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Checking String length

Hi,

I just basically want to see if my varibles have a value or not, So I use .Length.  I'm just not sure if this is the best way to do this, as I keep getting a null pointer error.

<%
String varManifest = (String)request.getParameter("Rec_Manifest");
%>
<tr><td>Manifest&nbsp;&nbsp;</td>  <td><%if (varManifest.length() >0 ){ %><input type='checkbox' checked DISABLED><%} else {%><input type='checkbox' unchecked DISABLED><%}%></TD> <td nowrap><%=varManifest%></td></tr>

All I want to show is a ticked checkbox if there is a value else  show it unticked.
0
Pigdogmonster
Asked:
Pigdogmonster
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1 Solution
 
searlasCommented:
If you check for null and set to the empty string you'll avoid the NullPointerException's.
Are you using Struts at all?  If so, you may want to look at the logic:present/notPresent and logic:empty/notEmpty tags.
<%
String varManifest = (String)request.getParameter("Rec_Manifest");
if (varManifest == null) {
  varManifest = "";
}
%>
<tr>
  <td>Manifest&nbsp;&nbsp;</td>
  <td><input type='checkbox' <% if (varManifest.length() > 0) %>checked<% } %> DISABLED></td>
  <td nowrap><%=varManifest%></td>
</tr>
0
 
jarasaCommented:
Searlas what is this for?? <% } %>

Anyway could probably be easier, at least shorter this:

<tr>
  <td>Manifest&nbsp;&nbsp;</td>
  <td><input type='checkbox' <% (String)request.getParameter("Rec_Manifest")==null?%><%:((String)request.getParameter("Rec_Manifest")).length>0?%>checked<%:%> DISABLED></td>
  <td nowrap><%=(String)request.getParameter("Rec_Manifest")%></td>
</tr>

Javier
0
 
jarasaCommented:
:c)

Thanks
0
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searlasCommented:
Dagnamnit, missed out on 20 points for missing a curly:
<tr>
  <td>Manifest&nbsp;&nbsp;</td>
  <td><input type='checkbox' <% if (varManifest.length() > 0) { %>checked<% } %> DISABLED></td>
  <td nowrap><%=varManifest%></td>
</tr>
0
 
searlasCommented:
Hey jarasa,

Doesn't your answer behave differently to pigdogmonster's original code (and I'm not talking about not throwing a NPE)

i.e. if the parameter is missing, the checkbox is not disabled.  But in the original question the checkbox is always disabled.

Ignoring the syntax errors, must say I've never seen tertiary operators split up and used like that in a JSP.  That's one sick trick... (IMHO, of course :-)




0
 
jarasaCommented:
To tell you the truth searlas, I thought pigdog was goin to give you the points.

I shouldn't opened my mouth.

Sorry, your answer was fine.

Javier


0
 
jarasaCommented:
I haven't tryed but I think that the DISABLED will get printed always

is like doing this in just Java Code

StringBuffer Print = "";
Print.append("<tr><td>Manifest&nbsp;&nbsp;</td><td><input type='checkbox'");
(String)request.getParameter("Rec_Manifest")==null?Print.append(""):((String)request.getParameter("Rec_Manifest")).length>0?Print.append("checked"):Print.append(" DISABLED></td><td nowrap>);
Print.append((String)request.getParameter("Rec_Manifest")+"</td></tr>");

out.println(Print.toString());

Isn't it??

Javier
0
 
jarasaCommented:
Sorry I ment this:

StringBuffer Print = "";
Print.append("<tr><td>Manifest&nbsp;&nbsp;</td><td><input type='checkbox'");
(String)request.getParameter("Rec_Manifest")==null?Print.append(""):((String)request.getParameter("Rec_Manifest")).length>0?Print.append("checked"):Print.append("");
Print.append(" DISABLED></td><td nowrap>");
Print.append((String)request.getParameter("Rec_Manifest")+"</td></tr>");

out.println(Print.toString());

Javier
0
 
jarasaCommented:
>Ignoring the syntax errors, must say I've never seen tertiary operators split up and used like that in a JSP.  That's one sick > trick... (IMHO, of course :-)

To tell you the truth me either, but look wild isn't it??

I'm a one line developer :c)) That's make the hackers think twice to ge my code ;cP

Javier
0
 
PigdogmonsterAuthor Commented:
Thanks for all the help Guys, I really appreciate it! :-)

I did actually mean to give the point to Searls as that is the code I've used!,  :-/
0
 
jarasaCommented:
Well then I should refound it to him, if he wants of course. Do you Searlas?
Javier
0
 
searlasCommented:
Thanks for the offer 'n' honesty.  I'll live without them...

Cheers
0
 
jarasaCommented:
:c)
0
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