# Package org.apache.storm.windowing.persistence

- Interface Summary
  Interface | Description
  --- | ---
  WindowPartitionCache<K,​V> | A loading cache abstraction for caching `WindowState.WindowPartition`.
  WindowPartitionCache.Builder<K,​V> | Builder interface for `WindowPartitionCache`.
  WindowPartitionCache.CacheLoader<K,​V> | The interface for loading entires into the cache.
  WindowPartitionCache.RemovalListener<K,​V> | A callback interface for handling removal of events from the cache.

- Class Summary
  Class | Description
  --- | ---
  SimpleWindowPartitionCache<K,​V> | A simple implementation that evicts the largest un-pinned entry from the cache.
  SimpleWindowPartitionCache.SimpleWindowPartitionCacheBuilder<K,​V> |
  WindowState<T> | A wrapper around the window related states that are checkpointed.
  WindowState.WindowPartition<T> |

- Enum Summary
  Enum | Description
  --- | ---
  WindowPartitionCache.RemovalCause | The reason why an enrty got evicted from the cache.