public abstract class FirstPassGroupingCollector<T> extends SimpleCollector
See org.apache.lucene.search.grouping
for more
details including a full code example.
Modifier and Type | Field and Description |
---|---|
protected TreeSet<CollectedSearchGroup<T>> |
orderedGroups |
Constructor and Description |
---|
FirstPassGroupingCollector(Sort groupSort,
int topNGroups)
Create the first pass collector.
|
Modifier and Type | Method and Description |
---|---|
void |
collect(int doc)
Called once for every document matching a query, with the unbased document
number.
|
protected abstract T |
copyDocGroupValue(T groupValue,
T reuse)
Returns a copy of the specified group value by creating a new instance and copying the value from the specified
groupValue in the new instance.
|
protected void |
doSetNextReader(LeafReaderContext readerContext)
This method is called before collecting
context . |
protected abstract T |
getDocGroupValue(int doc)
Returns the group value for the specified doc.
|
Collection<SearchGroup<T>> |
getTopGroups(int groupOffset,
boolean fillFields)
Returns top groups, starting from offset.
|
boolean |
needsScores()
Indicates if document scores are needed by this collector.
|
void |
setScorer(Scorer scorer)
Called before successive calls to
LeafCollector.collect(int) . |
getLeafCollector
protected TreeSet<CollectedSearchGroup<T>> orderedGroups
public FirstPassGroupingCollector(Sort groupSort, int topNGroups) throws IOException
groupSort
- The Sort
used to sort the
groups. The top sorted document within each group
according to groupSort, determines how that group
sorts against other groups. This must be non-null,
ie, if you want to groupSort by relevance use
Sort.RELEVANCE.topNGroups
- How many top groups to keep.IOException
- If I/O related errors occurpublic boolean needsScores()
Collector
true
if scores are needed.public Collection<SearchGroup<T>> getTopGroups(int groupOffset, boolean fillFields)
groupOffset
- The offset in the collected groupsfillFields
- Whether to fill to SearchGroup.sortValues
public void setScorer(Scorer scorer) throws IOException
LeafCollector
LeafCollector.collect(int)
. Implementations
that need the score of the current document (passed-in to
LeafCollector.collect(int)
), should save the passed-in Scorer and call
scorer.score() when needed.setScorer
in interface LeafCollector
setScorer
in class SimpleCollector
IOException
public void collect(int doc) throws IOException
LeafCollector
Note: The collection of the current segment can be terminated by throwing
a CollectionTerminatedException
. In this case, the last docs of the
current LeafReaderContext
will be skipped and IndexSearcher
will swallow the exception and continue collection with the next leaf.
Note: This is called in an inner search loop. For good search performance,
implementations of this method should not call IndexSearcher.doc(int)
or
IndexReader.document(int)
on every hit.
Doing so can slow searches by an order of magnitude or more.
collect
in interface LeafCollector
collect
in class SimpleCollector
IOException
protected void doSetNextReader(LeafReaderContext readerContext) throws IOException
SimpleCollector
context
.doSetNextReader
in class SimpleCollector
IOException
protected abstract T getDocGroupValue(int doc) throws IOException
doc
- The specified docIOException
protected abstract T copyDocGroupValue(T groupValue, T reuse)
groupValue
- The group value to copyreuse
- Optionally a reuse instance to prevent a new instance creation