com.trivago.triava.tcache

Class CacheLimit<K,V>

java.lang.Object

com.trivago.triava.tcache.Cache<K,V>

com.trivago.triava.tcache.CacheLimit<K,V>

All Implemented Interfaces:

ActionContext<K,V>, Thread.UncaughtExceptionHandler

public class CacheLimit<K,V>
extends Cache<K,V>

A size limited Cache, that evicts elements asynchronously in the background. The element to be evicted are chosen by the evictionClass,

Author:

cesken

Nested Class Summary

Nested classes/interfaces inherited from class com.trivago.triava.tcache.Cache

Cache.CleanupThread

Field Summary

Fields

Modifier and Type	Field and Description
protected EvictionInterface<K,V>	evictionClass
protected AtomicLong	evictionCount

Fields inherited from class com.trivago.triava.tcache.Cache

jamPolicy, loader, objects

Constructor Summary

Constructors

Constructor and Description
CacheLimit(TCacheFactory factory, Builder<K,V> builder)

Method Summary

Modifier and Type	Method and Description
protected String	configToString()
protected int	elementsToRemove() Determine how many elements to remove.
protected boolean	ensureFreeCapacity() Frees entries, if the Cache is near full.
protected String	evictionConfigInfo()
protected int	evictionExtraSpace(Builder<K,V> builder) Calculates the amount of extra space that we need as eviction extra space in the storage Map.
protected TCacheStatisticsInterface	fillCacheStatistics(TCacheStatisticsInterface cacheStatistic) Fills the given cache statistics object.
protected boolean	isFull() Returns whether the Cache is full.
protected boolean	isOverfull() Returns whether the cache is overfull.
void	shutdownCustomImpl() Shuts down the Eviction thread.

Methods inherited from class com.trivago.triava.tcache.Cache

activateTimeSource, cacheWriter, clear, close, configuration, containsKey, enableManagement, enableStatistics, expireUntil, gatedHolder, get, getAndPut, getAndReplace, getCacheHitrate, id, isClosed, isManagementEnabled, isStatisticsEnabled, iterator, iteratorWithTouch, joinSimple, jsr107cache, keySet, listeners, put, put, putIfAbsent, putIfAbsent, putToMap, remove, remove, removeAndRelease, replace, reportSize, setLogger, size, statistics, statisticsCalculator, stopAndClear, toString, uncaughtException

Methods inherited from class java.lang.Object

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

Field Detail

evictionClass

protected EvictionInterface<K,V> evictionClass

evictionCount

protected final AtomicLong evictionCount

Constructor Detail

CacheLimit

public CacheLimit(TCacheFactory factory,
                  Builder<K,V> builder)

Method Detail

isFull

protected boolean isFull()

Returns whether the Cache is full. We declare the Cache full, when it has reached the number of expected elements, even though there may be some extra eviction space available.

Returns:

true, if the cache is full

isOverfull

protected boolean isOverfull()

Returns whether the cache is overfull. We declare the Cache full, when it has reached the blocking position.

Returns:

true, if the cache is overfull

evictionExtraSpace

protected int evictionExtraSpace(Builder<K,V> builder)

Calculates the amount of extra space that we need as eviction extra space in the storage Map. The amount returned is the number of extra elements to allocate in the Map. A StorageBackend can use that.

Internally this method calculates some more numbers: 0 // Empty private int evictUntilAtLeast; // Position below userDataElements private int userDataElements; // Expected elements, as given by user private int blockStartAt; // Block mark private int evictNormallyElements; // SET DURING CONSTRUCTION

Overrides:

evictionExtraSpace in class Cache<K,V>

Parameters:

builder - The builder containing the configuration

Returns:

The number of extra elements required in the storage Map.

elementsToRemove

protected int elementsToRemove()

Determine how many elements to remove. The goal is to reach the interval [ evictUntilAtLeast, userDataElements]. Typically we would try to evict evictNormallyElements elements.

Returns:

The number of elements to remove

shutdownCustomImpl

public void shutdownCustomImpl()

Shuts down the Eviction thread.

ensureFreeCapacity

protected boolean ensureFreeCapacity()

Frees entries, if the Cache is near full.

Overrides:

ensureFreeCapacity in class Cache<K,V>

Returns:

true, if free capacity can be granted.

fillCacheStatistics

protected TCacheStatisticsInterface fillCacheStatistics(TCacheStatisticsInterface cacheStatistic)

Description copied from class: Cache

Fills the given cache statistics object.

Overrides:

fillCacheStatistics in class Cache<K,V>

Parameters:

cacheStatistic - The statistics object to fill

Returns:

The CacheStatistic object

configToString

protected String configToString()

Overrides:

configToString in class Cache<K,V>

evictionConfigInfo

protected String evictionConfigInfo()