Interface Policy<K,V>
- All Known Implementing Classes:
BoundedLocalCache.BoundedPolicy
,UnboundedLocalCache.UnboundedPolicy
public interface Policy<K,V>
An access point for inspecting and performing low-level operations based on the cache's runtime
characteristics. These operations are optional and dependent on how the cache was constructed
and what abilities the implementation exposes.
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Nested Class Summary
Nested ClassesModifier and TypeInterfaceDescriptionstatic interface
The low-level operations for a cache with a size-based eviction policy.static interface
The low-level operations for a cache with a fixed expiration policy.static interface
The low-level operations for a cache with a variable expiration policy. -
Method Summary
Modifier and TypeMethodDescription@NonNull Optional
<Policy.Eviction<K, V>> eviction()
Returns access to perform operations based on the maximum size or maximum weight eviction policy.@NonNull Optional
<Policy.Expiration<K, V>> Returns access to perform operations based on the time-to-idle expiration policy.@NonNull Optional
<Policy.Expiration<K, V>> Returns access to perform operations based on the time-to-live expiration policy.default @NonNull Optional
<Policy.VarExpiration<K, V>> Returns access to perform operations based on the variable expiration policy.default @Nullable V
getIfPresentQuietly
(@NonNull Object key) Returns the value associated with thekey
in this cache, ornull
if there is no cached value for thekey
.boolean
Returns whether the cache statistics are being accumulated.@NonNull Optional
<Policy.Expiration<K, V>> Returns access to perform operations based on the time-to-live refresh policy.
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Method Details
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isRecordingStats
boolean isRecordingStats()Returns whether the cache statistics are being accumulated.- Returns:
- if cache statistics are being recorded
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getIfPresentQuietly
Returns the value associated with thekey
in this cache, ornull
if there is no cached value for thekey
. UnlikeCache.getIfPresent(Object)
, this method does not produce any side effects such as updating statistics, the eviction policy, reseting the expiration time, or triggering a refresh.- Parameters:
key
- the key whose associated value is to be returned- Returns:
- the value to which the specified key is mapped, or
null
if this cache contains no mapping for the key - Throws:
NullPointerException
- if the specified key is null
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eviction
@NonNull Optional<Policy.Eviction<K,V>> eviction()Returns access to perform operations based on the maximum size or maximum weight eviction policy. If the cache was not constructed with a size-based bound or the implementation does not support these operations, an emptyOptional
is returned.- Returns:
- access to low-level operations for this cache if an eviction policy is used
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expireAfterAccess
@NonNull Optional<Policy.Expiration<K,V>> expireAfterAccess()Returns access to perform operations based on the time-to-idle expiration policy. This policy determines that an entry should be automatically removed from the cache once a fixed duration has elapsed after the entry's creation, the most recent replacement of its value, or its last access. Access time is reset by all cache read and write operations (includingCache.asMap().get(Object)
andCache.asMap().put(K, V)
), but not by operations on the collection-views ofCache.asMap()
.If the cache was not constructed with access-based expiration or the implementation does not support these operations, an empty
Optional
is returned.- Returns:
- access to low-level operations for this cache if a time-to-idle expiration policy is used
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expireAfterWrite
@NonNull Optional<Policy.Expiration<K,V>> expireAfterWrite()Returns access to perform operations based on the time-to-live expiration policy. This policy determines that an entry should be automatically removed from the cache once a fixed duration has elapsed after the entry's creation, or the most recent replacement of its value.If the cache was not constructed with write-based expiration or the implementation does not support these operations, an empty
Optional
is returned.- Returns:
- access to low-level operations for this cache if a time-to-live expiration policy is used
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expireVariably
Returns access to perform operations based on the variable expiration policy. This policy determines that an entry should be automatically removed from the cache once a per-entry duration has elapsed.If the cache was not constructed with variable expiration or the implementation does not support these operations, an empty
Optional
is returned.- Returns:
- access to low-level operations for this cache if a variable expiration policy is used
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refreshAfterWrite
@NonNull Optional<Policy.Expiration<K,V>> refreshAfterWrite()Returns access to perform operations based on the time-to-live refresh policy. This policy determines that an entry should be automatically reloaded once a fixed duration has elapsed after the entry's creation, or the most recent replacement of its value.If the cache was not constructed with write-based refresh or the implementation does not support these operations, an empty
Optional
is returned.- Returns:
- access to low-level operations for this cache if a time-to-live refresh policy is used
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