Weak Cache #

Weak cache is a Map implementation that uses WeakReferences for holding values and Finalizer to manage it's storage.

You can use it to cache data (e.g. API responses) for a small amount of time (until next garbage collection cycle).

Features #

• Uses WeakReference for storing values.
• Uses Finalizer to remove objects from internal storage upon their deletion.
• Allows you iterate over keys/values.

  While iterating, all stored values are temporarily made into strong references, to prevent concurrent edit of storage, while iterating over it.

• Optimized containsValue via internal managed Expando.
• Implements full Map<K, V> interface.
• WeakCache itself can be safely garbage collected and doesn't hold unto any stored.

Usage #

Just create cache, add some values, and they'll be removed when all other strong references to they are lost.

// ID - Object cache
final cache = WeakCache<int, Object>();

Object? obj = Object();
cache[0] = obj;
// ...
obj = null;
// ...
// After garbage collection cache[0] will be removed.
cache[0] == null;

See example for detailed test case.