Class TopScoreDocCollectorManager
- java.lang.Object
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- org.apache.lucene.search.TopScoreDocCollectorManager
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- All Implemented Interfaces:
CollectorManager<TopScoreDocCollector,TopDocs>
public class TopScoreDocCollectorManager extends Object implements CollectorManager<TopScoreDocCollector,TopDocs>
Create a TopScoreDocCollectorManager which uses a shared hit counter to maintain number of hits and a sharedMaxScoreAccumulatorto propagate the minimum score across segmentsNote that a new collectorManager should be created for each search due to its internal states.
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Constructor Summary
Constructors Constructor Description TopScoreDocCollectorManager(int numHits, int totalHitsThreshold)Creates a newTopScoreDocCollectorManagergiven the number of hits to collect and the number of hits to count accurately, with thread-safe internal states.TopScoreDocCollectorManager(int numHits, ScoreDoc after, int totalHitsThreshold)Creates a newTopScoreDocCollectorManagergiven the number of hits to collect and the number of hits to count accurately, with thread-safe internal states.TopScoreDocCollectorManager(int numHits, ScoreDoc after, int totalHitsThreshold, boolean supportsConcurrency)Creates a newTopScoreDocCollectorManagergiven the number of hits to collect and the number of hits to count accurately.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description TopScoreDocCollectornewCollector()Return a newCollector.TopDocsreduce(Collection<TopScoreDocCollector> collectors)Reduce the results of individual collectors into a meaningful result.
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Constructor Detail
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TopScoreDocCollectorManager
public TopScoreDocCollectorManager(int numHits, ScoreDoc after, int totalHitsThreshold, boolean supportsConcurrency)Creates a newTopScoreDocCollectorManagergiven the number of hits to collect and the number of hits to count accurately.NOTE: If the total hit count of the top docs is less than or exactly
totalHitsThresholdthen this value is accurate. On the other hand, if theTopDocs.totalHitsvalue is greater thantotalHitsThresholdthen its value is a lower bound of the hit count. A value ofInteger.MAX_VALUEwill make the hit count accurate but will also likely make query processing slower.NOTE: The instances returned by this method pre-allocate a full array of length
numHits, and fill the array with sentinel objects.- Parameters:
numHits- the number of results to collect.after- the previous doc after which matching docs will be collected.totalHitsThreshold- the number of docs to count accurately. If the query matches more thantotalHitsThresholdhits then its hit count will be a lower bound. On the other hand if the query matches less than or exactlytotalHitsThresholdhits then the hit count of the result will be accurate.Integer.MAX_VALUEmay be used to make the hit count accurate, but this will also make query processing slower.supportsConcurrency- to use thread-safe and slower internal states for count tracking.
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TopScoreDocCollectorManager
public TopScoreDocCollectorManager(int numHits, ScoreDoc after, int totalHitsThreshold)Creates a newTopScoreDocCollectorManagergiven the number of hits to collect and the number of hits to count accurately, with thread-safe internal states.NOTE: If the total hit count of the top docs is less than or exactly
totalHitsThresholdthen this value is accurate. On the other hand, if theTopDocs.totalHitsvalue is greater thantotalHitsThresholdthen its value is a lower bound of the hit count. A value ofInteger.MAX_VALUEwill make the hit count accurate but will also likely make query processing slower.NOTE: The instances returned by this method pre-allocate a full array of length
numHits, and fill the array with sentinel objects.- Parameters:
numHits- the number of results to collect.after- the previous doc after which matching docs will be collected.totalHitsThreshold- the number of docs to count accurately. If the query matches more thantotalHitsThresholdhits then its hit count will be a lower bound. On the other hand if the query matches less than or exactlytotalHitsThresholdhits then the hit count of the result will be accurate.Integer.MAX_VALUEmay be used to make the hit count accurate, but this will also make query processing slower.
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TopScoreDocCollectorManager
public TopScoreDocCollectorManager(int numHits, int totalHitsThreshold)Creates a newTopScoreDocCollectorManagergiven the number of hits to collect and the number of hits to count accurately, with thread-safe internal states.NOTE: If the total hit count of the top docs is less than or exactly
totalHitsThresholdthen this value is accurate. On the other hand, if theTopDocs.totalHitsvalue is greater thantotalHitsThresholdthen its value is a lower bound of the hit count. A value ofInteger.MAX_VALUEwill make the hit count accurate but will also likely make query processing slower.NOTE: The instances returned by this method pre-allocate a full array of length
numHits, and fill the array with sentinel objects.- Parameters:
numHits- the number of results to collect.totalHitsThreshold- the number of docs to count accurately. If the query matches more thantotalHitsThresholdhits then its hit count will be a lower bound. On the other hand if the query matches less than or exactlytotalHitsThresholdhits then the hit count of the result will be accurate.Integer.MAX_VALUEmay be used to make the hit count accurate, but this will also make query processing slower.
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Method Detail
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newCollector
public TopScoreDocCollector newCollector()
Description copied from interface:CollectorManagerReturn a newCollector. This must return a different instance on each call.- Specified by:
newCollectorin interfaceCollectorManager<TopScoreDocCollector,TopDocs>
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reduce
public TopDocs reduce(Collection<TopScoreDocCollector> collectors) throws IOException
Description copied from interface:CollectorManagerReduce the results of individual collectors into a meaningful result. For instance aTopDocsCollectorwould compute thetop docsof each collector and then merge them usingTopDocs.merge(int, TopDocs[]). This method must be called after collection is finished on all provided collectors.- Specified by:
reducein interfaceCollectorManager<TopScoreDocCollector,TopDocs>- Throws:
IOException
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