org.apache.lucene.search

Class SimpleCollector

java.lang.Object

org.apache.lucene.search.SimpleCollector

All Implemented Interfaces:

Collector, LeafCollector

Direct Known Subclasses:

TopDocsCollector, TotalHitCountCollector

public abstract class SimpleCollector
extends Object
implements Collector, LeafCollector

Base Collector implementation that is used to collect all contexts.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Constructor Summary

Constructors

Constructor and Description
SimpleCollector()

Method Summary

Methods

Modifier and Type	Method and Description
abstract boolean	acceptsDocsOutOfOrder() Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to LeafCollector.collect(int).
abstract void	collect(int doc) Called once for every document matching a query, with the unbased document number.
protected void	doSetNextReader(AtomicReaderContext context) This method is called before collecting context.
LeafCollector	getLeafCollector(AtomicReaderContext context) Create a new collector to collect the given context.
void	setScorer(Scorer scorer) Called before successive calls to LeafCollector.collect(int).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SimpleCollector

public SimpleCollector()

Method Detail

getLeafCollector

public final LeafCollector getLeafCollector(AtomicReaderContext context)
                                     throws IOException

Description copied from interface: Collector

Create a new collector to collect the given context.

Specified by:

getLeafCollector in interface Collector

Parameters:

context - next atomic reader context

Throws:

IOException

doSetNextReader

protected void doSetNextReader(AtomicReaderContext context)
                        throws IOException

This method is called before collecting context.

Throws:

IOException

setScorer

public 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

Throws:

IOException

acceptsDocsOutOfOrder

public abstract boolean acceptsDocsOutOfOrder()

Description copied from interface: LeafCollector

Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to LeafCollector.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.

Specified by:

acceptsDocsOutOfOrder in interface LeafCollector

collect

public abstract 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 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.

Specified by:

collect in interface LeafCollector

Throws:

IOException