1 /*
2  * Copyright (C) 2022 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.adservices.service.common.cache;
18 
19 import java.net.URL;
20 import java.util.List;
21 import java.util.Map;
22 
23 /** Interface for generic cache */
24 public interface HttpCache {
25 
26     /** Gets a cached entry */
get(URL url)27     DBCacheEntry get(URL url);
28 
29     /**
30      * Saves a cache entry
31      *
32      * @param url for which the request was made
33      * @param body response for the url
34      * @param requestPropertiesMap original connection's properties
35      */
put( URL url, String body, Map<String, List<String>> requestPropertiesMap, Map<String, List<String>> responseHeaders)36     void put(
37             URL url,
38             String body,
39             Map<String, List<String>> requestPropertiesMap,
40             Map<String, List<String>> responseHeaders);
41 
42     /** @return no of entries cached */
getCachedEntriesCount()43     long getCachedEntriesCount();
44 
45     /** @return no of entries taken from cache, saving network call */
getHitCount()46     long getHitCount();
47 
48     /** @return no of cache look-ups attempts made */
getRequestCount()49     long getRequestCount();
50 
51     /** Delete the cache */
delete()52     void delete();
53 
54     /** Clean up the cache */
cleanUp()55     void cleanUp();
56 
57     /** Possible observable events for Cache */
58     enum CacheEventType {
59         GET,
60         PUT,
61         DELETE,
62         CLEANUP
63     }
64 
65     /**
66      * Add observers to observe this cache's events
67      *
68      * @param observer that gets updated on events
69      */
addObserver(CacheObserver observer)70     void addObserver(CacheObserver observer);
71 
72     /**
73      * Notify all the registered observers
74      *
75      * @param cacheEvent type of caching event
76      */
notifyObservers(CacheEventType cacheEvent)77     void notifyObservers(CacheEventType cacheEvent);
78 
79     /** An observer that can help get updates from inside the cache events */
80     interface CacheObserver {
update(CacheEventType cacheEvent)81         void update(CacheEventType cacheEvent);
82     }
83 }
84