Ecache
Ecache is a simple library to implement in-memory caching with support to remove entries.
It is inspired by gcache
Feature
- Supports expiration based on Least frequently used item (LFU)
- Supports expiration based on Least recently used items (LRU)
- Supports expiration based on removing the "first" entry in the list
- Supports for weakreference storages (minimum capacity is guaranteed, additional items may be removed by garbage collection when not needed)
- Supports expiration based on duration (expiration)
- Callback for items to perform cleanup (Optional)
Installation
Add to pubspec.yaml:
dependencies:
ecache: ^2.0.3
Simple use case
import 'package:ecache/ecache.dart';
void main() {
Cache c = SimpleCache(capacity: 20);
c.set("key", 42);
print(c.get("key")); // 42
print(c.containsKey("unknown_key")); // false
print(c.get("unknown_key")); // nil
}
Evict items
import 'package:ecache/ecache.dart';
void main() {
Cache c = SimpleCache(capacity: 20, storage: SimpleStorage(onEvict: (key, value) {
value.dispose();
}));
c.set("key", 42);
print(c.get("key")); // 42
print(c.containsKey("unknown_key")); // false
print(c.get("unknown_key")); // nil
print(c["key"]); // 42
c["halfKey"] = 21;
}
Get statistics
import 'package:ecache/ecache.dart';
void main() {
storage = StatisticsStorage();
Cache c = SimpleCache(storage: storage, capacity: 20);
c.set("key", 42);
print(c.get("key")); // 42
print(c.containsKey("unknown_key")); // false
print(c.get("unknown_key")); // nil
print(storage.toString());
}
Weak references
import 'package:ecache/ecache.dart';
void main() {
storage = WeakReferenceStorage();
Cache c = SimpleCache(storage: storage, capacity: 20);
}
In this example 20 items are guaranteed to remain in the cache. When adding more items the older ones will be moved to a weak reference cache. This cache can be removed by the garbage collection at any time.
So when retrieving such an item from cache it may or may not be returned from weakreference cache depending if the garbage collection had been run and evicted the items.
Note that we cannot guarantee to always call the evict-callback so do not use both eviction and weak reference at the same cache.
Author
Original Author: Kevin PLATEL
Author of ecache: Michael Schwartz.
License
MIT License, see LICENSE file