ModularFormatting.scala
package servletExamples ;
import javax.servlet._ ;
import javax.servlet.http._ ;
import scala.xml._ ;
class ModularFormatting extends ScalaHttpServlet {
val headerMsg = Text("What follows is an example of modular formatting.");
val footerMsg = Text("Complicated layout tasks can be encapsulated and outsourced. Try to append `?message=Hello' to the URL");
/** helper function for the main page, provides header and a footer
*/
def page( ns:Seq[Node] ) = {
<html>
<head>
<title>ModularFormatting</title>
</head>
<body>
<h2>Welcome</h2>
<p>
{ headerMsg }
</p>
<p>
{ ns }
</p>
<hr/>
<p>
{ footerMsg }
</p>
<h2>Bye!</h2>
</body>
</html>
}
/** applies beautify to every element in a sequence
* we could also have used parens xs.map(beautify)
* we could also have omitted the dot and the delimiters `xs map beautify'
* we could also have used a for comprehension `for(x <- xs) yield beautify(x)
*/
def beautify( xs:Seq[Node] ): Seq[Node] = xs.toList.map { beautify };
/** this is a recursive procedure that adds some attributes to the tree
*/
def beautify( n:Node ):Node = n match {
case x @ <td>{ xs @ _* }</td> =>
<td bgcolor="#AAAAFF" color="#222255">{ xs }</td>
case <table>{ xs @ _* }</table> =>
<table align="center">{ beautify( xs ) }</table>
case Elem( ns, label, map, scope, xs @ _* ) =>
Elem( ns, label, map, scope, (xs.map { beautify }):_*)
case _ => n
}
/** this function will take a node and put it in a table
*/
def format( msg:Node ):Node = {
<table>
<tr>
<td>{ msg }</td>
</tr>
</table>
}
/** returns a highlighted text node with the string given as arguemnt. if it
* is null, supplies a default string.
*/
def getMessage( x:String ) = {
if( x == null )
<h1> This could be YOUR message ! </h1>
else
<h1> { x } </h1>
}
/** the entry method
*/
def doGetXML( req:HttpServletRequest ) = {
val theMessage = getMessage( req.getParameter("message") );
beautify( page( format( theMessage )));
/* page( List( format( theMessage ))); */
}
}