Creating custom JSP Tags & passing spring controller data to them.

[veraction]

I have a Controller which returns a custom object of type Course:

return new ModelAndView( getSuccessView(), "course", myCourseObject );

Then, in my JSP view, I try to output it by:

<courses:courselist coursesVar="${course}"></courses:courselist>

Here is my tld file:

<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN"
                           "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">
<taglib>
    <tlibversion>1.0</tlibversion>
    <jspversion>1.1</jspversion>
    <shortname>courses</shortname>
    <info>An tag library for use with the Course Registration System</info>
    <tag>
        <name>courselist</name>
        <tagclass>courses.util.CourseListingTag</tagclass>
        <info>Prints a listing of courses in a pretty table</info>
        <attribute> 
            <name>coursesVar</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
    </tag>
</taglib>

Then, in my actual tag, I am attempting to output information about this object:

@Override
	public int doStartTag() throws JspException {
		logger.debug( "doStartTag -- with coursesVar= "+ coursesVar );
		
		StringBuffer buffer = new StringBuffer();
		
		Object obj = ExpressionEvaluationUtils.evaluate("coursesVar", this.coursesVar, Course.class, pageContext);
		if( obj == null ) { buffer.append( "courses attribute null"); }
		else { buffer.append( "courses attribute not null"); }
		buffer.append( "<br>obj: " + obj + " as: " + obj.getClass()+ "<br>" );
		
		try {
			pageContext.getOut().println( buffer.toString() );
		} catch (IOException e) {
			logger.error( "IOException in CourseListingTag!");
			throw new JspException( "IOException when starting courselisting tag", e );
		}
		return EVAL_BODY_INCLUDE;
	}

Trying to access this controller, I receive this exception:

javax.servlet.ServletException: Attribute value "courses.model.entities.Course@1917a08" is neither a JSP EL expression nor assignable to result class [courses.model.entities.Course]

Eventually, once I figure out how to do this, I want to make it so I can use my couses:courselisting tag to output a set of Course objects retrieved from Hibernate in a nice table.

Any ideas on how to make this work? Thanks

[veraction]

Problem Solved
I just decided to not use the ${} syntax anymore. I just directly pass in the string name of the attribute:

<courses:courselist coursesVar="courses"/>

Then, I retrieve it by using this:

Object o = pageContext.findAttribute( coursesVar );