Subject: Re: [Off Topic] Iterating through Parents/children help
From: "Matt Raible" <[EMAIL PROTECTED]>
===
Here's what I came up with using JSTL, but there's GOT to be a better
(recursive) way of doing this:
<c:forEach var="catalog" items="${myCatalog}">
<c:out value="${catalog.name}"/><br/>
<%-- Show all the items in this catalog --%>
<c:forEach var="link" items="${catalog.items}">
<c:out value="${link.name}"/>
</c:forEach>
<%-- show all the child catalogs for this catalog --%>
<c:forEach var="child1" items="${catalog.catalogs}">
<c:out value="${child1.name}"/>
<%-- Show all the items in this catalog --%>
<c:forEach var="link" items="${child1.items}">
<c:out value="${link.name}"/></a>
</c:forEach>
<%-- show all the child catalogs for this catalog --%>
<c:forEach var="child2" items="${child1.catalogs}">
<c:out value="${child2.name}"/>
<%-- Show all the library items in this catalog --%>
<c:forEach var="link" items="${child2.items}"
varStatus="status">
<c:out value="${link.name}"/>
</c:forEach>
<%-- show all the child catalogs for this catalog --%>
<c:forEach var="child3" items="${child2.catalogs}">
<c:out value="${child3.name}"/>
<%-- Show all the items in this catalog --%>
<c:forEach var="link" items="${child3.items}"
varStatus="status">
<c:out value="${link.name}"/>
</c:forEach>
</c:forEach>
</c:forEach>
</c:forEach>
</c:forEach>
"Matt Raible" <[EMAIL PROTECTED]> wrote in message
news:afquue$811$[EMAIL PROTECTED]...
> I have an difficult architecture problem. Please help if you can. Below
> are two tables that are linked by catalog_id.
>
> catalog
> --------------
> catalog_id
> catalog_name
> parent_id
>
> catalog_detail
> ---------------
> detail_id
> catalog_id
> detail_name
> detail_description
> detail_url
>
>
> So basically, these two tables are used to render the following in the
> "view"
>
> My First Catalog Entry
> -- URL to detail Entry
> -- URL to detail Entry
>
> My Second Catalog Entry
> -- URL to detail Entry
>
> ... you get the picture.
>
> My problem comes in in that a catalog entry can be a child of another
> catalog entry (not a detail entry). So you'd end up with something like
> this:
>
> My First Catalog Entry
> -- 1
> -- 2
> My Second Catalog Entry
> -- 3
> --
> My Third Catalog Entry....
>
> I need help with (1) How do I prepare this data for display on a page, and
> (2) How do I design my page without knowing how many levels deep to go?
>
> Here are my solutions to date:
>
> 1. I query the catalog table, and create an ArrayList of CatalogForm's
> (JavaBeans). As I'm adding a CatalogForm to the arraylist, I use the
> catalog_id to get the children of that catalog entry and set them as a
> Vector of DetailForm's on the CatalogForm. This works great without the
> parent concept. With the parent concept, maybe I should keep what I'm
> doing, but then lookup through the ArrayList and see if any CatalogForm's
> have parents. If so, set the CatalogForm as a ChildForm on it's parent.
>
> 2. Use JSTL and <c:forEach> to iterate through the catalogForm's and
> display the name and the detail's information. I can add a few more
> <c:forEach> tags, but this will only allow the architecture to traverse
the
> number of levels that I've defined in my JSP. Is there anyway to allow
for
> infinite levels? Maybe some sort of reflection - or even using XML and
XSL?
> Any and all ideas are welcome.
>
> Finally, I am only responsible for displaying this data, nothing has to be
> updated - that's up to another application that's already been written.
>
> Thanks,
>
> Matt
>
>
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