Re: A custom way to sort EOs by key ?
Re: A custom way to sort EOs by key ?
- Subject: Re: A custom way to sort EOs by key ?
- From: Mike Schrag <email@hidden>
- Date: Fri, 11 May 2007 16:06:17 -0400
or (untested ... syntactically correct is all i can vouch for here):
public class CompositeComparator extends NSComparator {
private NSComparator[] _comparators;
public CompositeComparator(NSComparator... comparators) {
_comparators = comparators;
}
@Override
public int compare(Object object1, Object object2) throws
ComparisonException {
int result = NSComparator.OrderedSame;
for (NSComparator comparator : _comparators) {
result = comparator.compare(object1, object2);
if (result != NSComparator.OrderedSame) {
break;
}
}
return result;
}
}
On May 11, 2007, at 3:52 PM, Chuck Hill wrote:
On May 11, 2007, at 12:55 AM, Fabrice Pipart wrote:
On May 10, 2007, at 11:19 PM, Matthew W. Taylor wrote:
It sounds like what you want to do is perform "Natural" sort
ordering to the results.
sortedArray = unsortedArray.sortedArrayUsingComparator(new
EOCustomObjectNaturalOrderComparator("nameOfKeyToSortBy"));
// EOCustomObjectNaturalOrderComparator.java
That's absolutely what I was looking for :-)
I had just missed the NSArray.sortedArrayUsingComparator method :(
And it's far more obvious how to subclass a NSComparator than a
NSSelector ;-)
The only drawback compared to
EOSortOrdering.sortedArrayUsingKeyOrderArray is that I cannot do
ordering for several keys : ORDER BY name, otherKey ...
Absolutely you can sort by multiple keys! Here is how to do it:
/**
* NSComparator to sort on Zone, Production Status, and Product
Type. This relies on the Any status/type
* having a value of 0 so that more general associations sort
later in the list. The more specific ones
* earlier in the list have a higher priority.
*/
public static class TypeStatusComparator extends NSComparator
{
public int compare(Object object1, Object object2) throws
NSComparator.ComparisonException
{
int result =
NSComparator.AscendingNumberComparator.compare(((ColorSwatchZone)
object1).zone().zoneID(),
((ColorSwatchZone)object2).zone().zoneID());
if (result == NSComparator.OrderedSame)
{
result =
NSComparator.DescendingNumberComparator.compare(((ColorSwatchZone)
object1).productionStatus(),
((ColorSwatchZone)object2).productionStatus());
}
if (result == NSComparator.OrderedSame)
{
result =
NSComparator.DescendingNumberComparator.compare(((ColorSwatchZone)
object1).productType(),
((ColorSwatchZone)object2).productType());
}
return result;
}
}
Chuck
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Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
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