The problem is that Tapestry uses the usual Java String comparison for
sorting in Grid (generally speaking - Grid is not really localized).
String's compare uses the value of the character (and in UTF-8 encodings "b"
is greater than "G", as in ASCII).
So, if you want correct sorting you have to use a Collator.
Here's a correct GridDataSource (using a Collator on Strings):
/**
* {@link GridDataSource} for {@link Collection}s with correct {@link
String} sorting.
*/
@SuppressWarnings("unchecked")
public class MyCollectionGridDataSource implements GridDataSource
{
private final List list;
private final Locale locale;
private final Class<?> clazz;
/**
* Constructs a {@link GridDataSource} for the given collection (clazz
is
determined by first
* element in collection).
*
* @param collection the collection
* @param locale the current locale
*/
public MyCollectionGridDataSource(final Collection collection, final
Locale
locale)
{
this(collection, locale, null);
}
/**
* Constructs a {@link GridDataSource} for the given collection.
*
* @param collection the collection
* @param locale the current locale
* @param clazz which is the common super type of the objects in the
collection
*/
public MyCollectionGridDataSource(final Collection collection, final
Locale
locale, final Class<?> clazz)
{
Validate.notNull(collection, "collection");
if (collection instanceof List)
{
// Keep original list so that sorting it will reflect
changes in UI
list = (List) collection;
}
else
{
// Copy the collection so that we can sort it in a list
list = CollectionFactory.newList(collection);
}
this.locale = locale;
if (clazz != null)
{
this.clazz = clazz;
}
else
{
this.clazz = list.isEmpty() ? null :
list.get(0).getClass();
}
}
public int getAvailableRows()
{
return list.size();
}
public void prepare(int startIndex, int endIndex, List<SortConstraint>
sortConstraints)
{
for (final SortConstraint constraint : sortConstraints)
{
final ColumnSort sort = constraint.getColumnSort();
if (sort == ColumnSort.UNSORTED)
continue;
final PropertyConduit conduit =
constraint.getPropertyModel().getConduit();
final Comparator valueComparator = new Comparator<Comparable>()
{
public int compare(Comparable o1, Comparable o2)
{
// Simplify comparison, and handle case
where both are nulls.
if (o1 == o2)
return 0;
if (o2 == null)
return 1;
if (o1 == null)
return -1;
return (conduit.getPropertyType() ==
String.class) ?
Collator.getInstance(
locale).compare(o1, o2) :
o1.compareTo(o2);
}
};
final Comparator rowComparator = new Comparator()
{
public int compare(Object row1, Object row2)
{
int modifier = sort ==
ColumnSort.ASCENDING ? 1 : -1;
Comparable value1 = (Comparable)
conduit.get(row1);
Comparable value2 = (Comparable)
conduit.get(row2);
return modifier *
valueComparator.compare(value1, value2);
}
};
// We can freely sort this list because its just a copy.
Collections.sort(list, rowComparator);
}
}
/**
* Returns the type of the first element in the list, or null if the
list
is empty.
*/
public Class getRowType()
{
return clazz;
}
public Object getRowValue(int index)
{
return list.get(index);
}
}
You have to set the GridDataSource for your Grid or you add it to the
TypeCoercer.
--
Chris
darkslide wrote:
>
> Hi,
> could you please help me with sorting of lowercase and uppercase for Grid?
>
> Please see example:
>
> I have output grid as below:
>
> Name Description
>
> A ALPHA
> B beta
> C GAMA
>
> When I click on Description label and sort it descending then row number
> two will be as first :
>
> Name Description
>
> B beta
> C GAMA
> A ALPHA
>
> Could you please tell me why? And tell me how can I repair the bug?
>
> Thanks a lot for help
>
> BR
>
> Lukas Pavelka
>
--
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