10.4.2 Printing the shopping cart with IterateTag
All of the scriptlets in listing 10. 13 can be eliminated by making use of our new IterateTag
as in listing 10.14. Executing the JSP code on a sample cart content
yielded the response presented in figure 10.2.
Listing 10.14 JSP file that uses custom tags to present the cart information
<%@ page errorPage="error.jsp" %>
<%@ taglib
uri=" http://www.manning.com/jsptagsbook/iteration-taglib" 
prefix=" iter" %>
<%@ taglib
uri=" http://www.manning.com/jsptagsbook/conditions-taglib"
prefix=" cond" %>
<%@ taglib
uri=" http://www.manning.com/jsptagsbook/beans-taglib"
prefix=" bean" %>
<html>
<body>
<cond: with name=" cart" property="empty">
<cond: test condition="eq true">
Your cart is empty.
</cond:test>
<cond: test condition="eq false">
Your cart contains the following products:
<table>
<tr>< th> Product</th> <th> Quantity</th> <th> Price</th> </tr>
<iter:iterate name="cart" property="products" id="product"> 
<tr>
<td>< bean: show name="product" property="name"/> </td>
<td>< bean: show name="product" property="quantity"/></td> 
<td>< bean: show name="product" property="dollars"/>.
<bean: show name="product"property=" cents"/>$</td>
</tr>
</iter:iterate>
<tr>
<td> Totals< td>
<td>< bean:show name="cart" property="dollars"/>. 
<bean:show name="cart" property="cents"/>$< td>
<tr>
</table>
</cond:test>
</cond:with>
</body>
</html>
References all the TLDs we use.
Enumerates the products (using the enumeration property).
Presents the product's properties.
Presents the total price (property of the cart).
Comparing listings 10.13 and 10.14 shows the advantages of using custom tags.
Listing 10. 14 is much simpler: all the curly brackets, type casting, and the like are
gone, and it is readable by almost anyone. Moreover, all tag supporting tools can
manipulate the file and we feel certain that they will be able to get along with our
custom tags. Listing 10.13 is littered with endless scriptlets to the point that developing
the page without a programmer's help is very difficult. Which page would
you prefer to have your HTML coder maintain?
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