Package org.apache.lucene.monitor

Class ParallelMatcher<T extends QueryMatch>

java.lang.Object

org.apache.lucene.monitor.CandidateMatcher<T>

org.apache.lucene.monitor.ParallelMatcher<T>

Type Parameters:

T - the QueryMatch type returned

public class ParallelMatcher<T extends QueryMatch>
extends CandidateMatcher<T>

Matcher class that runs matching queries in parallel.

This class delegates the actual matching to separate CandidateMatcher classes, built from a passed in MatcherFactory.

Use this when individual queries can take a long time to run, and you want to minimize latency. The matcher distributes queries amongst its worker threads using a BlockingQueue, and synchronization overhead may affect performance if the individual queries are very fast.

See Also:

PartitionMatcher

Field Summary

Fields inherited from class org.apache.lucene.monitor.CandidateMatcher

searcher

Method Summary

Modifier and Type	Method	Description
protected void	doFinish()	Called when all monitoring of a batch of documents is complete
static <T extends QueryMatch> MatcherFactory<T>	factory(ExecutorService executor, MatcherFactory<T> matcherFactory)	Create a new MatcherFactory for a ParallelMatcher
static <T extends QueryMatch> MatcherFactory<T>	factory(ExecutorService executor, MatcherFactory<T> matcherFactory, int threads)	Create a new MatcherFactory for a ParallelMatcher
protected void	matchQuery(String queryId, Query matchQuery, Map<String,String> metadata)	Runs the supplied query against this CandidateMatcher's set of documents, storing any resulting match, and recording the query in the presearcher hits
T	resolve(T match1, T match2)	If two matches from the same query are found (for example, two branches of a disjunction), combine them.

Methods inherited from class org.apache.lucene.monitor.CandidateMatcher

addMatch, copyMatches

Methods inherited from class java.lang.Object

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

Method Detail

matchQuery

protected void matchQuery(String queryId,
                          Query matchQuery,
                          Map<String,String> metadata)
                   throws IOException

Description copied from class: CandidateMatcher

Runs the supplied query against this CandidateMatcher's set of documents, storing any resulting match, and recording the query in the presearcher hits

Specified by:

matchQuery in class CandidateMatcher<T extends QueryMatch>

Parameters:

queryId - the query id

matchQuery - the query to run

metadata - the query metadata

Throws:

IOException - on IO errors

resolve

public T resolve(T match1,
                 T match2)

Description copied from class: CandidateMatcher

If two matches from the same query are found (for example, two branches of a disjunction), combine them.

Specified by:

resolve in class CandidateMatcher<T extends QueryMatch>

Parameters:

match1 - the first match found

match2 - the second match found

Returns:

a Match object that combines the two

doFinish

protected void doFinish()

Description copied from class: CandidateMatcher

Called when all monitoring of a batch of documents is complete

Overrides:

doFinish in class CandidateMatcher<T extends QueryMatch>

factory

public static <T extends QueryMatch> MatcherFactory<T> factory(ExecutorService executor,
                                                               MatcherFactory<T> matcherFactory,
                                                               int threads)

Create a new MatcherFactory for a ParallelMatcher

Type Parameters:

T - the type of QueryMatch generated

Parameters:

executor - the ExecutorService to use

matcherFactory - the MatcherFactory to use to create submatchers

threads - the number of threads to use

factory

public static <T extends QueryMatch> MatcherFactory<T> factory(ExecutorService executor,
                                                               MatcherFactory<T> matcherFactory)

Create a new MatcherFactory for a ParallelMatcher

This factory will create a ParallelMatcher that uses as many threads as there are cores available to the JVM (as determined by Runtime.getRuntime().availableProcessors()).

Type Parameters:

T - the type of QueryMatch generated

Parameters:

executor - the ExecutorService to use

matcherFactory - the MatcherFactory to use to create submatchers