Class MultiCollector
Collector
which allows running a search with several
Collector
s. It offers a static wrap(org.apache.lucene.search.Collector...)
method which accepts a
list of collectors and wraps them with MultiCollector
, while
filtering out the null
null ones.-
Method Summary
Modifier and TypeMethodDescriptionboolean
Returntrue
if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) toCollector.collect(int)
.void
collect
(int doc) Called once for every document matching a query, with the unbased document number.void
setNextReader
(AtomicReaderContext context) Called before collecting from eachAtomicReaderContext
.void
Called before successive calls toCollector.collect(int)
.static Collector
Wraps a list ofCollector
s with aMultiCollector
.
-
Method Details
-
wrap
Wraps a list ofCollector
s with aMultiCollector
. This method works as follows:- Filters out the
null
collectors, so they are not used during search time. - If the input contains 1 real collector (i.e. non-
null
), it is returned. - Otherwise the method returns a
MultiCollector
which wraps the non-null
ones.
- Throws:
IllegalArgumentException
- if either 0 collectors were input, or all collectors arenull
.
- Filters out the
-
acceptsDocsOutOfOrder
public boolean acceptsDocsOutOfOrder()Description copied from class:Collector
Returntrue
if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) toCollector.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 theCollector
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.- Specified by:
acceptsDocsOutOfOrder
in classCollector
-
collect
Description copied from class:Collector
Called once for every document matching a query, with the unbased document number.Note: The collection of the current segment can be terminated by throwing a
CollectionTerminatedException
. In this case, the last docs of the currentAtomicReaderContext
will be skipped andIndexSearcher
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)
orIndexReader.document(int)
on every hit. Doing so can slow searches by an order of magnitude or more.- Specified by:
collect
in classCollector
- Throws:
IOException
-
setNextReader
Description copied from class:Collector
Called before collecting from eachAtomicReaderContext
. All doc ids inCollector.collect(int)
will correspond toIndexReaderContext.reader()
. AddAtomicReaderContext.docBase
to the currentIndexReaderContext.reader()
's internal document id to re-base ids inCollector.collect(int)
.- Specified by:
setNextReader
in classCollector
- Parameters:
context
- next atomic reader context- Throws:
IOException
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setScorer
Description copied from class:Collector
Called before successive calls toCollector.collect(int)
. Implementations that need the score of the current document (passed-in toCollector.collect(int)
), should save the passed-in Scorer and call scorer.score() when needed.- Specified by:
setScorer
in classCollector
- Throws:
IOException
-