Module com.github.benmanes.caffeine
Package 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

      All Methods Instance Methods Abstract Methods Default Methods 
      Modifier and Type Method Description
      default @PolyNull V compute​(K key, BiFunction<? super K,​? super V,​? extends @PolyNull V> remappingFunction, Duration duration)
      Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).
      default Optional<Duration> getExpiresAfter​(K key)
      Returns the duration until the entry should be automatically removed.
      OptionalLong getExpiresAfter​(K key, TimeUnit unit)
      Returns the duration until the entry should be automatically removed.
      Map<K,​V> oldest​(@org.checkerframework.checker.index.qual.NonNegative int limit)
      Returns an unmodifiable snapshot Map view of the cache with ordered traversal.
      default <T> T oldest​(Function<Stream<Policy.CacheEntry<K,​V>>,​T> mappingFunction)
      Returns the computed result from the ordered traversal of the cache entries.
      @Nullable V put​(K key, V value, @org.checkerframework.checker.index.qual.NonNegative long duration, TimeUnit unit)
      Associates the value with the key in this cache.
      default @Nullable V put​(K key, V value, Duration duration)
      Associates the value with the key in this cache.
      @Nullable V putIfAbsent​(K key, V value, @org.checkerframework.checker.index.qual.NonNegative long duration, TimeUnit unit)
      Associates the value with the key in this cache if the specified key is not already associated with a value.
      default @Nullable V putIfAbsent​(K key, V value, Duration duration)
      Associates the value with the key in this cache if the specified key is not already associated with a value.
      void setExpiresAfter​(K key, @org.checkerframework.checker.index.qual.NonNegative long duration, TimeUnit unit)
      Specifies that the entry should be automatically removed from the cache once the duration has elapsed.
      default void setExpiresAfter​(K key, Duration duration)
      Specifies that the entry should be automatically removed from the cache once the duration has elapsed.
      Map<K,​V> youngest​(@org.checkerframework.checker.index.qual.NonNegative int limit)
      Returns an unmodifiable snapshot Map view of the cache with ordered traversal.
      default <T> T youngest​(Function<Stream<Policy.CacheEntry<K,​V>>,​T> mappingFunction)
      Returns the computed result from the ordered traversal of the cache entries.

    • Method Detail

      • getExpiresAfter

        OptionalLong getExpiresAfter​(K key,
                             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
        Throws:
        NullPointerException - if the specified key or unit is null

      • getExpiresAfter

        default Optional<Duration> getExpiresAfter​(K key)
        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
        Returns:
        the duration if the entry is present in the cache
        Throws:
        NullPointerException - if the specified key is null

      • setExpiresAfter

        void setExpiresAfter​(K key,
                     @org.checkerframework.checker.index.qual.NonNegative long duration,
                     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 specified key or unit is null

      • setExpiresAfter

        default void setExpiresAfter​(K key,
                             Duration duration)
        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
        Throws:
        IllegalArgumentException - if duration is negative
        NullPointerException - if the specified key or duration is null

      • putIfAbsent

        @Nullable V putIfAbsent​(K key,
                        V value,
                        @org.checkerframework.checker.index.qual.NonNegative long duration,
                        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 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:
        the previous value associated with the specified key, or null if there was no mapping for the key.
        Throws:
        IllegalArgumentException - if duration is negative
        NullPointerException - if the specified key, value, or unit is null

      • putIfAbsent

        default @Nullable V putIfAbsent​(K key,
                                V value,
                                Duration duration)
        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 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
        Returns:
        the previous value associated with the specified key, or null if there was no mapping for the key.
        Throws:
        IllegalArgumentException - if duration is negative
        NullPointerException - if the specified key, value, or duration is null

      • put

        @Nullable V put​(K key,
                V value,
                @org.checkerframework.checker.index.qual.NonNegative long duration,
                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 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
        Returns:
        the previous value associated with key, or null if there was no mapping for key.
        Throws:
        IllegalArgumentException - if duration is negative
        NullPointerException - if the specified key, value, or unit is null

      • put

        default @Nullable V put​(K key,
                        V value,
                        Duration duration)
        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 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
        Returns:
        the previous value associated with key, or null if there was no mapping for key.
        Throws:
        IllegalArgumentException - if duration is negative
        NullPointerException - if the specified key, value, or duration is null

      • compute

        default @PolyNull V compute​(K key,
                            BiFunction<? super K,​? super V,​? extends @PolyNull V> remappingFunction,
                            Duration duration)
        Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). The entire method invocation is performed atomically. The supplied function is invoked exactly once per invocation of this method. Some attempted update operations on this cache by other threads may be blocked while the computation is in progress, so the computation should be short and simple. This method differs from cache.asMap().compute(key, remappingFunction) by substituting the configured Expiry with the specified duration.

        Warning: the remappingFunction must not attempt to update any other mappings of this cache.

        Parameters:
        key - key with which the specified value is to be associated
        remappingFunction - the function to compute a value
        duration - the length of time from now when the entry should be automatically removed
        Returns:
        the new value associated with the specified key, or null if none
        Throws:
        IllegalArgumentException - if duration is negative
        NullPointerException - if the specified key, remappingFunction, or duration is null
        IllegalStateException - if the computation detectably attempts a recursive update to this cache that would otherwise never complete
        RuntimeException - or Error if the remappingFunction does so, in which case the mapping is unchanged

      • oldest

        Map<K,​V> oldest​(@org.checkerframework.checker.index.qual.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 the oldest entry to the youngest

      • oldest

        default <T> T oldest​(Function<Stream<Policy.CacheEntry<K,​V>>,​T> mappingFunction)
        Returns the computed result from the ordered traversal of the cache entries. The oorder 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 computation.

        Usage example: 

        
   List<K> tenOldestKeys = cache.policy().expireAfterVariably().orElseThrow()
       .oldest(stream -> stream.map(Map.Entry::getKey).limit(10).toList());

        Beware that this computation is performed within the eviction policy's exclusive lock, so the computation should be short and simple. While the computation is in progress further eviction maintenance will be halted.

        Type Parameters:
        T - the type of the result of the mappingFunction
        Parameters:
        mappingFunction - the mapping function to compute a value
        Returns:
        the computed value
        Throws:
        NullPointerException - if the mappingFunction is null
        RuntimeException - or Error if the mappingFunction does so

      • youngest

        Map<K,​V> youngest​(@org.checkerframework.checker.index.qual.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 the youngest entry to the oldest

      • youngest

        default <T> T youngest​(Function<Stream<Policy.CacheEntry<K,​V>>,​T> mappingFunction)
        Returns the computed result from the ordered traversal of the cache entries. 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 computation.

        Usage example: 

        
   List<K> tenYoungestKeys = cache.policy().expireAfterVariably().orElseThrow()
       .youngest(stream -> stream.map(Map.Entry::getKey).limit(10).toList());

        Beware that this computation is performed within the eviction policy's exclusive lock, so the computation should be short and simple. While the computation is in progress further eviction maintenance will be halted.

        Type Parameters:
        T - the type of the result of the mappingFunction
        Parameters:
        mappingFunction - the mapping function to compute a value
        Returns:
        the computed value
        Throws:
        NullPointerException - if the mappingFunction is null
        RuntimeException - or Error if the mappingFunction does so