Package org.apache.lucene.index

Class MergeScheduler

java.lang.Object

org.apache.lucene.index.MergeScheduler

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

ConcurrentMergeScheduler, NoMergeScheduler, SerialMergeScheduler

public abstract class MergeScheduler
extends Object
implements Closeable

Expert: IndexWriter uses an instance implementing this interface to execute the merges selected by a MergePolicy. The default MergeScheduler is ConcurrentMergeScheduler.

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

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	MergeScheduler.MergeSource	Provides access to new merges and executes the actual merge

Field Summary

Fields

Modifier and Type	Field	Description
protected InfoStream	infoStream	For messages about merge scheduling

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MergeScheduler()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
void	close()	Close this MergeScheduler.
Executor	getIntraMergeExecutor(MergePolicy.OneMerge merge)	Provides an executor for parallelism during a single merge operation.
abstract void	merge(MergeScheduler.MergeSource mergeSource, MergeTrigger trigger)	Run the merges provided by MergeScheduler.MergeSource.getNextMerge().
protected void	message(String message)	Outputs the given message - this method assumes verbose() was called and returned true.
protected boolean	verbose()	Returns true if infoStream messages are enabled.
Directory	wrapForMerge(MergePolicy.OneMerge merge, Directory in)	Wraps the incoming Directory so that we can merge-throttle it using RateLimitedIndexOutput.

Methods inherited from class java.lang.Object

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

Field Detail

infoStream

protected InfoStream infoStream

For messages about merge scheduling

Constructor Detail

MergeScheduler

protected MergeScheduler()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

merge

public abstract void merge(MergeScheduler.MergeSource mergeSource,
                           MergeTrigger trigger)
                    throws IOException

Run the merges provided by MergeScheduler.MergeSource.getNextMerge().

Parameters:

mergeSource - the IndexWriter to obtain the merges from.

trigger - the MergeTrigger that caused this merge to happen

Throws:

IOException

wrapForMerge

public Directory wrapForMerge(MergePolicy.OneMerge merge,
                              Directory in)

Wraps the incoming Directory so that we can merge-throttle it using RateLimitedIndexOutput.

getIntraMergeExecutor

public Executor getIntraMergeExecutor(MergePolicy.OneMerge merge)

Provides an executor for parallelism during a single merge operation. By default, the method returns a SameThreadExecutorService where all intra-merge actions occur in their calling thread.

close

public void close()
           throws IOException

Close this MergeScheduler.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

verbose

protected boolean verbose()

Returns true if infoStream messages are enabled. This method is usually used in conjunction with message(String):

 if (verbose()) {
   message("your message");
 }
 

message

protected void message(String message)

Outputs the given message - this method assumes verbose() was called and returned true.