org.apache.jackrabbit.oak.segment.spi.persistence.persistentcache

Class AbstractPersistentCache

java.lang.Object

org.apache.jackrabbit.oak.segment.spi.persistence.persistentcache.AbstractPersistentCache

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, PersistentCache

Direct Known Subclasses:

PersistentDiskCache, PersistentRedisCache

public abstract class AbstractPersistentCache
extends java.lang.Object
implements PersistentCache, java.io.Closeable

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.concurrent.atomic.AtomicLong	cacheSize
protected java.util.concurrent.ExecutorService	executor
protected PersistentCache	nextCache
protected SegmentCacheStats	segmentCacheStats
static int	THREADS
protected java.util.Set<java.lang.String>	writesPending

Constructor Summary

Constructors

Constructor and Description
AbstractPersistentCache()

Method Summary

Modifier and Type	Method and Description
void	close()
@NotNull AbstractCacheStats	getCacheStats()
int	getWritesPending()
PersistentCache	linkWith(AbstractPersistentCache nextCache)
Buffer	readSegment(long msb, long lsb, @NotNull java.util.concurrent.Callable<Buffer> loader) Reads the segment from cache.
protected abstract Buffer	readSegmentInternal(long msb, long lsb) Reads the segment from the cache.
protected void	recordCacheLoadTimeInternal(long loadTime, boolean successful) Records time spent to load data from external source, after cache miss.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.jackrabbit.oak.segment.spi.persistence.persistentcache.PersistentCache

cleanUp, containsSegment, writeSegment

Field Detail

THREADS

public static final int THREADS

executor

protected java.util.concurrent.ExecutorService executor

cacheSize

protected java.util.concurrent.atomic.AtomicLong cacheSize

nextCache

protected PersistentCache nextCache

writesPending

protected final java.util.Set<java.lang.String> writesPending

segmentCacheStats

protected SegmentCacheStats segmentCacheStats

Constructor Detail

AbstractPersistentCache

public AbstractPersistentCache()

Method Detail

linkWith

public PersistentCache linkWith(AbstractPersistentCache nextCache)

readSegment

public Buffer readSegment(long msb,
                          long lsb,
                          @NotNull
                          @NotNull java.util.concurrent.Callable<Buffer> loader)

Description copied from interface: PersistentCache

Reads the segment from cache.

Specified by:

readSegment in interface PersistentCache

Parameters:

msb - the most significant bits of the identifier of the segment

lsb - the least significant bits of the identifier of the segment

loader - in case of cache miss, with loader.call() missing element will be retrieved

Returns:

byte buffer containing the segment data or null if the segment doesn't exist

readSegmentInternal

protected abstract Buffer readSegmentInternal(long msb,
                                              long lsb)

Reads the segment from the cache. If segment is not found, this method does not query next cache that was set with linkWith(AbstractPersistentCache)

Parameters:

msb - the most significant bits of the identifier of the segment

lsb - the least significant bits of the identifier of the segment

Returns:

byte buffer containing the segment data or null if the segment doesn't exist

recordCacheLoadTimeInternal

protected final void recordCacheLoadTimeInternal(long loadTime,
                                                 boolean successful)

Records time spent to load data from external source, after cache miss.

Parameters:

loadTime - load time in nanoseconds

successful - indicates whether loading of the segment into cache was successful

getCacheStats

@NotNull
public @NotNull AbstractCacheStats getCacheStats()

Returns:

Statistics for this cache.

close

public void close()

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

getWritesPending

public int getWritesPending()