Package org.apache.lucene.search

Class SearcherManager

java.lang.Object

org.apache.lucene.search.ReferenceManager<IndexSearcher>

org.apache.lucene.search.SearcherManager

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public final class SearcherManager
extends ReferenceManager<IndexSearcher>

Utility class to safely share IndexSearcher instances across multiple threads, while periodically reopening. This class ensures each searcher is closed only once all threads have finished using it.

Use ReferenceManager.acquire() to obtain the current searcher, and ReferenceManager.release(G) to release it, like this:

 IndexSearcher s = manager.acquire();
 try {
   // Do searching, doc retrieval, etc. with s
 } finally {
   manager.release(s);
 }
 // Do not use s after this!
 s = null;
 

In addition you should periodically call ReferenceManager.maybeRefresh(). While it's possible to call this just before running each query, this is discouraged since it penalizes the unlucky queries that do the reopen. It's better to use a separate background thread, that periodically calls maybeReopen. Finally, be sure to call ReferenceManager.close() once you are done.

See Also:

SearcherFactory

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.search.ReferenceManager

ReferenceManager.RefreshListener

Constructor Summary

Constructors

Constructor	Description
SearcherManager(IndexWriter writer, boolean applyAllDeletes, SearcherFactory searcherFactory)	Creates and returns a new SearcherManager from the given IndexWriter.
SearcherManager(Directory dir, SearcherFactory searcherFactory)	Creates and returns a new SearcherManager from the given Directory.

Method Summary

Modifier and Type	Method	Description
static IndexSearcher	getSearcher(SearcherFactory searcherFactory, IndexReader reader)	Expert: creates a searcher from the provided IndexReader using the provided SearcherFactory.
boolean	isSearcherCurrent()	Returns true if no changes have occured since this searcher ie.

Methods inherited from class org.apache.lucene.search.ReferenceManager

acquire, addListener, close, maybeRefresh, maybeRefreshBlocking, release, removeListener

Methods inherited from class java.lang.Object

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

Constructor Detail

SearcherManager

public SearcherManager(IndexWriter writer,
                       boolean applyAllDeletes,
                       SearcherFactory searcherFactory)
                throws java.io.IOException

Creates and returns a new SearcherManager from the given IndexWriter.

Parameters:

writer - the IndexWriter to open the IndexReader from.

applyAllDeletes - If true, all buffered deletes will be applied (made visible) in the IndexSearcher / DirectoryReader. If false, the deletes may or may not be applied, but remain buffered (in IndexWriter) so that they will be applied in the future. Applying deletes can be costly, so if your app can tolerate deleted documents being returned you might gain some performance by passing false. See DirectoryReader.openIfChanged(DirectoryReader, IndexWriter, boolean).

searcherFactory - An optional SearcherFactory. Pass null if you don't require the searcher to be warmed before going live or other custom behavior.

Throws:

java.io.IOException - if there is a low-level I/O error

SearcherManager

public SearcherManager(Directory dir,
                       SearcherFactory searcherFactory)
                throws java.io.IOException

Creates and returns a new SearcherManager from the given Directory.

Parameters:

dir - the directory to open the DirectoryReader on.

searcherFactory - An optional SearcherFactory. Pass null if you don't require the searcher to be warmed before going live or other custom behavior.

Throws:

java.io.IOException - if there is a low-level I/O error

Method Detail

isSearcherCurrent

public boolean isSearcherCurrent()
                          throws java.io.IOException

Returns true if no changes have occured since this searcher ie. reader was opened, otherwise false.

Throws:

java.io.IOException

See Also:

DirectoryReader.isCurrent()

getSearcher

public static IndexSearcher getSearcher(SearcherFactory searcherFactory,
                                        IndexReader reader)
                                 throws java.io.IOException

Expert: creates a searcher from the provided IndexReader using the provided SearcherFactory. NOTE: this decRefs incoming reader on throwing an exception.

Throws:

java.io.IOException