Package org.openhab.core.cache

Class ExpiringCacheMap<K,V>

java.lang.Object
org.openhab.core.cache.ExpiringCacheMap<K,V>
Type Parameters:
K - the type of the key
V - the type of the value
@NonNullByDefault public class ExpiringCacheMap<K,V> extends Object
This is a simple expiring and reloading multiple key-value-pair cache implementation. The value expires after the specified duration has passed since the item was created, or the most recent replacement of the value.
Author:
Christoph Weitkamp - Initial contribution, Martin van Wingerden - Added constructor accepting Duration and putIfAbsentAndGet

  • Constructor Details

    • ExpiringCacheMap

      public ExpiringCacheMap(Duration expiry)
      Creates a new instance.
      Parameters:
      expiry - the duration for how long the value stays valid

    • ExpiringCacheMap

      public ExpiringCacheMap(long expiry)
      Creates a new instance.
      Parameters:
      expiry - the duration in milliseconds for how long the value stays valid

  • Method Details

    • put

      public void put(K key, Supplier<@Nullable V> action)
      Creates an ExpiringCache and adds it to the cache.
      Parameters:
      key - the key with which the specified value is to be associated
      action - the action for the item to be associated with the specified key to retrieve/calculate the value

    • put

      public void put(K key, ExpiringCache<@Nullable V> item)
      Adds an ExpiringCache to the cache.
      Parameters:
      key - the key with which the specified value is to be associated
      item - the item to be associated with the specified key

    • putIfAbsent

      public void putIfAbsent(K key, ExpiringCache<V> item)
      If the specified key is not already associated with a value, associate it with the given ExpiringCache.
      Parameters:
      key - the key with which the specified value is to be associated
      item - the item to be associated with the specified key

    • putIfAbsentAndGet

      public @Nullable V putIfAbsentAndGet(K key, Supplier<V> action)
      If the specified key is not already associated, associate it with the given action. Note that this method has the overhead of actually calling/performing the action
      Parameters:
      key - the key with which the specified value is to be associated
      action - the action for the item to be associated with the specified key to retrieve/calculate the value
      Returns:
      the (cached) value for the specified key

    • putIfAbsentAndGet

      public @Nullable V putIfAbsentAndGet(K key, ExpiringCache<V> item)
      If the specified key is not already associated with a value, associate it with the given ExpiringCache. Note that this method has the overhead of actually calling/performing the action
      Parameters:
      key - the key with which the specified value is to be associated
      item - the item to be associated with the specified key
      Returns:
      the (cached) value for the specified key

    • putValue

      public void putValue(K key, @Nullable V value)
      Puts a new value into the cache if the specified key is present.
      Parameters:
      key - the key whose value in the cache is to be updated
      value - the new value

    • containsKey

      public boolean containsKey(K key)
      Checks if the key is present in the cache.
      Parameters:
      key - the key whose presence in the cache is to be tested
      Returns:
      true if the cache contains a value for the specified key

    • remove

      public void remove(K key)
      Removes the item associated with the given key from the cache.
      Parameters:
      key - the key whose associated value is to be removed

    • clear

      public void clear()
      Discards all items from the cache.

    • keys

      public Set<K> keys()
      Returns a set of all keys.
      Returns:
      the set of all keys

    • get

      public @Nullable V get(K key)
      Returns the value associated with the given key - possibly from the cache, if it is still valid.
      Parameters:
      key - the key whose associated value is to be returned
      Returns:
      the value associated with the given key, or null if there is no cached value for the given key

    • values

      public Collection<@Nullable V> values()
      Returns a collection of all values - possibly from the cache, if they are still valid.
      Returns:
      the collection of all values

    • invalidate

      public void invalidate(K key)
      Invalidates the value associated with the given key in the cache.
      Parameters:
      key - the key whose associated value is to be invalidated

    • invalidateAll

      public void invalidateAll()
      Invalidates all values in the cache.

    • refresh

      public @Nullable V refresh(K key)
      Refreshes and returns the value associated with the given key in the cache.
      Parameters:
      key - the key whose associated value is to be refreshed
      Returns:
      the value associated with the given key, or null if there is no cached value for the given key

    • refreshAll

      public Collection<@Nullable V> refreshAll()
      Refreshes and returns a collection of all new values in the cache.
      Returns:
      the collection of all values