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quiver/lib/src/cache/cache.dart

-// Copyright 2013 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-part of quiver.cache;
-
-/**
- * A function that produces a value for [key], for when a [Cache] needs to
- * populate an entry.
- *
- * The loader function should either return a value synchronously or a [Future]
- * which completes with the value asynchronously.
- */
-typedef dynamic Loader<K>(K key);
-
-/**
- * A semi-persistent mapping of keys to values.
- *
- * All access to a Cache is asynchronous because many implementations will store
- * their entries in remote systems, isolates, or otherwise have to do async IO
- * to read and write.
- */
-abstract class Cache<K, V> {
-
-  /**
-   * Returns the value associated with [key].
-   */
-  Future<V> get(K key, {Loader<K> ifAbsent});
-
-  /**
-   * Sets the value associated with [key]. The Future completes with null when
-   * the operation is complete.
-   */
-  Future set(K key, V value);
-
-  /**
-   * Removes the value associated with [key]. The Future completes with null
-   * when the operation is complete.
-   */
-  Future invalidate(K key);
-}