The ternary operator and JSP

This interesting bit of JSTL for JSP is worth writing about.

Background: The ternary operator allows you to combine an if-then-else statement into one line using a bunch of symbols. It makes code a bit harder to read, but it also makes it look cool.

I can turn this:

  not empty


  empty

into this:

It even parses variables for output:

And you don’t even need the c:out:

${not empty somevariable ?  somevariable: 'empty'}

Old hat yes, but I thought an interesting tidbit to write about!

http://steveswinsburg.wordpress.com/2008/09/04/the-ternary-operator-and-jsp/

Evaluate empty or null JSTL c tags

You can use the  or  for this.

 test="${empty var1}">
    var1 is empty or null.

 test="${not empty var1}">
    var1 is NOT empty or null.

or

     test="${empty var1}">
        var1 is empty or null.
    
    
        var1 is NOT empty or null.
    

The ${not empty var1} can also be done by ${!empty var1}.

To learn more about those ${} things (the Expression Language, which is a separate subject from JSTL),check here.

http://stackoverflow.com/questions/2811626/evaluate-empty-or-null-jstl-c-tags