org.apache.lucene.search
Class NRTManager

java.lang.Object
  org.apache.lucene.search.ReferenceManager<IndexSearcher>
      org.apache.lucene.search.NRTManager

All Implemented Interfaces:

Closeable

public class NRTManager
extends ReferenceManager<IndexSearcher>

Utility class to manage sharing near-real-time searchers across multiple searching thread. The difference vs SearcherManager is that this class enables individual requests to wait until specific indexing changes are visible.

You must create an IndexWriter, then create a NRTManager.TrackingIndexWriter from it, and pass that to the NRTManager. You may want to create two NRTManagers, once that always applies deletes on refresh and one that does not. In this case you should use a single NRTManager.TrackingIndexWriter instance for both.

Then, use ReferenceManager.acquire() to obtain the IndexSearcher, and ReferenceManager.release(G) (ideally, from within a finally clause) to release it.

NOTE: to use this class, you must call ReferenceManager.maybeRefresh() periodically. The NRTManagerReopenThread is a simple class to do this on a periodic basis, and reopens more quickly if a request is waiting. If you implement your own reopener, be sure to call addWaitingListener(org.apache.lucene.search.NRTManager.WaitingListener) so your reopener is notified when a caller is waiting for a specific generation searcher.

See Also:

SearcherFactory

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

Nested Class Summary

static class	NRTManager.TrackingIndexWriter Class that tracks changes to a delegated IndexWriter.
static interface	NRTManager.WaitingListener NRTManager invokes this interface to notify it when a caller is waiting for a specific generation searcher to be visible.

Field Summary

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

current

Constructor Summary

NRTManager(NRTManager.TrackingIndexWriter writer, SearcherFactory searcherFactory)
Create new NRTManager.

NRTManager(NRTManager.TrackingIndexWriter writer, SearcherFactory searcherFactory, boolean applyAllDeletes)
Expert: just like NRTManager(TrackingIndexWriter,SearcherFactory), but you can also specify whether each reopened searcher must apply deletes.

Method Summary

void	addWaitingListener(NRTManager.WaitingListener l) Adds a listener, to be notified when a caller is waiting for a specific generation searcher to be visible.
protected void	afterClose() Called after close(), so subclass can free any resources.
protected void	afterRefresh() Called after swapReference has installed a new instance.
protected void	decRef(IndexSearcher reference) Decrement reference counting on the given reference.
long	getCurrentSearchingGen() Returns generation of current searcher.
boolean	isSearcherCurrent() Returns true if no changes have occured since this searcher ie.
protected IndexSearcher	refreshIfNeeded(IndexSearcher referenceToRefresh) Refresh the given reference if needed.
void	removeWaitingListener(NRTManager.WaitingListener l) Remove a listener added with addWaitingListener(org.apache.lucene.search.NRTManager.WaitingListener).
protected boolean	tryIncRef(IndexSearcher reference) Try to increment reference counting on the given reference.
void	waitForGeneration(long targetGen) Waits for the target generation to become visible in the searcher.
void	waitForGeneration(long targetGen, long time, TimeUnit unit) Waits for the target generation to become visible in the searcher.

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

acquire, close, maybeRefresh, maybeRefreshBlocking, release

Methods inherited from class java.lang.Object

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

Constructor Detail

NRTManager

public NRTManager(NRTManager.TrackingIndexWriter writer,
                  SearcherFactory searcherFactory)
           throws IOException

Create new NRTManager.

Parameters:

writer - TrackingIndexWriter to open near-real-time readers

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

Throws:

IOException

NRTManager

public NRTManager(NRTManager.TrackingIndexWriter writer,
                  SearcherFactory searcherFactory,
                  boolean applyAllDeletes)
           throws IOException

Expert: just like NRTManager(TrackingIndexWriter,SearcherFactory), but you can also specify whether each reopened searcher must apply deletes. This is useful for cases where certain uses can tolerate seeing some deleted docs, since reopen time is faster if deletes need not be applied.

Throws:

IOException

Method Detail

decRef

protected void decRef(IndexSearcher reference)
               throws IOException

Description copied from class: ReferenceManager

Decrement reference counting on the given reference.

Specified by:

decRef in class ReferenceManager<IndexSearcher>

Throws:

IOException

tryIncRef

protected boolean tryIncRef(IndexSearcher reference)

Description copied from class: ReferenceManager

Try to increment reference counting on the given reference. Return true if the operation was successful.

Specified by:

tryIncRef in class ReferenceManager<IndexSearcher>

addWaitingListener

public void addWaitingListener(NRTManager.WaitingListener l)

Adds a listener, to be notified when a caller is waiting for a specific generation searcher to be visible.

removeWaitingListener

public void removeWaitingListener(NRTManager.WaitingListener l)

Remove a listener added with addWaitingListener(org.apache.lucene.search.NRTManager.WaitingListener).

waitForGeneration

public void waitForGeneration(long targetGen)

Waits for the target generation to become visible in the searcher. If the current searcher is older than the target generation, this method will block until the searcher is reopened, by another via ReferenceManager.maybeRefresh() or until the NRTManager is closed.

Parameters:

targetGen - the generation to wait for

waitForGeneration

public void waitForGeneration(long targetGen,
                              long time,
                              TimeUnit unit)

Waits for the target generation to become visible in the searcher. If the current searcher is older than the target generation, this method will block until the searcher has been reopened by another thread via ReferenceManager.maybeRefresh(), the given waiting time has elapsed, or until the NRTManager is closed.

NOTE: if the waiting time elapses before the requested target generation is available the current SearcherManager is returned instead.

Parameters:

targetGen - the generation to wait for

time - the time to wait for the target generation

unit - the waiting time's time unit

getCurrentSearchingGen

public long getCurrentSearchingGen()

Returns generation of current searcher.

refreshIfNeeded

protected IndexSearcher refreshIfNeeded(IndexSearcher referenceToRefresh)
                                 throws IOException

Description copied from class: ReferenceManager

Refresh the given reference if needed. Returns null if no refresh was needed, otherwise a new refreshed reference.

Specified by:

refreshIfNeeded in class ReferenceManager<IndexSearcher>

Throws:

IOException

afterRefresh

protected void afterRefresh()

Description copied from class: ReferenceManager

Called after swapReference has installed a new instance.

Overrides:

afterRefresh in class ReferenceManager<IndexSearcher>

afterClose

protected void afterClose()
                   throws IOException

Description copied from class: ReferenceManager

Called after close(), so subclass can free any resources.

Overrides:

afterClose in class ReferenceManager<IndexSearcher>

Throws:

IOException

isSearcherCurrent

public boolean isSearcherCurrent()
                          throws IOException

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

Throws:

IOException

See Also:

DirectoryReader.isCurrent()