Error while accessing collections

[arshad_nj]

This is an intermittent problem for the same record set, here is the error I am getting:

org.springframework.beans.InvalidPropertyException: Invalid 
property 'alternateResources[0]' of bean class [xxx.vo.ScreenProposalMaterialVO]: 
Index of out of bounds in property path 'alternateResources[0]'; nested exception is 
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
	at java.util.ArrayList.RangeCheck(ArrayList.java:546)
	at java.util.ArrayList.get(ArrayList.java:321)
	at org.springframework.beans.BeanWrapperImpl.getPropertyValue
(BeanWrapperImpl.java:408)
	at org.springframework.beans.BeanWrapperImpl.getNestedBeanWrapper(BeanWrapperImpl.java:297)
	at org.springframework.beans.BeanWrapperImpl.getBeanWrapperForPropertyPath(BeanWrapperImpl.java:274)

and below is code which is causing this:

<c:forEach var="resourceEntry" 
items="${command.alternateResources}"
varStatus="lineInfo">
.....................
<spring:bind path="command.alternateResources[${lineInfo.index}].price">
....................

Any ideas? If the collection is empty, it should go into foreach block only but from the debugging it is clear that the collection is having its associated values but it fails when it encounters the spring bind.

[arshad_nj]

Just to make sure it is not a JSTL issue, I did added additional test though it is not required:
<c:if test="${not empty command.alternateResources}">
before the foreach.

Again, as I said, it is intermittent, we get this once in a while.

Your help is highly appreciated.

Thanks,
Arshad

[arshad_nj]

Here is what we followed:
http://opensource.atlassian.com/proj.../browse/SPR-52

and the example is:

<c:forEach items="${person.addresses}" var="address" varStatus="loopStatus">

<spring:bind path="person.addresses[${loopStatus.index}].street">
Street: <input type="text" name="<%= status.getExpression() %>" value="<%= status.getDisplayValue() %>">
</spring:bind>
<p>

<spring:bind path="person.addresses[${loopStatus.index}].zip">
Zip: <input type="text" name="<%= status.getExpression() %>" value="<%= status.getValue() %>">
</spring:bind>
<p>

</c:forEach>

and the code is from Juergen Hoeller who is spring team member I belive. What I can say is the code is correct syntactical from spring point of view but gives errors intermittently at runtime

Thanks,
Arshad

[Jörg Heinicke]

Is this still the actual situation? It's absolutely awkward to use and understand. Furthermore it does not work with non-indexed collections. Why must <spring:bind> always traverse from the command object (absolute context) and does not allow a relative context? So in a loop it would be easily possible to set that context and <spring:bind> would use that one:

<c:forEach items="${collection}" var="collEntry">
  <spring:newPath path="collEntry">
    <tr>
      <td>
        <spring:bind path="collEntry.key">${status.value}</spring:bind>
      </td>
      <td>
        <spring:bind path="collEntry.value">${status.value}</spring:bind>
      </td>
    </tr>
  </spring:newPath>
</c:forEach>

This would make it usable for non-indexed collections and more readable and less error-prone in general. It would not break the default concept of <c:forEach> and match similar concepts in XSLT (or XML/XPath in general).

Jörg

[Jörg Heinicke]

For the records: I added a Jira enhancement request for it.

Jörg