Struts logic:iterate on multiple collections

Your solution requires JSP scriplet code. I need to do it using the Struts taglib. Struts removes all scriplet code from the JSP and conforms to the MVC architecture.

> Struts removes all scriplet code from the JSP

not afaik

Try using indexId:
<logic:iterate id="products" indexId="i" name="displayProductsForm" property="productId" scope="session">
then use index to extract element from second collection.

> Struts removes all scriplet code from the JSP

I meant to say Struts removes the need for scriptlet code in the JSP, not that it literally deletes any code.

Doesn't really remove the need, it provides you with a set of higher level constructs to use. Thus limiting available functionality effectively, requireing you to still use scriptlets if tags don't provide the functionaslity you require.

Did indexId help u solve your problem?

> I meant to say Struts removes the need for scriptlet code in the JSP

As objects said, not 100%

I didn't have much luck with indexId.

I ran across this code which appears to do just what I want - accessing two Collections (ArrayList productId, productName) within a single iteration loop:

<logic:iterate id="products" name="productsForm">
  <TD><bean:write name="products" property="productId" /></TD>
  <TD><bean:write name="products" property="productName" /></TD>          
</logic:iterate>

I'm assuming there is a Bean named ProductsForm.class. What is the relevance of the 'id' parameter? Is is just a local variable for the use of bean:write, or is it a Bean that feeds individual Collection elements to this page?

I'm also assuming a struts-config.xml entry as follows:

  <form-beans>
     <form-bean     name="productsForm"
                    type="com.bnb.ProductsForm"/>
  </form-beans>

  <action-mappings>
       <action
            path="/displayProducts"
            type="com.bnb.ProductsAction"
            name="productsForm"
            input="/pages/error.jsp"
            scope="session">
            <forward name="success" path="/pages/productSummary/productsDisplay.jsp" />
            <forward name="failure" path="/pages/error.jsp" />
      </action>
  </action-mappings>

How far off-base am I?

> accessing two Collections (ArrayList productId, productName) within a single iteration loop:

Thats not what that code does. It is iterating over *one* list, and accessing two *properties for the elements.

> What is the relevance of the 'id' parameter?

It's the name of the variable used to hold the list elemement.

you can only iterate over one list using the iterate tag. What you need to do is use the index of each element to retrieve the corresponding element from the other list inside your loop.

Back to using indexed properties, the following code snippet:

<logic:iterate id="products" indexId = "i" name="productsForm" property="productId" >          
   <LI><a href="http://www.bnb.com/myProg.cgi?p_id=<bean:write name="products"
          property="productId[i]" filter="true" />"> <bean:write name="products"
          property="sizes[i]" filter="true"/></a>
   </LI>
</logic:iterate>

...results in:

java.lang.IllegalArgumentException: Invalid indexed property 'productId[i]'

The ActionForm includes:

...
      private ArrayList productId;
      private ArrayList sizes;
...
      public String getProductId(int i) {
            return (String)(productId.get(i));
      }

      public String getSizes(int i) {
            return (String)(sizes.get(i));
      }
...

Take a step back, can you post the code you use to access *just* product id.
We can then modify that to also show size.

OK. This code works insofar as it properly iterates over the productIds and inserts them properly into the JSP:

<logic:iterate id="products" name="productsForm" property="productId" >          
    <LI><a href="http://www.bnb.com/myProg.cgi?p_id=<bean:write name="products" filter="true" />">size</a>
    </LI>
</logic:iterate>

ActionForm code:

private ArrayList productId;

public ArrayList getProductId() {
      return productId;
}

try something like:

<logic:iterate id="products" name="productsForm" indexId="i" property="productId" >          
    <LI><a href="http://www.bnb.com/myProg.cgi?p_id=<bean:write name="products" filter="true" />"><%= productsForm.getSizes(i) %></a>
    </LI>
</logic:iterate>

The code you suggested results in the following compile error:

org.apache.jasper.JasperException: Unable to compile class for JSP

cannot resolve symbol
symbol  : variable productsForm  
location: class org.apache.jsp.pages.productSummary.productsDisplay_jsp
          out.print( productsForm.getSizes(i) );
                     ^

'productsForm' is the Bean name referenced in the struts-config.xml file (see above.)

I then tried changing 'productsForm' (the Bean name) to ProductsForm (the Bean class) - no luck.

I then added a 'jsp:useBean' statement - still, no luck.

Of interest:

<bean:write name="productsForm" property="sizes(i)" filter="true" />

...does not result in a compile error. It doesn't return anything, but at least it compiles. (A small step forward!?!?)

sorry, should be read as:
you CANNOT avoid using index and thus you cannot avoid using scriptlet

Agreed! This is much more elegant than using indexes - with the added benefit that it works; albeit with a little more coding effort in the ActionForm (where it belongs.)

Thanks!

glad that it works for you! It's my pleasure to help :-)