Package io.helidon.security.providers

Interface EvictableCache<K,V>

Type Parameters:

K - type of keys in this cache

V - type of values in this cache

public interface EvictableCache<K,V>

Generic cache with eviction and max size.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	EvictableCache.Builder<K,V>	Builder to create instances of EvictableCache.

Field Summary

Fields

Modifier and Type	Field	Description
static long	CACHE_EVICT_DELAY_MINUTES	Default eviction delay in minutes (how long to wait after the cache is started).
static long	CACHE_EVICT_PERIOD_MINUTES	Default eviction period in minutes (how often to evict records).
static long	CACHE_MAX_SIZE	Maximal number of records in the cache.
static long	CACHE_TIMEOUT_MINUTES	Default timeout of records in minutes (inactivity timeout).
static long	EVICT_PARALLELISM_THRESHOLD	Parameter to ConcurrentHashMap.forEachKey(long, Consumer) used for eviction.

Method Summary

Modifier and Type	Method	Description
static <K,V> EvictableCache.Builder<K,V>	builder()	Create a new builder for a cache.
default void	close()	Close this cache.
default java.util.Optional<V>	computeValue(K key, java.util.function.Supplier<java.util.Optional<V>> valueSupplier)	Either return a cached value or compute it and cache it.
static <K,V> EvictableCache<K,V>	create()	Create a new cache with default values.
static <K,V> EvictableCache<K,V>	create(Config config)	Create a new cache and configure it from the provided configuration.
static <K,V> EvictableCache<K,V>	from(Config config)	Deprecated. Do not use directly, please use create(Config)
default java.util.Optional<V>	get(K key)	Get current cached value if valid.
static <K,V> EvictableCache<K,V>	noCache()	Create a new cache that is not a cache (e.g.
default java.util.Optional<V>	remove(K key)	Remove a key from the cache.
default int	size()	Current size of the cache.

Field Detail

CACHE_TIMEOUT_MINUTES

static final long CACHE_TIMEOUT_MINUTES

Default timeout of records in minutes (inactivity timeout).

See Also:

Constant Field Values

CACHE_EVICT_PERIOD_MINUTES

static final long CACHE_EVICT_PERIOD_MINUTES

Default eviction period in minutes (how often to evict records).

See Also:

Constant Field Values

CACHE_EVICT_DELAY_MINUTES

static final long CACHE_EVICT_DELAY_MINUTES

Default eviction delay in minutes (how long to wait after the cache is started).

See Also:

Constant Field Values

CACHE_MAX_SIZE

static final long CACHE_MAX_SIZE

Maximal number of records in the cache. If the cache is full, no caching is done and the supplier of value is called for every uncached value.

See Also:

Constant Field Values

EVICT_PARALLELISM_THRESHOLD

static final long EVICT_PARALLELISM_THRESHOLD

Parameter to ConcurrentHashMap.forEachKey(long, Consumer) used for eviction.

See Also:

Constant Field Values

Method Detail

builder

static <K,V> EvictableCache.Builder<K,V> builder()

Create a new builder for a cache.

Type Parameters:

K - type of keys in the cache

V - type of values in the cache

Returns:

a builder to build the cache

create

static <K,V> EvictableCache<K,V> create()

Create a new cache with default values.

Type Parameters:

K - type of keys in the cache

V - type of values in the cache

Returns:

new cache built with default values

create

static <K,V> EvictableCache<K,V> create(Config config)

Create a new cache and configure it from the provided configuration. See EvictableCache.Builder.fromConfig(Config) for the list of configuration keys.

Type Parameters:

K - type of keys in the cache

V - type of values in the cache

Parameters:

config - config to read configuration of this cache from

Returns:

new cache configured from config

from

@Deprecated
static <K,V> EvictableCache<K,V> from(Config config)

Deprecated. Do not use directly, please use create(Config)

This method has same semantics as create(Config) and is here to allow automatic loading of instances from config using Config.as(Class).

Type Parameters:

K - type of keys in the cache

V - type of values in the cache

Parameters:

config - config to read configuration of this cache from

Returns:

new cache configured from config

noCache

static <K,V> EvictableCache<K,V> noCache()

Create a new cache that is not a cache (e.g. never caches, delegates all calls to the Supplier in computeValue(Object, Supplier).

Type Parameters:

K - Type of keys

V - Type of values

Returns:

a new instance that is not caching

remove

default java.util.Optional<V> remove(K key)

Remove a key from the cache. Return the value if it was cached and valid.

Parameters:

key - key to remove

Returns:

value if it was removed and valid, empty otherwise

get

default java.util.Optional<V> get(K key)

Get current cached value if valid.

Parameters:

key - key to use

Returns:

current value in the cache or empty if not present (or invalid)

size

default int size()

Current size of the cache. As this cache is using ConcurrentHashMap as backing store, be aware that this value is not guaranteed to be consistent, as puts and removed may be happening in parallel.

Returns:

current size of the cache (including valid and invalid - not yet evicted - values)

computeValue

default java.util.Optional<V> computeValue(K key,
                                           java.util.function.Supplier<java.util.Optional<V>> valueSupplier)

Either return a cached value or compute it and cache it.

Parameters:

key - key to check/insert value for

valueSupplier - supplier called if the value is not yet cached, or is invalid

Returns:

current value from the cache, or computed value from the supplier

close

default void close()

Close this cache. Carry out shutdown tasks (e.g. shutting down eviction thread).