Package org.apache.jackrabbit.oak.index.indexer.document.flatfile

Class AheadOfTimeBlobDownloaderThrottler

java.lang.Object

org.apache.jackrabbit.oak.index.indexer.document.flatfile.AheadOfTimeBlobDownloaderThrottler

public class AheadOfTimeBlobDownloaderThrottler
extends Object

Tracks a prefetch window for the AOT downloader. This class keeps a window from {startPosition, endPosition} together with an estimation of the data that was downloaded inside this window. It exposes two operations:

• reserveSpaceForBlob(long, long) - Reserves space to download blob at the given position and size, blocking until enough space is available.
• advanceIndexer(long) - Advances the window until the given position, removing from the window any positions lower or equal than the new index.

Constructor Summary

Constructors

Constructor	Description
AheadOfTimeBlobDownloaderThrottler(int maxWindowSizeNumberOfBlobs, long maxWindowSizeBytes)

Method Summary

Modifier and Type	Method	Description
void	advanceIndexer(long indexerPosition)	Advances the indexer to the given position.
String	formatStats()
long	getAvailableWindowBytes()
long	getAvailableWindowSize()
boolean	reserveSpaceForBlob(long position, long length)	Reserves space for a blob to be downloaded.

Methods inherited from class java.lang.Object

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

Constructor Detail

AheadOfTimeBlobDownloaderThrottler

public AheadOfTimeBlobDownloaderThrottler(int maxWindowSizeNumberOfBlobs,
                                          long maxWindowSizeBytes)

Parameters:

maxWindowSizeBytes - How many bytes can be downloaded ahead of the indexer.

maxWindowSizeNumberOfBlobs - How many blobs can be downloaded ahead of the indexer.

Method Detail

reserveSpaceForBlob

public boolean reserveSpaceForBlob(long position,
                                   long length)
                            throws InterruptedException

Reserves space for a blob to be downloaded. This method blocks until there is enough space in the prefetch window. If the position of the reservation is lower or equal to the indexer position, the reservation is ignored.

Parameters:

position - The position of the blob to be downloaded.

length - The length of the blob to be downloaded.

Returns:

true if space was reserved, false if the indexer is already ahead of the position of the blob.

Throws:

InterruptedException

getAvailableWindowSize

public long getAvailableWindowSize()

getAvailableWindowBytes

public long getAvailableWindowBytes()

advanceIndexer

public void advanceIndexer(long indexerPosition)

Advances the indexer to the given position.

Parameters:

indexerPosition - The new position of the indexer.

formatStats

public String formatStats()