Arrays in JSP form

[Juhan Voolaid]

Hi

I am looking for the best solution to my problem and I describe it with a small example.

I have a ArrayList of products:

class Products {
 private int id, price, quantity;
 private String name;
 ...
 setter and getter methods
}

And that ArrayList of products is sent to a form, where user can review the product list and change the quantity of each individual product. After submitting it, servlet takes over then.

Now the question is: how to construct that form, so that it is comfortable to access the data from servlet?

Here is one solution:

    
<form method="POST" action="<c:url value='chart.do'/>">
<table cellspacing="0" cellpadding="3">
<c:forEach var="item" items="${sessionScope.products}" varStatus="loopCount">
<tr>
<td>${loopCount.count}</td>
<td>${item.name}</td>
<td>${item.price}</td>
<td><input type="text" name="quantity_${loopCount.count}" value="${item.quantity}"/></td>
</tr>
 <input type="hidden" name="id_${loopCount.count}" value="${item.id}"/> 
 <input type="hidden" name="price_${loopCount.count}" value="${item.price}"/>
</c:forEach>
</table>
<input type="submit" name="submit" value="submit"/>

And in this case it is not so easy to get the parameters in servlet. When the data is like so:
id_1=2; price_1=200; quantity_1=3;
id_2=16; price_2=300; quantity_2=1;
id_3=7; price_3=50; quantity_3=5;
....
So in servlet I have to check when the ${loopCount.count} stopped by compareing if request.getParameter("id_3")==null

But I am woundering, if there is more better solution for that type of problem. In my mind I am thinking of presenting and getting back arrays from html form somehow, but I don't know if it is possible.


Thanx.

[Juhan Voolaid]

And another thing (even though it gous to struts subject): how to make a ActionForm to validate this generated form, because I don't know how many "quantity_x" parameters there will be?

[Stefan Evans]

Yes there is a better way.
Struts "indexed properties"

http://struts.apache.org/struts-doc-1.2.8/userGuide/building_view.html#indexed
http://struts.apache.org/struts-doc-1.2.8/faqs/indexedprops.html