LinkBuilder.scala

import scala.collection.mutable.MultiMap
import java.net.URLEncoder
import scala.collection.mutable.{HashMap, StringBuilder, HashSet}
import scala.collection.mutable.StringBuilder;

class LinkBuilder(path : String) {

    private var attributes = new collection.mutable.HashMap[String, collection.mutable.Set[String]]() with collection.mutable.MultiMap[String, String];
    
    override def toString() : String = {
        var url : StringBuilder = new StringBuilder(path);
        var separator = "?";
        
        attributes.foreach { case (name,value) =>  
            value.foreach { v =>
              url append separator append name append "=" append 
                URLEncoder.encode(v, "utf-8");
            
              separator = "&";
            }
        }
        url.toString
    }
    
    def +(name : String, value : String) : LinkBuilder = {
        if (value != null) {
            val entry = new HashSet[String]
            entry += value;
            
            if (attributes contains name) {
              attributes(name).foreach { v =>
                entry += v;
             }
            }
            
            attributes += name -> entry;
        }
        this;
    }
}

Tein oman version tän inspaamana https://gist.github.com/869689. Noi mutable mapit on vähän mystisiä...