String FromTo

public String str_replace(String from,String to,String source) {    
     StringBuffer bf= new StringBuffer("");
     StringTokenizer st = new StringTokenizer(source,from,true);
     while (st.hasMoreTokens()) {
       String tmp = st.nextToken();
       if(tmp.equals(from)) {
         bf.append(to);
       } else {
         bf.append(tmp);
       }
     }
     return bf.toString();
   }