Commit bf68646

@@ -0,0 +1,21 @@
+import 'dart:collection';
+
+import 'package:health_data_store/health_data_store.dart';
+
+/// A data provider provides access to the data.
+///
+/// It interacts with the databases on a low level and only supports basic CRUD
+/// operations.
+///
+/// Tables are structured in a way that they have a id ([int]) as a primary
+/// key and have one or more other columns associated with that key.
+abstract class DataProvider<T> {
+  /// Gets all entries in the inclusive range.
+  Future<UnmodifiableListView<(int,T)>> getInRange(DateRange range);
+
+  /// Sets the data at [entryID] to [value].
+  Future<void> set(int entryID, T value);
+
+  /// Removes the value associated with this [entryID].
+  Future<void> remove(int entryID);
+}

@@ -0,0 +1,22 @@
+import 'dart:collection';
+
+import 'package:health_data_store/src/data_providers/data_provider.dart';
+import 'package:health_data_store/src/types/date_range.dart';
+
+/// A repository is a abstraction around multiple [DataProvider]s.
+///
+/// Repositories wrap the primitive values of [DataProvider]s into more complex
+/// types and provides domain models for the application.
+abstract class Repository<T> {
+  /// Adds a new value to the repository.
+  Future<void> add(T value);
+
+  /// Attempts to remove a value from the repository.
+  ///
+  /// This should only be called for values for values that are known to be in
+  /// the repository.
+  Future<void> remove(T value);
+
+  /// Inclusively returns all values in the specified [range].
+  Future<UnmodifiableListView<T>> get(DateRange range);
+}