calling a bean function using jstl

[Pradyut Bhattacharya]

Hi

i m calling a bean function and getting the error
The function ast must be used with a prefix when a default namespace is not specified

I m using using glassfish v2.1
I have the bean

 
package newa;

public class CounterBean {
    int count;
    String name = "Testing this";

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public int getCount() {
        return count;
    }
    public void increaseCount() {
        count ++;
    }

    public String ast() {
        return "this";
    }

}

The taglib

   

<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd">
  <tlib-version>1.0</tlib-version>
  <short-name>newtag_library</short-name>
  <uri>/WEB-INF/tlds/newtag_library</uri>

<function>

         <name>string</name>

         <function-class>newca.CounterBean</function-class>

         <function-signature>String ast()</function-signature>

    </function>
    </taglib>

 

in jsp im having

 
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="/WEB-INF/tlds/newtag_library" prefix="u" %>

${u.ast()} 

  

the line ${u.ast()} gives the error message (thanks to Bear Bibeault)

 

type Exception report

message

descriptionThe server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: /jstltest.jsp(35,10) PWC6296: The function ast must be used with a prefix when a default namespace is not specified
   

else everything works fine such as

  
<jsp:useBean id="simple" class="newa.CounterBean" scope="session">


        </jsp:useBean>

        <jsp:getProperty name="simple" property="name" />
        <jsp:setProperty name="simple" property="name" value="testing"  />
        ${simple.name}

  

Any help

Thanks
Pradyut

[Bear Bibeault]

Pradyut Bhattacharya wrote: the line ${u.ast()} gives the problem

In the future, please be sure to include the error message -- not just say "gives a problem". (Please read this for more information.)

But in this case, I can tell you that the problem is that EL functions must be static. You can't call instance methods.

  
        <jsp:getProperty name="simple" property="name" />
        <jsp:setProperty name="simple" property="name" value="testing"  />

Why are you using getProperty in place of the EL?

[Pradyut Bhattacharya]

thanks for the fast reply

changed the code to

  

public static String ast() {
        return "this";
    }

  

but still could not get solved. The same error message

   
type Exception report

message

descriptionThe server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: /jstltest.jsp(35,10) PWC6296: The function ast must be used with a prefix when a default namespace is not specified

 

thanks for quoting the getProperty but i was just showing they are working just fine...

regards
Pradyut

[Bear Bibeault]

You need to use the TLD's namespace to invoke the function.

[Pradyut Bhattacharya]

could not understand tld namespace or wheres it located...

new to tld and namespaces :-(

[Bear Bibeault]

You created the namespace when you mapped the TLD:

<%@ taglib uri="/WEB-INF/tlds/newtag_library" prefix="u" %>      

So to call the function:

$(u:ast()}    

By the way, the URI you chose doesn't follow the usual convention. It should look like a URL (even though it's not a URL) using a domain that you own. That way, there's never any chance of it conflicting with some other library's URI.

[Pradyut Bhattacharya]

Changed the uri to "http://pradyut.dyndns.org/newtag_library"

Thanks but still no change... the same error message

[Bear Bibeault]

You'll need to show your new files.

Are you sure that you are using a colon and not a dot to separate the namespace from the function name?

[Pradyut Bhattacharya]

wow.. i didnt know the use of colons like that...
well the new exception thrown is...

 
org.apache.jasper.JasperException: /jstltest.jsp(35,10) PWC6297: The function ast cannot be located with the specified prefix
   

[Bear Bibeault]

That's because it's not declared in your TLD. You must add a function element to define the function otherwise how is the JSP engine supposed to know anything about it?

[Pradyut Bhattacharya]

but in my tld i have

 
<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd">
  <tlib-version>1.0</tlib-version>
  <short-name>newtag_library</short-name>
  <uri>http://pradyut.dyndns.org/newtag_library</uri>
<function>

         <name>stringToBool</name>

         <function-class>newca.CounterBean</function-class>

         <function-signature>String ast()</function-signature>

    </function>

</taglib>


   

[Pradyut Bhattacharya]

sorry about that... now my tld is...

  
<function>

         <name>ast</name>

         <function-class>newca.CounterBean</function-class>

         <function-signature>java.lang.String ast()</function-signature>

    </function>

</taglib>

  

and in jsp i m calling

 

${u:ast()}

   

and still the error message

  

org.apache.jasper.JasperException: PWC6299: The class newca.CounterBean specified in TLD for the function u:ast cannot be found: newca.CounterBean
  

please rescue...

[Bear Bibeault]

Looks pretty clear to me; the class cannot be found. Did you compile the bean and put the class file in the correct location?

[Pradyut Bhattacharya]

thanks Bear Bibeault

you rocked it!!!

the tld should be

   

<function>

         <name>ast</name>

         <function-class>newa.CounterBean</function-class>

         <function-signature>String ast()</function-signature>

    </function>

 

[Varun Selvanathan]

This is the late comment.
I also found this same problem.
I got the solution by defining the method as static.