Re: converting some VB code to Java..

From:
"Bjorn Abelli" <bjorn_abelli@DoNotSpam.hotmail.com>
Newsgroups:
comp.lang.java.help
Date:
28 May 2006 18:38:15 +0200
Message-ID:
<4479d1f7$1_3@x-privat.org>
"maya" wrotw...

Hi all, long time no see....:) I'm trying to learn AJAX,
am following this tutorial,
http://www.w3schools.com/ajax/ajax_source.asp


Looking at the ASP-sample on that page, I wouldn't rely too much on that
tutorial. I think it's a bit flawed...

I need the VB script code in this pg converted to JSP
so I can play around with this in my Tomcat..
got as far converting the getParam line.. (I assume that's what

  q=ucase(request.querystring("q"))

is..)


That's correct.

and I suppose the following is an array
(although don't see ref. to it further down..)


[snipped array initalization]

A reference to that array do exist, in a loop where each element is compared
to the parameter 'q'.

but the conditionals are throwing me off a bit...
(man, no semi-colons, no curly braces, looks a bit messy...)


Not only that, AFAIK, 'mid' is in VbScript what 'substring' is in Java,
which means that the logic of the loop is flawed.

if len(q)>0 then
  hint=""
  for i=1 to 30
    if q=ucase(mid(a(i),1,len(q))) then

    ' the line above makes a substring of 'a[i]'
    ' starting from the first position, with the
    ' max length of 'q'

    ' The flaw in the logic is that if that substring
    ' *equals* to 'q', the rest of the loop doesn't make
    ' any sense...

      if hint="" then
        hint=a(i)
      else
        hint=hint & " , " & a(i)
      end if
    end if
  next
end if

------------------------------------------------------
I don't do JSP very much, but something similar with a
servlet could look like:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class AjaxServlet extends HttpServlet
{
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
    throws ServletException, IOException
    {

        PrintWriter out = response.getWriter();

        String[] a = new String[30];

        a[1] = "Anna";
        a[2] = "Brittany";
        a[3] = "Cinderella";
        a[4] = "Diana";
        a[5] = "Eva";
        a[6] = "Fiona";
        a[7] = "Gunda";
        a[8] = "Hege";
        a[9] = "Inga";
        a[10] = "Johanna";
        a[11] = "Kitty";
        a[12] = "Linda";
        a[13] = "Nina";
        a[14] = "Ophelia";
        a[15] = "Petunia";
        a[16] = "Amanda";
        a[17] = "Raquel";
        a[18] = "Cindy";
        a[19] = "Doris";
        a[20] = "Eve";
        a[21] = "Evita";
        a[22] = "Sunniva";
        a[23] = "Tove";
        a[24] = "Unni";
        a[25] = "Violet";
        a[26] = "Liza";
        a[27] = "Elizabeth";
        a[28] = "Ellen";
        a[29] = "Wenche";
        a[30] = "Vicky";

        String q = request.getParameter("q").toUpperCase();
        String hint = "";

        if (q != null && q.length() > 0)
        {
            for (int i = 0; i < 30; i++)
            {

// Possible flaw in logic within the loop,
// see above...

                if ( q.equals(a[i]
                      .substring(0, Math.min(q.length(), a[i].length())
                      .toUpperCase()) )
                {
                    if (hint.equals(""))
                    {
                        hint = a[i];
                    }
                    else
                    {
                        hint += " , " + a[i];
                    }
                }
            }
        }

        if (hint.equals(""))
        {
            out.print("no suggestion");
        }
        else
        {
            out.print(hint);
        }
    }
}
---------------------------------------------

Then it's up to you to transform that into JSP... :-)

However, if I might guess, the loop possibly should look more like:

---------------------------------------------

  if (q != null && q.length() > 0)
  {
      for (int i = 0; i < 30; i++)
      {

// -> contains instead of equals?

          if ( q.contains(a[i].toUpperCase()) )
          {
              if (hint.equals(""))
              {
                  hint = a[i];
              }
              else
              {
                  hint += " , " + a[i];
              }
          }
      }
  }

---------------------------------------------
....or like this:

  if (q != null && q.length() > 0)
  {
      for (int i = 0; i < 30; i++)
      {
          if ( q.equals(a[i]
                .substring(0, Math.min(q.length(), a[i].length())
                .toUpperCase()) )

             hint = a[i];
             break; // <- break out when found...
          }
      }
  }
---------------------------------------------
On the other hand, if the array (or whatever collection) had consisted of
several elements that *started* similarly (e.g. "Hege" *and* "Helga"), it
would make more sense. Otherwise, the tutorial just had a bad example...

/// Bjorn A

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