[FLEX-22452] Error in SortField.nullCompare logic

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Adobe Flex SDK 3.2 (Release)
• Fix Version/s: Apache Flex 4.9.0
• Component/s: mx: General, Runtime Exceptions
• Labels: easyfix easytest
• Environment: Affected OS(s): All OS Platforms; Affected OS(s): All OS Platforms; Browser: Firefox 3.x; Language Found: English
• Assignee: Justin Mclean
• Reporter: Adobe JIRA
• Created: 15/Dec/09 10:01
• Updated: 17/Apr/13 08:54
• Resolved: 17/Apr/13 08:53

Description

Steps to reproduce:
1. Populate an AdvancedDataGrid with multiple columns, one of which is a "Number" type
2. Have some of the Numbers be null and some be values
3. Sort on this column will crash with exception below

Actual Results:
Error: Cannot determine comparator for SortField with name 'policy_score'.
at mx.collections::SortField/nullCompare()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\SortField.as:566]
at mx.collections::SortField/http://www.adobe.com/2006/flex/mx/internal::internalCompare()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\SortField.as:234]
at mx.collections::Sort/internalCompare()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\Sort.as:831]
at mx.collections::Sort/findItem()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\Sort.as:528]
at mx.collections::ListCollectionView/getItemIndex()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:513]
at ListCollectionViewCursor/collectionEventHandler()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:2154]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::ListCollectionView/dispatchEvent()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:833]
at mx.collections::ListCollectionView/internalRefresh()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1275]
at mx.collections::ListCollectionView/refresh()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:402]
at mx.controls::AdvancedDataGridBaseEx/sortHandler()[C:\work\flex\dmv_automation\projects\datavisualisation\src\mx\controls\AdvancedDataGridBaseEx.as:6864]
at mx.controls::AdvancedDataGrid/sortHandler()[C:\work\flex\dmv_automation\projects\datavisualisation\src\mx\controls\AdvancedDataGrid.as:6896]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.core::UIComponent/dispatchEvent()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\UIComponent.as:9298]
at mx.controls::AdvancedDataGrid/headerReleaseHandler()[C:\work\flex\dmv_automation\projects\datavisualisation\src\mx\controls\AdvancedDataGrid.as:7117]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.core::UIComponent/dispatchEvent()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\UIComponent.as:9298]
at mx.controls::AdvancedDataGridBaseEx/mouseUpHandler()[C:\work\flex\dmv_automation\projects\datavisualisation\src\mx\controls\AdvancedDataGridBaseEx.as:5733]
at mx.controls::AdvancedDataGrid/mouseUpHandler()[C:\work\flex\dmv_automation\projects\datavisualisation\src\mx\controls\AdvancedDataGrid.as:8454]

Expected Results:

• Problem is that nullCompare checks attempts to get value for attribute for each row being compared. If one of the rows returns a null value the the entire row is used as the value. Rather, a null value should be treated either as the "lowest" value or the "highest" value for the purpose of numeric comparsions thereby pushing all nulls to the top or bottom of the list. (I would suggest lowest)

Workaround (if any):

• write your own custom sort routine