Ananth,
What is the servlet supposed to be doing? Where is the HashMap variable
defined and what is it supposed to contain? Usually synchronized methods
are used to guard sections of code that might have race conditions (two
different threads accessing and modifying a shared variable) Most servlets
shouldn't have any shared variables or variables that have class scope. If
you have a lot of them, then you might have to think about redesigning your
apps. The changes could be as simple as making the vars method vars.
-Richard
At 02:57 PM 8/24/01 +0800, you wrote:
>thanks richard
>You visualized the whole scenario by just glancing a function. SIMPLY GREAT
>Yes u r write I was actually seeing the values of the variable
>parameterOutput using the SOP and just commented it when it was no longer
>need.
>Ive taken ur comment especially the design issue into my mind and lemme
>think abt it. Ur comments were really good ones.
>Yes as u said I was passing the HttpServlet response or request object
>itself to invoking programs to decide upon whether the GET or POST method of
>the servlet needs to be invoked.
>I understood ur synchronized explanation. Can u just throw some more light
>with simple example if u have time.
>bCos
>a) Iam using hashmap across the site which i think becomes heavy and calls
>for some re-thinking
>b) Iam using Class.forName("the java class") and obj.getInstance() to get
>the instance of the business object. All over here i have used synchronized
>to make sure the values obtained across the pages are consistent.
>But now i have to think abt 350 programs like this in the site for removing
>the httpservlet instance object being passed across the site.:). Also
>occassionally i receive an error saying
>that "The business object is not instantiated-->account.GET". Upon
>refreshing its come up. Pretty strange.
>
>regards
>ananth
>
>
>
>
>-----Original Message-----
>From: Richard Yee [mailto:[EMAIL PROTECTED]]
>Sent: Friday, August 24, 2001 2:28 PM
>To: [EMAIL PROTECTED]
>Subject: Re: Out Of Memory Space Error....StringBuffer.append problem
>
>
>Ananth,
>A couple of comments on your code:
>1) I am almost certain that the method should not be synchronized. There
>aren't any variables or data structures that are being used that are shared.
>2) It is a bad practice to have a data structure like HttpServletRequest as
>a parameter to a domain object especially when the only value used from the
>data structure is the value of the String returned by the
>req.getParameter("TOWHERE") method call. This practice is called "Exposing
>Presentation-Tier Data Structures to Domain Objects" from pg. 51 of Core
>J2EE Patterns) The reason this is a bad practice is that it needlessly
>couples two distinct aspects of the application. It also limits the
>ability for the function to be reused b/c it makes the function protocol
>or tier-specific. In this case, the req variable could just be replaced by
>a String variable called toWhere or another meaningful name.
>3) The counter variable is being used just as a flag and should therefore
>be replaced with a boolean.
>4) There are several instances where you use 'new String("displayHeader")'
>. I think all of these can be replaced with just "displayHeader".
>5) The getOrPost int parameter should just be a boolean since it only has
>two values. Constants.HTTP_GET or Constants.HTTP_POST. A more meaningful
>name for the variable would be isPost or isGet. It would make the code
>more understandable
>6) The parametersOutput variable seems to be unused unless there was
>additional code that you cut. It seems to me that this variable is getting
>appended to itself repeatedly. You might want to put a
>System.out.println("parametersOutput = " + parametersOutput); in your code
>to see what the value is.
>7) The entire function can be distilled to the following:
>
> >private void fillSetHeaderProperty(HashMap map, String toWhere,boolean
>isGet)
>{
> int i = 0;
> toWhere = toWhere.trim();
> if (isGet)
> toWhere = toWhere + ".GET";
> else
> toWhere = toWhere + ".POST";
> while (i<Constants.RESTRICT_HEADER_DISPLAY.length)
> {
> if
>(toWhere.equals(Constants.RESTRICT_HEADER_DISPLAY[i].trim()))
> {
> if (isGET)
> > map.put("displayHeader","N");
> else
> map.put("displayHeader","Y");
> break;
> }
> i++;
> }
> if (i == Constants.RESTRICT_HEADER_DISPLAY.length)
> map.put("displayHeader","Y");
>}
>
>
>
>At 10:20 AM 8/24/01 +0800, you wrote:
> >I have zeroed upon a simple function to depict the scenario Iam facing.
> >There are multiple other functions like this..
> >
> >This function fills the header part of the page with parameters fetched
>from
> >the HashMap and also depending upon the get or post method called by the
> >invoker servlet.
> >
> >
> >////////////////////Function Begin
> >
> > private synchronized void fillSetHeaderProperty(HashMap map,
> >HttpServletRequest req,int getOrPost)
> > {
> >
> > String tempStr=null;
> > String toWhere=req.getParameter("TOWHERE");
> > String tempStr1 = null;
> >
> > int counter=0;
> >
> > for(int i=0; i < Constants.RESTRICT_HEADER_DISPLAY.length;
> >i++)
> > {
> > tempStr = Constants.RESTRICT_HEADER_DISPLAY[i];
> >
> > if(getOrPost==Constants.HTTP_GET)
> > {
> > tempStr1 = toWhere + ".GET";
> > if
> >((tempStr1.trim()).equals(tempStr.trim()))
> > {
> > map.put(new
>String("displayHeader"),
> >"N");
> >
> >///////////////////////////////////////////////////////////////////////////
>/
> >/////////////////////
> >
> >//COMMENTED BY ANANTH THE PARAMETERVARIABLE I SUSPECT AND I COMMENTED
> >FROM HERE
> >
> >
> >
> >//parametersOutput = parametersOutput + "<br><b>Name:</b> " +
>new
> >String("displayHeader") + " <b>Value:</b> N" ;
> >
> >
> >
> >/////////////////////////TILL HERE
> >
> >
> >
> > counter =counter + 1;
> > }
> > }
> > else
> > {
> > tempStr1 = toWhere + ".POST";
> >
> > if
> >((tempStr1.trim()).equals(tempStr.trim()))
> > {
> > map.put(new
>String("displayHeader"),
> >"N");
> >
> >
> >
> >//COMMENTED BY ANANTH SIMILARLY HERE ALSO
> >// parametersOutput = parametersOutput
> >+ "<br><b>Name:</b> " + new String("displayHeader") +
> >" <b>Value:</b> N" ;
> >
> >
> > counter=counter+1;
> > }
> > }
> > }
> > if (counter==0)
> > {
> > map.put(new String("displayHeader"), "Y");
> >
> >
> >//COMMENTED BY ANANTH
> >// parametersOutput = parametersOutput + "<br><b>" +
> >tempStr + "</b><br><b>" + tempStr1 + "</b><b>Name:</b> " + new
> >String("displayHeader") + " <b>Value:</b> Y" ;
> >
> > }
> > }
> >
> >
> >
> >
> >
> >
> >/////////////////Function Ends
> >
> >
> >Suggest me whether this is the "solution" or anyother is there. So far i
>did
> >not receive the error and the site runs pretty fast.This variable
> >"parametersOutput" i was using to view the parameters of the pages I left
>it
> >just by commenting the out.println. But the variable was getting populated
> >again and again and may be it threw that error. Correct me whether the
> >solution is right.
> >
> >thanks
> >ananth
> >
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