FacetsCollector (Grandparent POM for Apache Lucene Core and Apache Solr 5.3.0 API)

java.lang.Object
- org.apache.lucene.search.SimpleCollector
- - org.apache.lucene.facet.FacetsCollector

All Implemented Interfaces:

Collector, LeafCollector

Direct Known Subclasses:

RandomSamplingFacetsCollector
```
public class FacetsCollector
extends SimpleCollector
implements Collector
```
Collects hits for subsequent faceting. Once you've run a search and collect hits into this, instantiate one of the Facets subclasses to do the facet counting. Use the search utility methods to perform an "ordinary" search but also collect into a Collector.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`FacetsCollector.Docs` Used during collection to record matching docs and then return a `DocIdSet` that contains them.
`static class`	`FacetsCollector.MatchingDocs` Holds the documents that were matched in the `LeafReaderContext`.

Constructor Summary

Constructors
Constructor and Description
`FacetsCollector()` Default constructor
`FacetsCollector(boolean keepScores)` Create this; if `keepScores` is true then a float[] is allocated to hold score of all hits.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`collect(int doc)` Called once for every document matching a query, with the unbased document number.
`protected FacetsCollector.Docs`	`createDocs(int maxDoc)` Creates a `FacetsCollector.Docs` to record hits.
`protected void`	`doSetNextReader(LeafReaderContext context)` This method is called before collecting `context`.
`boolean`	`getKeepScores()` True if scores were saved.
`List<FacetsCollector.MatchingDocs>`	`getMatchingDocs()` Returns the documents matched by the query, one `FacetsCollector.MatchingDocs` per visited segment.
`boolean`	`needsScores()` Indicates if document scores are needed by this collector.
`static TopDocs`	`search(IndexSearcher searcher, Query q, int n, Collector fc)` Utility method, to search and also collect all hits into the provided `Collector`.
`static TopFieldDocs`	`search(IndexSearcher searcher, Query q, int n, Sort sort, boolean doDocScores, boolean doMaxScore, Collector fc)` Utility method, to search and also collect all hits into the provided `Collector`.
`static TopFieldDocs`	`search(IndexSearcher searcher, Query q, int n, Sort sort, Collector fc)` Utility method, to search and also collect all hits into the provided `Collector`.
`static TopDocs`	`searchAfter(IndexSearcher searcher, ScoreDoc after, Query q, int n, Collector fc)` Utility method, to search and also collect all hits into the provided `Collector`.
`static TopDocs`	`searchAfter(IndexSearcher searcher, ScoreDoc after, Query q, int n, Sort sort, boolean doDocScores, boolean doMaxScore, Collector fc)` Utility method, to search and also collect all hits into the provided `Collector`.
`static TopDocs`	`searchAfter(IndexSearcher searcher, ScoreDoc after, Query q, int n, Sort sort, Collector fc)` Utility method, to search and also collect all hits into the provided `Collector`.
`void`	`setScorer(Scorer scorer)` Called before successive calls to `LeafCollector.collect(int)`.

Methods inherited from class org.apache.lucene.search.SimpleCollector
getLeafCollector

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.lucene.search.Collector
getLeafCollector

Constructor Detail
- FacetsCollector
```
public FacetsCollector()
```
  Default constructor
- FacetsCollector
```
public FacetsCollector(boolean keepScores)
```
  Create this; if keepScores is true then a float[] is allocated to hold score of all hits.

Method Detail

createDocs
```
protected FacetsCollector.Docs createDocs(int maxDoc)
```
Creates a FacetsCollector.Docs to record hits. The default uses FixedBitSet to record hits and you can override to e.g. record the docs in your own DocIdSet.

getKeepScores
```
public final boolean getKeepScores()
```
True if scores were saved.

getMatchingDocs
```
public List<FacetsCollector.MatchingDocs> getMatchingDocs()
```
Returns the documents matched by the query, one FacetsCollector.MatchingDocs per visited segment.

collect
```
public final void collect(int doc)
                   throws IOException
```
Description copied from interface: LeafCollector

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 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.

Specified by:

collect in interface LeafCollector

Specified by:

collect in class SimpleCollector

Throws:

IOException

needsScores
```
public boolean needsScores()
```
Description copied from interface: Collector

Indicates if document scores are needed by this collector.

Specified by:

needsScores in interface Collector

Returns:

true if scores are needed.

setScorer
```
public final void setScorer(Scorer scorer)
                     throws IOException
```
Description copied from interface: LeafCollector

Called before successive calls to 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.

Specified by:

setScorer in interface LeafCollector

Overrides:

setScorer in class SimpleCollector

Throws:

IOException

doSetNextReader
```
protected void doSetNextReader(LeafReaderContext context)
                        throws IOException
```
Description copied from class: SimpleCollector

This method is called before collecting context.

Overrides:

doSetNextReader in class SimpleCollector

Throws:

IOException