public abstract class AbstractFirstPassGroupingCollector<GROUP_VALUE_TYPE> extends Collector
See org.apache.lucene.search.grouping
for more
details including a full code example.
Modifier and Type | Field and Description |
---|---|
protected TreeSet<CollectedSearchGroup<GROUP_VALUE_TYPE>> |
orderedGroups |
Constructor and Description |
---|
AbstractFirstPassGroupingCollector(Sort groupSort,
int topNGroups)
Create the first pass collector.
|
Modifier and Type | Method and Description |
---|---|
boolean |
acceptsDocsOutOfOrder()
Return
true if this collector does not
require the matching docIDs to be delivered in int sort
order (smallest to largest) to Collector.collect(int) . |
void |
collect(int doc)
Called once for every document matching a query, with the unbased document
number.
|
protected abstract GROUP_VALUE_TYPE |
copyDocGroupValue(GROUP_VALUE_TYPE groupValue,
GROUP_VALUE_TYPE 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 abstract GROUP_VALUE_TYPE |
getDocGroupValue(int doc)
Returns the group value for the specified doc.
|
Collection<SearchGroup<GROUP_VALUE_TYPE>> |
getTopGroups(int groupOffset,
boolean fillFields)
Returns top groups, starting from offset.
|
void |
setNextReader(AtomicReaderContext readerContext)
Called before collecting from each
AtomicReaderContext . |
void |
setScorer(Scorer scorer)
Called before successive calls to
Collector.collect(int) . |
protected TreeSet<CollectedSearchGroup<GROUP_VALUE_TYPE>> orderedGroups
public AbstractFirstPassGroupingCollector(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 Collection<SearchGroup<GROUP_VALUE_TYPE>> 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
Collector
Collector.collect(int)
. Implementations
that need the score of the current document (passed-in to
Collector.collect(int)
), should save the passed-in Scorer and call
scorer.score() when needed.setScorer
in class Collector
IOException
public void collect(int doc) throws IOException
Collector
Note: The collection of the current segment can be terminated by throwing
a CollectionTerminatedException
. In this case, the last docs of the
current AtomicReaderContext
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 class Collector
IOException
public boolean acceptsDocsOutOfOrder()
Collector
true
if this collector does not
require the matching docIDs to be delivered in int sort
order (smallest to largest) to Collector.collect(int)
.
Most Lucene Query implementations will visit
matching docIDs in order. However, some queries
(currently limited to certain cases of BooleanQuery
) can achieve faster searching if the
Collector
allows them to deliver the
docIDs out of order.
Many collectors don't mind getting docIDs out of
order, so it's important to return true
here.
acceptsDocsOutOfOrder
in class Collector
public void setNextReader(AtomicReaderContext readerContext) throws IOException
Collector
AtomicReaderContext
. All doc ids in
Collector.collect(int)
will correspond to IndexReaderContext.reader()
.
Add AtomicReaderContext.docBase
to the current IndexReaderContext.reader()
's
internal document id to re-base ids in Collector.collect(int)
.setNextReader
in class Collector
readerContext
- next atomic reader contextIOException
protected abstract GROUP_VALUE_TYPE getDocGroupValue(int doc)
doc
- The specified docprotected abstract GROUP_VALUE_TYPE copyDocGroupValue(GROUP_VALUE_TYPE groupValue, GROUP_VALUE_TYPE reuse)
groupValue
- The group value to copyreuse
- Optionally a reuse instance to prevent a new instance creationCopyright © 2000-2015 The Apache Software Foundation. All Rights Reserved.