Servlet chaining possibility

Hi, A reply to one of the earlier messages, says "servlet chaining is currently not available". does it mean it would be available in future versions or do we have support for it in any of the currently available, recently released versions?

i just wondering, why you want to chain the servlets in what way, is that
          the servlet application is in someway already chained in by itself.
          it would be little use in my mind to have chained servlet.
          just my opinon
          Frank
          Mahesha <[email protected]> wrote in message
          news:40d8c8fc$1@mktnews1...
          > Hi, A reply to one of the earlier messages, says "servlet chaining is
          currently not available". does it mean it would be available in future
          versions or do we have support for it in any of the currently available,
          recently released versions?

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How to Configure a Servlet Chain Using MIME Types with weblogic5.1?

Hi ,
          I want to configure a servlet(cocoon) in weblogic 5.1 such that the
          servlet so configured is invoked each
          time a response with the mime-type "text/xml" is generated.
          1.) will weblogic support to configure a servlet with a particular
          mime-type so that it post-process any
          servlet's response with the corresponding mime-type?
          2.) if not what is the alternative?
          Thanks
          sumanth
          [sumo.vcf]


We suggest that use the request dispatcher interface instead. Servlet
          chaining is not a standard's based possibility.
          Michael Girdley
          WLS Product Manager
          Sumanth Chinthagunta <[email protected]> wrote in message
          news:[email protected]..
          > Hi ,
          > I want to configure a servlet(cocoon) in weblogic 5.1 such that the
          > servlet so configured is invoked each
          > time a response with the mime-type "text/xml" is generated.
          > 1.) will weblogic support to configure a servlet with a particular
          > mime-type so that it post-process any
          > servlet's response with the corresponding mime-type?
          > 2.) if not what is the alternative?
          >
          > Thanks
          > sumanth
          >

Servlet chaining problem..

import java.io.*;
    import javax.servlet.*;
    import javax.servlet.http.*;
    public class Deblink extends HttpServlet {
      public void doGet(HttpServletRequest req, HttpServletResponse res)
                                   throws ServletException, IOException {
        String contentType = req.getContentType(); // get the incoming type
        if (contentType == null) return; // nothing incoming, nothing to do
        res.setContentType(contentType); // set outgoing type to be incoming type
        PrintWriter out = res.getWriter();
        BufferedReader in = req.getReader();
        String line = null;
        while ((line = in.readLine()) != null) {
          line = replace(line, "<BLINK>", "");
          line = replace(line, "</BLINK>", "");
          out.println(line);
      public void doPost(HttpServletRequest req, HttpServletResponse res)
                                    throws ServletException, IOException {
        doGet(req, res);
      private String replace(String line, String oldString, String newString) {
        int index = 0;
        while ((index = line.indexOf(oldString, index)) >= 0) {
          // Replace the old string with the new string (inefficiently)
          line = line.substring(0, index) +
                 newString +
                 line.substring(index + oldString.length());
          index += newString.length();
        return line;
What is pre request fo above code to work.
I had tried this many time but it is not working, what will be calling servlet look like

And can you explain why your title is "Servlet chaining problem"?

Servlet Chaining and OAS 4.0.8.1

I am using the Request Dispatcher Concept for my application where a servlet either initiates a bean or calls another servlet. I believe I cannot test it from JDeveloper.But does OAS 4.0.8.1 support servlet chaining. Very Critical. if yes? Please let me know where I can find the necessary documentation.
Thanks

More info ...
I enable logging and found the following error
Unable to initiate threads: cannot find class java/lang/Thread.

Does weblogic server have Servlet chaining concept?

I saw JRun which has the servlet chaining function. Does anyone know how to
          do it in the weblogic server?
          Thank you.
          li


WLS does not support Servlet Chaining
          Kumar
          li wrote:
          > I saw JRun which has the servlet chaining function. Does anyone know how to
          > do it in the weblogic server?
          >
          > Thank you.
          >
          > li

Can WebLogic do Servlet chaining?

Is there any way to do servlet chaining, or more specifically, for a servlet
          to process the output of another servlet efficiently in WebLogic?
          Sure a servlet can make another HTTP request on its own servlet engine but
          that seems way too inefficient and heavy handed.
          J.
          James Strachan
          =============
          email: [email protected]
          web: http://www.metastuff.com


Check out XSPs from cocoon. xml.apache.org
          -- bk
          James Strachan wrote:
          > JSP includes go straight to the HTTP response - there's no way of
          > redirecting them to some internal buffer for post processing. (*)
          >
          > I'd like to be able to do simple Servlet chaining at the Servlet or JSP
          > level. i.e. I want to post process the output of one servlet / JSP page to
          > do things like caching or XSL styling. This is a totally reasonable request
          > IMHO. Imagine a complex portal with alot of included JSP files - I'd like to
          > be able to cache whole chunks of the page - a chunk may have many includes
          > inside it..
          >
          > Right now there is no way of doing such a thing in WebLogic AFAIK. You have
          > to go through every JSP file and add caching / styling to it rather than
          > being able to 'pipeline' or 'servlet chain' which is less than ideal. (Also
          > remember there is a 64K code size limit on the bytecode that can exist in a
          > Java class - so JSP files should be kept small to void hitting this
          > barrier). I can't quite believe noone else has hit this problem.
          >
          > There are workarounds such as to do the include using seperate internal HTTP
          > requests, RMI calls or JMS messages all of which seem to be far too
          > heavyweight.
          >
          > (*)
          > <aside>
          > One side effect of the JSP include always going straight to the response
          > means that you can't use WebLogics <cache> tag if you are using any kind of
          > JSP include. e.g. the following snippet doesn't work as expected :-
          >
          > <cache>
          > something
          > <jsp:include file="foo.jsp" flush="true"/>
          > something else
          > </cache>
          >
          > since you are not allowed to do an include inside a body tag,. Even if you
          > were the output of the include goes straight to the response, not the body
          > tag.
          >
          > So you have to close and reopen the cache tags around each include which may
          > break your XML complience for complex pages and is error prone and much more
          > inefficent to boot:-
          >
          > <cache>
          > something
          > </cache>
          > <jsp:include file="foo.jsp" flush="true"/>
          > <cache>
          > something else
          > </cache>
          >
          > </aside>
          >
          > --
          > J.
          >
          > James Strachan
          > =============
          > email: [email protected]
          > web: http://www.metastuff.com
          >
          > "Jaggu Dada" <[email protected]> wrote in message
          > news:[email protected]...
          > >
          > > Hi --
          > >
          > > Why not use JSP includes? The only servlet "chaining" that is
          > > reasonable
          > > is to use a servlet to process an initial request, and make some
          > > decision
          > > (based on the querystr, for example) then, without having written
          > > anything
          > > back to the client, do a server side redirect (with RequestDispatcher)
          > > to
          > > a servlet or JSP that does some work. If I understand you correctly,
          > > servlets
          > > were not designed to do what you are proposing.
          > >
          > > Hope this helps,
          > >
          > > -jaggu
          > >
          > > James Strachan wrote:
          > > >
          > > > Hi Joe
          > > >
          > > > Thanks for that. Sure that would work too though its probably a heavier
          > > > weight than just plain old HTTP.
          > > >
          > > > I was looking for something a little more lightweight such that I could
          > > > include 10-20 servlet chains per web page on a complex portal without
          > too
          > > > much performance hit. i.e. using synchronous servlet 'pipelining' to
          > > > generate complex pages without having to do many internal HTTP / JMS
          > > > requests.
          > > >
          > > > --
          > > > J.
          > > >
          > > > James Strachan
          > > > =============
          > > > email: [email protected]
          > > > web: http://www.metastuff.com
          > > >
          > > > "Joe Trung" <[email protected]> wrote in message
          > > > news:[email protected]...
          > > > >
          > > > > Hi Jim,
          > > > > I chain my servlets via jms: the queue is output/input bin
          > > > >
          > > > > Joe
          > > > >
          > > > >
          > > > > "James Strachan" <[email protected]> wrote:
          > > > > >Is there any way to do servlet chaining, or more specifically, for a
          > > > servlet
          > > > > >to process the output of another servlet efficiently in WebLogic?
          > > > > >
          > > > > >Sure a servlet can make another HTTP request on its own servlet
          > engine
          > > > but
          > > > > >that seems way too inefficient and heavy handed.
          > > > > >
          > > > > >J.
          > > > > >
          > > > > >James Strachan
          > > > > >=============
          > > > > >email: [email protected]
          > > > > >web: http://www.metastuff.com
          > > > > >
          > > > > >
          > > > > >
          > > > >

Is servlet chaining (filtering) supported?

For a given virtual name I would like to set up a chain of servlets
          (ProducerServlet, ConsumerServlet) so that the ServletInputStream of the
          ConsumerServlet contains the results of the ServletOutputStream of the
          ProducerServlet. The ConsumerServlet is in effect 'filtering' the results
          of ProducerServlet.
          eg. BrowserRequest --> ProducerServlet --> ConsumerServlet -->
          BrowserResponse
          Can this be done with WLS 5.1?
          The RequestDispatcher interface does not seem to satisfy these requirements?
          If I understand this interface correctly, it allows requests to be either
          'forwarded' (where the output of the forwarder is not used) or 'included'
          (where the included servlet inserts output in the stream). But it does not
          allow servlets to be connected in a producer-consumer chain.
          Am I missing something?
          Thank you.
          Marko.


Is there any way to achieve the same effect within the current spec?
          Marko.
          Winston Koh <[email protected]> wrote in message
          news:[email protected]...
          > Hey Marko, servlet chaining is not supported in WLS since its a
          proprietary
          > mechanism not specified in the current servlet/jsp specs
          >
          > thanx
          >
          > Winston
          > Marko Milicevic <[email protected]> wrote in message
          > news:[email protected]...
          > > For a given virtual name I would like to set up a chain of servlets
          > > (ProducerServlet, ConsumerServlet) so that the ServletInputStream of the
          > > ConsumerServlet contains the results of the ServletOutputStream of the
          > > ProducerServlet. The ConsumerServlet is in effect 'filtering' the
          results
          > > of ProducerServlet.
          > >
          > > eg. BrowserRequest --> ProducerServlet --> ConsumerServlet -->
          > > BrowserResponse
          > >
          > > Can this be done with WLS 5.1?
          > >
          > > The RequestDispatcher interface does not seem to satisfy these
          > requirements?
          > > If I understand this interface correctly, it allows requests to be
          either
          > > 'forwarded' (where the output of the forwarder is not used) or
          'included'
          > > (where the included servlet inserts output in the stream). But it does
          > not
          > > allow servlets to be connected in a producer-consumer chain.
          > >
          > > Am I missing something?
          > >
          > > Thank you.
          > >
          > > Marko.
          > > .
          > >
          > >
          > >
          >
          >

Java Servlet BUG (Possibly)-Servlet classname replaces retrieved doc name

I created a test servlet (TestServlet.java) which reads data from a file which could be pdf/doc/xls/zip etc and presents the file to the user for download. When the user clicks on the save option to save the file the default name before the file extension of the file in the save dialog box is always TestServlet. i.e. If the file being downloaded is BEA.doc the default name in the save dialog box is TestServlet.doc
The contents of the file(data in the file) are correct but the default name should be BEA.doc and not TestServlet.doc. I get the same result if the file is a pdf/xls or any other file type which is being downloaded.
We tested this in BEA Weblogic 8.1 and Tomcat and get the same results both places so this issue is not application server specific and seems like a bug to us.
The TestServlet.java file is below
package com.test;
import java.io.*;
import java.util.*;
import javax.servlet.http.*;
public class TestServlet extends HttpServlet
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        doPost(request,response);
    public void doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, java.io.IOException
        int count = 0;
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            File theFile = new File(fileName);
            if (theFile.exists())
                try
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                    wr = new ByteArrayOutputStream();
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                    response.setContentType("application/msword");
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                catch(Exception ex)
                    System.out.println(ex.getMessage());
            else
                response.setContentType("text");
                response.getWriter().write("no data");
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} I get the same results. i.e. The name of the document downloaded by the servlet is TestServlet.doc instead of BEA.doc which is what I have in c:\BEA.doc.

The web browser downloading this knows nothing about the file you are loading from disk and sending via the servlet. All it knows is that it requested via Http on the url TestServlet, and is getting something in return.
A quick google pulled up this link: http://builder.com.com/5100-6370-1027645.html
You might try this:
response.setHeader("Content-Disposition","inline;filename=\"BEA.doc\"");
good luck,
evnafets

Servlet chaining

Hi,
I am having three servlets. First servlet is receiving request
and after doing some processing it generates html and sends html
to user. Once user enters all details in requested page(html
page sent by servlet 1), he presses submit on that html.
At that time that html is calling another servlet(Servlet 2).
After receiving request from user, servlet 2 extract parameter
sent by user. Then it stores extracted parameter to database.
Depends upon one parameter (sent by user) servlet2 dispatch
request to servlet3.
Now I want to convert above servlets into portlet.
Can anybody tell me how to convert second servlet into portlet.
Because it is not shown in any page but still it receives
request. do some processing and send the response to third
servlet.
Do I need to change zone and jserv properties file for servlet2?
Do I need to enter servlet 2 in provider.xml where servlet 1 is
entered as portlet ?
Thanks in advance.
Biren

Hello,
What is the version of the weblogic server you are using ?
Regards
Anilkumar kari

Servlet chaining or reponse filtering

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          WL6?


If not, how can I do this under          >WL6?
          I do this:
          I create one controller servlet. then I create many command classes, they
          have a constructor and one execute(req, res) method, which throws my
          exception.
          in servlet's init(), I load these commands, and put them in hashmap. then in
          service() I call one of the command's execute(req, res) method.
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          session, analyze requests etc.

Can a HTML form send data to two servlets?

I would like to know if an HTML Form can send data to two servlets, I guess I am askin is that can the parameters be passed to two ACTION attributes??

Hmmmm, well I'm not sure if that is possible, but you could do something of the sort on the server side by chaining them.... the technieque is called Servlet Chaining
Hope this helps
Omer

How to maintain layout of process chain ?

Dear all,
Is maintaining the layout of a process chain possible?
Since a complicated process chain will be in a state very hard to see with the automatic layout by a system,I am looking for the way of maintaining the layout of process chain.
Even if a layout is edited legible and it saves it in the edit mode of a process chain, a layout will be changed after coming out from an edit mode once and checks again.
Best regards,
Takao

Hi Takao,
I have exactly the same problem.
Does anyone any tricks?
Regards,
Daniel

How to send array of bytes to a servlet and store it in a file

Hi,
How to send array of bytes to a servlet and store it in a file.
I am new to Servlets. if possible for any one, please provide the code.
Thanks,
cmbl

Through HTTP this is only possible with a POST request of which the encoding type is set to multipart/form-data. You can use Apache Commons FileUpload to parse such a multipart form data request into useable elements. From the other side (the client) you can use a HTML <input type="file"> element or a Java class with Apache Commons PostMethod API.
You may find this article useful: http://balusc.blogspot.com/2007/11/multipartfilter.html

Servlet and JSP in OAS

I'm developing web application with OAS
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JSP from servlet using "RequestDispatcher".
I downloaded JSP for OAS from www.olab.com.
In the Release note, there is a description
about RequestDispatcher, but I cannot
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null

wan (guest) wrote:
: Hi everyone,
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: 3. running JDeveloper DB Servlet wizard
: (oracle.jdeveloper.servlet.*) and Java Business Objects
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I wish Oracle would get with the times and put out a product that
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future.
Having us download Suns server to run servlets and JSP is
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null

RequestDispatcher.forward on OAS 4.0.8.1 for Servlet Communication

We are unable to pass request information from a servlet to another servlet or a JSP on OAS 4.0.8.1 whereas we have been able to achieve this
successfully in JDK using the same code.
Since Servlet Chaining is not supported in the JServlet of OAS, use the forward
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RequestDispatcher rd;
rd =getServletConfig().getServletContext().getRequestDispatcher(/testme1/USe
rvl
et);
rd.forward(request,response);
It didn't do anything with the forward method and nothing was logged in the log file. Anyone out there, please send help ASAP. Thanks.
null

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Servlet chaining possibility

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