Thanks for pondering the question James.
Yes, when I say "commit" I mean "ec.saveChanges()".
We have a listController that manages an array of enterprise objects that
have been fetched from the database. "displayedObjects" is just a mutable
clone of that array that is sorted and filtered before being presented to
the user.
If I simply uncomment the line for "setSupportForClass()" then the problem
dissappears. There is no issue with commits, etc. So the problem must be:
1) "CXNullsAtEndComparisonSupport" has a bug that we just haven't been
able to see yet. Perhaps in the way that it extends Apple's class and the
subtleties of polymorphic / non-polymorphic behavior when static methods
are involved.
2) "setSupportForClass()" is being called incorrectly. Maybe I can't give
it "Object.class" as a parameter for some strange reason. In other words,
perhaps sometimes it uses my support class and other times it uses the
default support class which confuses the K2Sort algorithm and leaves it in
an unworkable state.
-- Aaron
James Cicenia <[EMAIL PROTECTED]> wrote on 31-01-2008 02:48:26 PM:
> Aaron -
>
> I really don't know. I have created my own specific comparators that
> worked... and I don't see anything in your
> ComparisonSupport class that should stop working upon a commit.
>
> When you say commit do you mean save changes? Are you getting a
> fresh array for displayedObjects?
>
> - James
>
> On Jan 31, 2008, at 1:26 PM, [EMAIL PROTECTED] wrote:
>
>
> Hi James,
>
> The ComparisonSupport becomes transparent and used universally
> throughout the app. Here's an excerpt of one place where a sort occurs:
>
> NSMutableArray displayedObjects = <the objects to display in a
> paginated list on the screen>
> NSMutableArray sortOrderings = <a list of EOSortOrdering objects
> taking a key and an NSSelector>
> EOSortOrdering.sortArrayUsingKeyOrderArray(displayedObjects,
sortOrderings);
>
> This is often called by clicking a little toggle icon to modify the
> "sortOrderings" array with a particular "key" and either
> "compareAscending" or "compareDescending".
>
> It works like a charm. The null values are placed at the very end of
> an ascending sort and placed at the beginning of a descending sort.
> It works so long as we haven't done any commits to the database.
> Sounds odd, I know, because I don't fully understand what is
> happening. It probably isn't the commit to the database itself but
> some other nuance. All I know with certainty is that I can move
> around the whole app and happily re-sort columns anywhere but as
> soon as I do a commit I'm no longer able to reliably sort columns on
> any page. Also, once it gets in this bad state, any new wosessions I
> start exhibit the same problem immediately.
>
> -- Aaron
>
> James Cicenia <[EMAIL PROTECTED]> wrote on 31-01-2008 02:01:03 PM:
>
> > What do you mean it no longer works after commits?
> >
> > How are you using your comparator?
> >
> > -James Cicenia
> >
> > On Jan 31, 2008, at 12:34 PM, [EMAIL PROTECTED] wrote:
> >
> >
> > What happens when you want to sort ten values in ascending order but
> > one of them is null? Does that void value get put at the beginning,
> > the middle, or the end?
> >
> > Apple decided that null values (or keyPaths that return a null
> > value) should be placed at the beginning of an array sorted in
> > ascending order. Perhaps they felt that "null is less than zero".
> >
> > For us, it seems that null values should be placed at the end of an
> > ascending sort. More often than not, null values make more sense to
> > be placed at the end of the list when working in our Domain.
> >
> > Has anyone crossed this bridge before?
> >
> > We've tried our hand at a solution which is listed at the bottom of
> > this message. It works so long as no commits have been made to the
> > database! After a commit, from any page in the app, sorting no
> > longer works as expected and often results in a K2Sort error.
It'sbaffling.
> >
> > Our class extends the default sorting logic of EOSortOrdering.
> > ComparisonSupport (the class that does sorting globally for WO). We
> > really only want to override "handleNulls()" but because it is both
> > private and static, we need to redo a few other methods as well.
> > Functionally, our class is identical but choose to place null values
> > at the end of the list for an ascending sort.
> >
> > Here is the line we add to the Appliction's constructor to get the
> > ball rolling globally:
> > ==========================
> >
> > EOSortOrdering.ComparisonSupport.setSupportForClass(new
> > CXNullsAtEndComparisonSupport(), Object.class);
> >
> >
> > Here is the source code to the custom ComparisonSupport:
> > ==========================
> >
> > public class CXNullsAtEndComparisonSupport extends EOSortOrdering.
> > ComparisonSupport {
> >
> > public static final Logger _logger = Logger.
> > getLogger(CXNullsAtEndComparisonSupport.class);
> >
> > public CXNullsAtEndComparisonSupport() {}
> >
> > protected static final int kNeitherNull = -42;
> >
> > protected static int handleNulls(Object left, Object right)
> > {
> > if(left == null || left == NSKeyValueCoding.NullValue)
> > return right != null && right !=
> > NSKeyValueCoding.NullValue ? NSComparator.OrderedDescending :
> > NSComparator.OrderedSame;
> > return right != null && right != NSKeyValueCoding.
> > NullValue ? kNeitherNull : NSComparator.OrderedAscending;
> > }
> >
> > private static final NSTimestampFormatter
> > defaultStringTimestampFormatter = new NSTimestampFormatter("%Y-%m-%d
> > %H:%M:%S %Z");
> >
> > protected static NSTimestamp coerceToTimestampClass(Object
value)
> > {
> > if(value instanceof NSTimestamp)
> > return (NSTimestamp)value;
> > if(value instanceof Date)
> > return new
NSTimestamp(((Date)value).getTime());
> > if(value instanceof Number)
> > return new NSTimestamp(((Number)value).
> longValue());
> > try {
> > return (NSTimestamp)
> > defaultStringTimestampFormatter.parseObject((String)value);
> > } catch (Exception e) {
> > //fixme: do something more.
> > _logger.info("coerceToTimestampClass failed.
> > Message = " + e.getMessage());
> > return null;
> > }
> > }
> >
> > protected int _genericCompareTo(Object left, Object right)
> > {
> > int nullCheck = handleNulls(left, right);
> > if(nullCheck != kNeitherNull) {
> > return nullCheck;
> > }
> > Class LHSClass = left.getClass();
> > if(LHSClass == _NSUtilities._StringClass)
> > return
left.toString().compareTo(right.toString());
> > if((left instanceof Number) || LHSClass ==
> > _NSUtilities._BooleanClass)
> > return _NSUtilities.
> > compareNumbersOrBooleans(left, right);
> > if(left instanceof Date)
> > {
> > if(LHSClass != NSTimestamp._CLASS)
> > left = coerceToTimestampClass(left);
> > right = coerceToTimestampClass(right);
> > }
> > if(left instanceof Comparable)
> > return ((Comparable)left).compareTo(right);
> > else
> > return
left.toString().compareTo(right.toString());
> > }
> >
> > protected int _genericCaseInsensitiveCompareTo(Object left,
> > Object right)
> > {
> > int nullCheck = handleNulls(left, right);
> > if(nullCheck != kNeitherNull)
> > return nullCheck;
> > Class LHSClass = left.getClass();
> > if(LHSClass == _NSUtilities._StringClass)
> > return left.toString().
> > compareToIgnoreCase(right.toString());
> > if((left instanceof Number) || LHSClass ==
> > _NSUtilities._BooleanClass)
> > return _NSUtilities.
> > compareNumbersOrBooleans(left, right);
> > if(left instanceof Date)
> > {
> > if(LHSClass != NSTimestamp._CLASS)
> > left = coerceToTimestampClass(left);
> > right = coerceToTimestampClass(right);
> > return ((Comparable)left).compareTo(right);
> > } else
> > {
> > return left.toString().
> > compareToIgnoreCase(right.toString());
> > }
> > }
> >
> > } _______________________________________________
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