To quote the guys... "patches are always welcome".
Glad you found a solution
Erick
On Mon, Feb 2, 2009 at 8:35 AM, ninaS <nina...@gmx.de> wrote:
>
> I already found another solution: I don't use a custom SortComparator.
> Another solution would be to define a default value for null.
>
> Would be nice if lucene in future would be able
> to search by null values also if a custom SortComparator is used.
>
> To tell you more:
>
> public class MyComparator extends SortComparator {
>
> ...
>
> public ScoreDocComparator newComparator (final IndexReader reader, final
> String fieldname)
> {
>
> throws IOException {
> final String field = fieldname.intern();
> final Comparable[] cachedValues
> = FieldCache.DEFAULT.getCustom (reader, field,
> CollatorBasedComparator.this);
>
> return new ScoreDocComparator() {
>
> public int compare (ScoreDoc i, ScoreDoc j) {
> ... // compare and handle nulls
> }
>
> public Comparable sortValue (ScoreDoc i) {
> return cachedValues[i.doc];
> }
>
> public int sortType(){
> return org.apache.lucene.search.SortField.CUSTOM;
> }
> };
>
> }
> @Override
> protected Comparable getComparable(String text) {
> return new MyComparable(text); //implements compare(Object
> a, Object b),
> handles nulls
> }
>
> }
>
> Using such a comparator will cause the exception above mentioned if null
> values appear in the sort field.
>
> That is because:
>
> FieldDocSortedHitQueue 163-166:
>
> case SortField.CUSTOM:{
> c = docA.fields[i].compareTo(docB.fields[i]);
> break;
> }
>
> does not check whether docA.fields[i] is null.
>
> As you see in line 134-148:
>
> case SortField.STRING:{
> String s1 = (String) docA.fields[i];
> String s2 = (String) docB.fields[i];
> // null values need to be sorted
> first, because of how
> FieldCache.getStringIndex()
> // works - in that routine, any
> documents without a value in the given
> field are
> // put first. If both are null, the
> next SortField is used
> if (s1 == null) c = (s2==null) ? 0 :
> -1;
> else if (s2 == null) c = 1; //
> else if (fields[i].getLocale() ==
> null) {
> c = s1.compareTo(s2);
> } else {
> c = collators[i].compare
> (s1, s2);
> }
> break;
> }
>
> nulls are handled with the type SortField.STRING.
>
> --
> View this message in context:
> http://www.nabble.com/NullPointerException-in-FieldDocSortedHitQueue.lessThan-with-custom-SortComparator-tp21702845p21789742.html
> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>
>
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