Ambiguity in JSP

Question

Hi !!,
I have a query on jsps.
In my project we have an enhancement where we are trying to do the following :
1) We are having some existing users who can change their password through http://localhost/eportal/ChangePassword.jsp
2) [ENHANCEMENT] The new users, will login into loginhandler.jsp and then will change the password in ChangePassword.jsp.
We are maintaining the same ChangePassword.jsp in both the cases. However, we are encountering an issue here :
- The existing and new users are differentiated based on an error code.
For new users, we are capturing the errorcode in loginhandler.jsp using
String resul=loginRes+" ";
          session.setAttribute("errorcode",resul);
Then in ChangePassword.jsp we are doing the following :
String ercode=(String)session.getAttribute("errorcode");
String errcode=ercode.trim();
int erCode = Integer.valueOf(errcode).intValue();
//1111 is the errorcode of new user
if(erCode==1111){
------ execute below--------
For new users, this code is working perfectly fine. However, it is failing in case of existing users.
Here, when we are accesssing ChangePassword.jsp direclty incase of existing users, the getAttribute() doesnt know what it has to get and hence throws a Nullpointer exception.
We want to add such a condition that will skip the getAttribute() code in ChangePassword.jsp whenever we are accessing it for Existing Users and behave normally in case of new users.
Can you help me on this. If you need any inputs, then please let me know.

Answer 1

Add a check for null/non-null. How it looks depends on your functionality. Do you have an error code "1111" which signals special treatment, and after the special treatment new users and existing users behave the same? Then this may work:
String errcode = (String)session.getAttribute("errcode");
if ("1111 ".equals(errcode)) {
  //do new user work
//do all user workDo you have a situation where the new user gets one functionality and all other users get different?
String errcode = (String)session.getAttribute("errcode");
if("1111 ".equals(errcode)) {
  //do new user work
} else {
  //do all other user work
}Or maybe you have multiple error codes which should be treated differently:
String errcode = (String)session.getAttribute("errcode");
if ("1111 ".equals(errcode)) {
  //do new user work
} else if ("[other known error codes]".equals(errcode)) {
  //do other error handling work here
} else { /* or } else if (errcode == null) {  But be aware of what you want to
             happen in the default case when all if/else if are false... */
  //do existing user work here
}And none of this should be in a JSP. The JSP should be for display only. Put this sort of work inside a Servlet or a JavaBean.
Edited by: stevejluke on Jun 19, 2008 11:06 AM