org.apache.jackrabbit.oak.segment

Class RecordCache<T>

java.lang.Object

org.apache.jackrabbit.oak.segment.RecordCache<T>

Type Parameters:

T -

public abstract class RecordCache<T>
extends Object

Partial mapping of keys of type T to values of type RecordId. This is typically used for de-duplicating values that have already been persisted and thus already have a RecordId.

Constructor Summary

Constructors

Constructor and Description
RecordCache()

Method Summary

Methods

Modifier and Type	Method and Description
abstract long	estimateCurrentWeight()
static <T> com.google.common.base.Supplier<RecordCache<T>>	factory(int size)
static <T> com.google.common.base.Supplier<RecordCache<T>>	factory(int size, com.google.common.cache.Weigher<T,RecordId> weigher)
abstract RecordId	get(T key)
com.google.common.cache.CacheStats	getStats()
static <T> RecordCache<T>	newRecordCache(int size) Factory method for creating RecordCache instances.
abstract void	put(T key, RecordId value) Add a mapping from key to value.
abstract long	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

RecordCache

public RecordCache()

Method Detail

put

public abstract void put(@Nonnull
       T key,
       @Nonnull
       RecordId value)

Add a mapping from key to value. Any existing mapping is replaced.

get

@CheckForNull
public abstract RecordId get(@Nonnull
                        T key)

Returns:

The mapping for key, or null if none.

size

public abstract long size()

Returns:

number of mappings

estimateCurrentWeight

public abstract long estimateCurrentWeight()

getStats

@Nonnull
public com.google.common.cache.CacheStats getStats()

Returns:

access statistics for this cache

newRecordCache

@Nonnull
public static <T> RecordCache<T> newRecordCache(int size)

Factory method for creating RecordCache instances. The returned instances are all thread safe. They implement a simple LRU behaviour where the least recently accessed mapping would be replaced when inserting a new mapping would exceed size.

Returns:

A new RecordCache instance of the given size.

factory

@Nonnull
public static <T> com.google.common.base.Supplier<RecordCache<T>> factory(int size,
                                                                  @Nonnull
                                                                  com.google.common.cache.Weigher<T,RecordId> weigher)

Parameters:

size - size of the cache

weigher - Needed to provide an estimation of the cache weight in memory

Returns:

A factory returning RecordCache instances of the given size when invoked.

See Also:

newRecordCache(int)

factory

@Nonnull
public static <T> com.google.common.base.Supplier<RecordCache<T>> factory(int size)

Parameters:

size - size of the cache

Returns:

A factory returning RecordCache instances of the given size when invoked.

See Also:

newRecordCache(int)