Actually that didn't work out when I tested it.
A TreeMap sorts elements by calling Object.equals. When it encounters my
null element, it tries to de-reference it and throws an exception.
HashMap does not produce any exceptions, but leaves my numbers in a very
strange order like:
3, 2, 4, 1, 5, 0
even though I inserted them in order.
In summary, I am still trying to have a list of numbers which also allows
null to be available through my user interface's select dropdown box.
Ideally I would like to use an ArrayList if I could resolve the freemarker
exception.
Thanks again,
David
DavidCAIT wrote:
>
> I did find a workaround which is a bit undesirable.
>
> If I change my ArrayList to a TreeMap and store the same value for the key
> and the value then the problem disappears. However, it is a bit wasteful
> to store each value in the list twice.
>
> Any other ideas? If not, my workaround is good enough for me.............
>
>
> DavidCAIT wrote:
>>
>> Hi,
>>
>> I have a list of Integers and I want one of the options to be null (since
>> it is a search field). However, I get the following freemarker exception
>> when rendering my JSP:
>>
>>>> FreeMarker template error!
>>
>>>> Error on line 73, column 13 in template/simple/select.ftl
>>>> stack.findValue('top') is undefined.
>>>> It cannot be assigned to itemKey
>>>> The problematic instruction:
>>>> ----------
>>>>==> assignment: itemKey=stack.findValue('top') [on line 73, column 13
in template/simple/select.ftl]
>>>> in user-directive s.iterator [on line 63, column 1 in
>>>> template/simple/select.ftl]
>>>> ----------
>>
>> I am using Struts 2.0.11 with the following action:
>>
>> public class simpleAction implements Preparable {
>>
>> // both myList and value have a public getter and setter
>> private List<Integer> myList = new ArrayList<Integer>();
>> private Integer value;
>>
>> public String prepare() {
>>
>> myList.add(null); // commenting out this line removes the runtime JSP
>> exception
>> for (int i = 0; i < 60; i++) {
>> myList.add(i);
>> } } }
>>
>> My JSP page:
>>
>> <html>
>> <body>
>> <s:form action="anotherAction">
>> <s:select list="myList" />
>> <s:submit />
>> </s:form>
>> </body></html>
>>
>> Does anyone have any ideas or workarounds about how I can include a null
>> entry in a list of integers without getting this freemarker exception?
>> Thanks,
>>
>> David
>>
>
>
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