includeProperties Does Not Work with a List of Lists

I found this issue when using server-side processing with JQuery Datatables and attempting to populate.

Say I have this getter/field on my action:

public List<List<String>> getListOfLists() {
	return listOfLists;
}

My struts.xml is defined as follows:

<action name="GetData" method="loadData"
class="com.example.web.action.WebAction">
	<result type="json" >
		<param name="ignoreHierarchy">false</param>
		<param name="includeProperties">listOfLists\[\d+\]\[\d+\]</param>
	</result>
</action>

However, the include patterns that are constructed within JSONUtil are not accurate. Instead of making the expected pattern that would work:

listOfLists
listOfLists\[\d+\]
listOfLists\[\d+\]\[\d+\]

Only the following are created:

listOfLists\[\d+\]
listOfLists\[\d+\]\[\d+\]

Because the first "listOfLists" is not created, the property is excluded in the results.

This all happens because of line 463 in JSONUtil:

addPattern(results, patternExpr.substring(0, patternExpr.lastIndexOf(includePatternData.get(ARRAY_BEGIN_STRING).get(type))), type);

Since we're going at the last index of the ARRAY_BEGIN_STRING string, it's skipping the first index. This could be updated to be smarter to build the include patterns as expected.