com.atlassian.jira.issue.statistics.util

Class OneDimensionalObjectHitCollector

java.lang.Object

org.apache.lucene.search.SimpleCollector

com.atlassian.jira.issue.statistics.util.OneDimensionalObjectHitCollector

All Implemented Interfaces:

org.apache.lucene.search.Collector, org.apache.lucene.search.LeafCollector

public class OneDimensionalObjectHitCollector
extends org.apache.lucene.search.SimpleCollector

A HitCollector that creates a doc -> object mapping. This is useful for collecting documents where there are a limited number of terms. The caching also ensures that if multiple searches sort on the same terms, the doc -> object mapping is maintained.

This HitCollector can be quite memory intensive, however the cache is stored with a weak reference, so it will be garbage collected.

This HitCollector differs from OneDimensionalTermHitCollector in that it performs the term -> object conversion here, rather than later. This is more expensive, but useful for StatisticsMappers that perform some sort of runtime conversion / translation (eg a StatisticsMapper that groups dates by Month, or groups users by email domain name).

Constructor Summary

Constructors

Constructor and Description
OneDimensionalObjectHitCollector(String fieldName, StatisticsMapper statisticsMapper, Map result) Creates a normal one-dimensional object hit collector.
OneDimensionalObjectHitCollector(String fieldName, StatisticsMapper statisticsMapper, Map result, boolean isUnique) Allows the caller to specify whether or not the hit collector may assume that the field will never have more than one value for any issue.

Method Summary

Modifier and Type	Method and Description
void	collect(int i)
protected void	doSetNextReader(org.apache.lucene.index.LeafReaderContext context)
boolean	needsScores()
void	setScorer(org.apache.lucene.search.Scorer scorer)

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

Constructor Detail

OneDimensionalObjectHitCollector

public OneDimensionalObjectHitCollector(String fieldName,
                                        StatisticsMapper statisticsMapper,
                                        Map result)

Creates a normal one-dimensional object hit collector. This is equivalent to OneDimensionalObjectHitCollector(String, StatisticsMapper, Map, boolean)} with false provided for isUnique, which should be safe for use with all fields. However, if it is known in advance that the field contains at most one value for the field, then specifying isUnique will be more efficient.

Parameters:

statisticsMapper - provides the information required to map the field

result - the map to which the result will be published

OneDimensionalObjectHitCollector

@ExperimentalApi
public OneDimensionalObjectHitCollector(String fieldName,
                                                         StatisticsMapper statisticsMapper,
                                                         Map result,
                                                         boolean isUnique)

Allows the caller to specify whether or not the hit collector may assume that the field will never have more than one value for any issue. This allows the hit collector to be much more efficient in gathering the data for that field, but it will give incorrect results if the field can contain multiple values. Examples of suitable fields where isUnique should be set include the project id, issue type, created date, and resolved date.

Parameters:

statisticsMapper - provides the information required to map the field

result - the map to which the result will be published

isUnique - true if the field can safely be assumed to have at most one value for any issue; false if the field might be allowed to contain multiple values per issue

Method Detail

collect

public void collect(int i)
             throws IOException

Specified by:

collect in interface org.apache.lucene.search.LeafCollector

Specified by:

collect in class org.apache.lucene.search.SimpleCollector

Throws:

IOException

setScorer

public void setScorer(org.apache.lucene.search.Scorer scorer)
               throws IOException

Specified by:

setScorer in interface org.apache.lucene.search.LeafCollector

Overrides:

setScorer in class org.apache.lucene.search.SimpleCollector

Throws:

IOException

doSetNextReader

protected void doSetNextReader(org.apache.lucene.index.LeafReaderContext context)
                        throws IOException

Overrides:

doSetNextReader in class org.apache.lucene.search.SimpleCollector

Throws:

IOException

needsScores

public boolean needsScores()