Class MemoryAwareCacheSupport<K,V>

java.lang.Object

io.fluxzero.common.caching.MemoryAwareCacheSupport<K,V>

Type Parameters:

K - key type

V - value type

All Implemented Interfaces:

AutoCloseable

public class MemoryAwareCacheSupport<K,V>
extends Object
implements AutoCloseable

A hard-reference, weighted cache with LRU eviction and optional key ordering.

The cache intentionally avoids soft references. Memory ownership is explicit through entry weights and a maximum total weight. A MemoryPressureController may request extra trimming when heap or GC pressure is observed.

Field Summary

Fields

Modifier and Type	Field	Description
static final Duration	DEFAULT_MEMORY_PRESSURE_CHECK_INTERVAL

Constructor Summary

Constructors

Constructor	Description
MemoryAwareCacheSupport(long maxWeight, long maxEntryWeight, ToLongBiFunction<? super K, ? super V> weigher)
MemoryAwareCacheSupport(long maxWeight, long maxEntryWeight, ToLongBiFunction<? super K, ? super V> weigher, Comparator<? super K> keyComparator)
MemoryAwareCacheSupport(long maxWeight, long maxEntryWeight, ToLongBiFunction<? super K, ? super V> weigher, Comparator<? super K> keyComparator, MemoryPressureController memoryPressureController)
MemoryAwareCacheSupport(long maxWeight, long maxEntryWeight, ToLongBiFunction<? super K, ? super V> weigher, Comparator<? super K> keyComparator, MemoryPressureController memoryPressureController, Duration memoryPressureCheckInterval)

Method Summary

Modifier and Type	Method	Description
void	clear()
void	close()
boolean	containsKey(K key)
V	evict(K key, MemoryAwareCacheSupportEviction.Reason reason)	Removes a value and publishes the supplied eviction reason when the key was present.
void	evictBefore(K frontier, boolean inclusive)	Evicts all ordered keys before the supplied frontier.
K	firstKey()
V	get(K key)
List<K>	keys()
K	lastKey()
long	maxEntryWeight()
long	maxWeight()
boolean	put(K key, V value)	Stores a value when it fits the configured entry and total weight constraints.
Registration	registerEvictionListener(Consumer<MemoryAwareCacheSupportEviction<K,V>> listener)
V	remove(K key)
int	size()
boolean	trimForMemoryPressure()	Proactively sheds cached weight according to the configured trim ratio and maximum trim weight when the controller observes memory pressure.
List<V>	valuesFrom(K minKey, boolean inclusive, int maxSize)	Returns cached values ordered by key, starting at minKey.
long	weight()

Methods inherited from class Object

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

Field Details

DEFAULT_MEMORY_PRESSURE_CHECK_INTERVAL

public static final Duration DEFAULT_MEMORY_PRESSURE_CHECK_INTERVAL

Constructor Details

MemoryAwareCacheSupport

public MemoryAwareCacheSupport(long maxWeight,
 long maxEntryWeight,
 ToLongBiFunction<? super K, ? super V> weigher)

MemoryAwareCacheSupport

public MemoryAwareCacheSupport(long maxWeight,
 long maxEntryWeight,
 ToLongBiFunction<? super K, ? super V> weigher,
 Comparator<? super K> keyComparator)

MemoryAwareCacheSupport

public MemoryAwareCacheSupport(long maxWeight,
 long maxEntryWeight,
 ToLongBiFunction<? super K, ? super V> weigher,
 Comparator<? super K> keyComparator,
 MemoryPressureController memoryPressureController)

MemoryAwareCacheSupport

public MemoryAwareCacheSupport(long maxWeight,
 long maxEntryWeight,
 ToLongBiFunction<? super K, ? super V> weigher,
 Comparator<? super K> keyComparator,
 MemoryPressureController memoryPressureController,
 Duration memoryPressureCheckInterval)

Method Details

put

public boolean put(K key,
 V value)

Stores a value when it fits the configured entry and total weight constraints.

Returns:

true if the value remains cached after admission and eviction

get

public V get(K key)

containsKey

public boolean containsKey(K key)

remove

public V remove(K key)

evict

public V evict(K key,
 MemoryAwareCacheSupportEviction.Reason reason)

Removes a value and publishes the supplied eviction reason when the key was present.

clear

public void clear()

size

public int size()

weight

public long weight()

keys

public List<K> keys()

firstKey

public K firstKey()

lastKey

public K lastKey()

maxWeight

public long maxWeight()

maxEntryWeight

public long maxEntryWeight()

valuesFrom

public List<V> valuesFrom(K minKey,
 boolean inclusive,
 int maxSize)

Returns cached values ordered by key, starting at minKey.

evictBefore

public void evictBefore(K frontier,
 boolean inclusive)

Evicts all ordered keys before the supplied frontier.

registerEvictionListener

public Registration registerEvictionListener(Consumer<MemoryAwareCacheSupportEviction<K,V>> listener)

trimForMemoryPressure

public boolean trimForMemoryPressure()

Proactively sheds cached weight according to the configured trim ratio and maximum trim weight when the controller observes memory pressure.

Returns:

true if pressure was observed

close

public void close()

Specified by:

close in interface AutoCloseable