import 'package:angel_framework/angel_framework.dart';
import 'package:meta/meta.dart';

/// An Angel [Service] that caches data from another service.
///
/// This is useful for applications of scale, where network latency
/// can have real implications on application performance.
class CacheService extends Service {
  /// The underlying [Service] that represents the original data store.
  final Service database;

  /// The [Service] used to interface with a caching layer.
  ///
  /// If not provided, this defaults to a [MapService].
  final Service cache;

  CacheService({@required this.database, Service cache})
      : this.cache = cache ?? new MapService() {
    assert(database != null);
  }
}