INTERACTIVE WEB SERVICES WITH JAVA

No Need to Program?

- the tag library approach goes to great length to avoid (blatant) programming.

Part of the philosophy behind JSP(/ASP/PHP) is:

anyone can write HTML documents
Web services shouldn't be any harder
programming is not necessary
just choose the desired behavior from a tag library

This quickly breaks down:

new behavior requires ever more tag libraries
Java details creep in anyway

The tag code:

<c:forEach var="item" items="$session:cart.items"> ... <tr> <td align="right" bgcolor="#ffffff"> <c:expr value="$item.quantity"/> </td> ... </c:forEach>

abbreviates the JSP code:

<% Iterator i = cart.getItems().iterator(); while (i.hasNext()) { ShoppingCartItem item = (ShoppingCartItem)i.next(); ... %> <tr> <td align="right" bgcolor="#ffffff"> <%=item.getQuantity()%> </td> ... <% } %>

This only works under a lot of assumptions:

the cart implements a getItems() method
getItems() returns an object that implements an iterator() method
a ShoppingCartItem implements a getQuantity()method

Debugging rapidly becomes a pain...