wonder if its a problem with Jrun, I think it leaves orphaned beans/classes around. Have any of you experienced this problem. Also when is a session bean destroyed, my guess would be when the session is complete. Am i right thanks for your time Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Re: offtopic:JavaScript & Security
Ross, If i am going to do validation on the frontend and do the same on the backend/middle tier as well, then im wondering whether i should use JavaScript at all to do client side validation. In any case if Im going to do serverside validation then I might as well do the validation only on the serverside to avoid any overhead on the clientside. So does all these websites which do ClientSide Validation also do the same on the ServerSide. Thanks for your time Sanjay -Original Message- From: Ross Dyson [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 21, 1999 11:15 AM To: Radhakrishnan, Sanjay (c); [EMAIL PROTECTED] Subject: RE: offtopic:JavaScript & Security This is a favourite way to hack web sites, when they rely only on Javascript to secure them. The user only has to turn off javascript in their browser to avoid any checking. You must validate front and back!! Javascript gives instant feedback only. -Original Message- From: A mailing list about Java Server Pages specification and reference [mailto:[EMAIL PROTECTED]]On Behalf Of Radhakrishnan, Sanjay (c) Sent: Tuesday, December 21, 1999 16:14 To: [EMAIL PROTECTED] Subject: offtopic:JavaScript & Security We are planning to develop a system for delivering reports over the web. HTML and JavaScript would be used in doing the frontend interface. My question to the group is this how secure is JavaScript. I understand that one of the most common Uses of JavaScript is doing client side validation. But the problem(it maynot be) that i see with JavaScript is that an intelligent user can do a view source on the browser change the JavaScript, and hence could change the validation rule and could enter incorrect data into the system. Is this a possibility or am i missing something here. Thanks for your time Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
offtopic:JavaScript & Security
We are planning to develop a system for delivering reports over the web. HTML and JavaScript would be used in doing the frontend interface. My question to the group is this how secure is JavaScript. I understand that one of the most common Uses of JavaScript is doing client side validation. But the problem(it maynot be) that i see with JavaScript is that an intelligent user can do a view source on the browser change the JavaScript, and hence could change the validation rule and could enter incorrect data into the system. Is this a possibility or am i missing something here. Thanks for your time Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Off topic: Classes in a package?
I am writing a utility program in java which should do the following. Given a package name it should display all classes in that package. Is there a way by which i can do that in java? Thanks for your time Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
Tabbed panes in HTML
I am trying to create a couple of pages with JSP for one of the pilot projects. I am trying to create tabbed panes in my html page. For example if you take a look at cicuitcity.com the main page has a lot of tabs which are actually gifs. Clicking on a tab(or gif) brings up a different page which sort of simulates the effect that its a tab control. My question is this does anybody know if i can get readymade gifs which can be used in the same way described above. I am not a Graphic designer and i really do not want to spend time designing gifs. Probably i should be asking this question to a HTML user group. But i thought this would be a good place to start since my project involves Java Server Pages. Thanks for your time Sanjay === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". FAQs on JSP can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html
