Re: Using Variable as a List name

Thursday, October 8, 2009, 6:50:14 AM, rizzz86 wrote:

> What I want to say is that, "argList1" contains the menu names:
>
> List argList1 = new ArrayList();
> argList1.add(menu1);
> argList1.add(menu2);

So, menu1 and menu2 are String-s.

> And "argList2, argList3" contains the subMenus of "menu1, menu2"
> respectively. (This will be done while populating "argList1") It will look
> like as follows:
>
> // subMenus of menu1
> List argList2 = new ArrayList();
> argList2.add(subMenu1);
> argList2.add(subMenu2);
> argList2.add(subMenu3);
>
> // subMenus of menu2
> List argList3 = new ArrayList();
> argList3.add(subMenu4);
> argList3.add(subMenu5);
> argList3.add(subMenu6);
>
> I am passing HashMap "root" as the argument for by freemarker template by
> setting "argList1, menu1, menu2" keys.
>
> HashMap root = new HashMap();
> root.put("argList1",argList1);
> root.put("menu1",argList2);
> root.put("menu2",argList3);

I assume argLits1 contains the list of strings: "menu1", "menu2"

> Now the .ftl have an outer loop for "argList1" (for main menus) and inner
> loop (for their subMenus). Another thing is that I doesn't know the the menu
> names (i.e. menu1, menu2) while rendering my subMenus.

Why not? It's in the loop variable of the outer loop, isn't it?

> I have to get these menu names from the "argList1" and use them as a
> list to access "root.put("menu1",argList2) or
> root.put("menu2",argList3)"
>
> Doing this <#foreach subMenu in .vars[menu]> gives the following Error
> "freemarker.core.InvalidReferenceException: Expression .vars[menu] is
> undefined"

Well, what's the value of the "menu" variable? If it's the String
"menu1" or "menu2", and you have such top-level variables (as you put
the into the root above), it must work.

> OR can someone suggest a better way to render these subMenus.

If there is a problem here, then is not with the rendering, but with
the odd data structure you are using. Since the menu system is
hierarchical, the data-structure should be too. I would create a
MenuItem class that is a JavaBean, and has a "title" and "submenus"
property, last being a List<MenuItem>. Then I don't have to type the
titles twice just to associate menu items with submenus (and thus
potential making a mistake), traversal would be trivial, and I can
easily associated other properties to MenuItems later (like icon,
action, etc.).

> I also cannot able to use 2D Arrays in ftl's.

Why not? It should work.

> rizzz86
>
>
>
>
> rizzz86 wrote:
>> 
>> Hi all,
>> 
>> I am trying to use any variable as a name of list ... i.e.,
>> 
>> <#foreach list1 in argList1>
>>      <#foreach list2 in list1> 
>>                      // The name of list2 is the first element of list1
>>      </#foreach>
>> </#foreach>
>> 
>> Following error occured if I pass variable as a list name "Expected
>> collection or sequence. list1 evaluated instead to
>> freemarker.ext.beans.StringModel"
>> 
>> Can anyone help ?
>> 
>> rizzz86

-- 
Best regards,
 Daniel Dekany


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