com.github.benmanes.caffeine.cache

Interface Policy.VarExpiration<K,V>

Enclosing interface:

Policy<K,V>

public static interface Policy.VarExpiration<K,V>

The low-level operations for a cache with a variable expiration policy.

Method Summary

Modifier and Type	Method and Description
OptionalLong	getExpiresAfter(K key, TimeUnit unit) Returns the duration until the entry should be automatically removed.
Map<K,V>	oldest(int limit) Returns an unmodifiable snapshot Map view of the cache with ordered traversal.
default void	put(K key, V value, long duration, TimeUnit unit) Associates the value with the key in this cache.
default boolean	putIfAbsent(K key, V value, long duration, TimeUnit unit) Associates the value with the key in this cache if the specified key is not already associated with a value.
void	setExpiresAfter(K key, long duration, TimeUnit unit) Specifies that the entry should be automatically removed from the cache once the duration has elapsed.
Map<K,V>	youngest(int limit) Returns an unmodifiable snapshot Map view of the cache with ordered traversal.

Method Detail

getExpiresAfter

@Nonnull
OptionalLong getExpiresAfter(@Nonnull
                                      K key,
                                      @Nonnull
                                      TimeUnit unit)

Returns the duration until the entry should be automatically removed. The expiration policy determines when the entry's duration is reset.

Parameters:

key - the key for the entry being queried

unit - the unit that age is expressed in

Returns:

the duration if the entry is present in the cache

setExpiresAfter

void setExpiresAfter(@Nonnull
                     K key,
                     @Nonnegative
                     long duration,
                     @Nonnull
                     TimeUnit unit)

Specifies that the entry should be automatically removed from the cache once the duration has elapsed. The expiration policy determines when the entry's age is reset.

Parameters:

key - the key for the entry being set

duration - the length of time from now when the entry should be automatically removed

unit - the unit that duration is expressed in

Throws:

IllegalArgumentException - if duration is negative

NullPointerException - if the unit is null

putIfAbsent

default boolean putIfAbsent(@Nonnull
                            K key,
                            @Nonnull
                            V value,
                            @Nonnegative
                            long duration,
                            @Nonnull
                            TimeUnit unit)

Associates the value with the key in this cache if the specified key is not already associated with a value. This method differs from Map.putIfAbsent(K, V) by substituting the configured Expiry with the specified write duration, has no effect on the duration if the entry was present, and returns the success rather than a value.

Parameters:

key - the key with which the specified value is to be associated

value - value to be associated with the specified key

duration - the length of time from now when the entry should be automatically removed

unit - the unit that duration is expressed in

Returns:

true if this cache did not already contain the specified entry

Throws:

IllegalArgumentException - if duration is negative

NullPointerException - if the specified key or value is null

put

default void put(@Nonnull
                 K key,
                 @Nonnull
                 V value,
                 @Nonnegative
                 long duration,
                 @Nonnull
                 TimeUnit unit)

Associates the value with the key in this cache. If the cache previously contained a value associated with the key, the old value is replaced by the new value. This method differs from Cache.put(K, V) by substituting the configured Expiry with the specified write duration.

Parameters:

key - the key with which the specified value is to be associated

value - value to be associated with the specified key

duration - the length of time from now when the entry should be automatically removed

unit - the unit that duration is expressed in

Throws:

IllegalArgumentException - if duration is negative

NullPointerException - if the specified key or value is null

oldest

@Nonnull
Map<K,V> oldest(@Nonnegative
                         int limit)

Returns an unmodifiable snapshot Map view of the cache with ordered traversal. The order of iteration is from the entries most likely to expire (oldest) to the entries least likely to expire (youngest). This order is determined by the expiration policy's best guess at the time of creating this snapshot view.

Beware that obtaining the mappings is NOT a constant-time operation. Because of the asynchronous nature of the page replacement policy, determining the retention ordering requires a traversal of the entries.

Parameters:

limit - the maximum size of the returned map (use Integer.MAX_VALUE to disregard the limit)

Returns:

a snapshot view of the cache from oldest entry to the youngest

youngest

@Nonnull
Map<K,V> youngest(@Nonnegative
                           int limit)

Returns an unmodifiable snapshot Map view of the cache with ordered traversal. The order of iteration is from the entries least likely to expire (youngest) to the entries most likely to expire (oldest). This order is determined by the expiration policy's best guess at the time of creating this snapshot view.

Beware that obtaining the mappings is NOT a constant-time operation. Because of the asynchronous nature of the page replacement policy, determining the retention ordering requires a traversal of the entries.

Parameters:

limit - the maximum size of the returned map (use Integer.MAX_VALUE to disregard the limit)

Returns:

a snapshot view of the cache from youngest entry to the oldest