CacheDispatcher.java revision d56b88ae161057e848e7410d1b9ce5b0b8c427fc
1d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru/* 2d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Copyright (C) 2011 The Android Open Source Project 3d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * 4d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Licensed under the Apache License, Version 2.0 (the "License"); 5d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * you may not use this file except in compliance with the License. 6d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * You may obtain a copy of the License at 7d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * 8d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * http://www.apache.org/licenses/LICENSE-2.0 9d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * 10d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Unless required by applicable law or agreed to in writing, software 11d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * distributed under the License is distributed on an "AS IS" BASIS, 12d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * See the License for the specific language governing permissions and 14d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * limitations under the License. 15d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru */ 16d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 17d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Querupackage com.android.volley; 18d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 19d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queruimport java.util.concurrent.BlockingQueue; 20d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 21d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru/** 22d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Provides a thread for performing cache triage on a queue of requests. 23d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * 24d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Requests added to the specified cache queue are resolved from cache. 25d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Any deliverable response is posted back to the caller via a 26d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * {@link ResponseDelivery}. Cache misses and responses that require 27d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * refresh are enqueued on the specified network queue for processing 28d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * by a {@link NetworkDispatcher}. 29d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru */ 30d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru@SuppressWarnings("rawtypes") 31d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Querupublic class CacheDispatcher extends Thread { 32d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 33d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private static final boolean DEBUG = VolleyLog.DEBUG; 34d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 35d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** The queue of requests coming in for triage. */ 36d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private final BlockingQueue<Request> mCacheQueue; 37d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 38d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** The queue of requests going out to the network. */ 39d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private final BlockingQueue<Request> mNetworkQueue; 40d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 41d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** The cache to read from. */ 42d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private final Cache mCache; 43d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 44d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** For posting responses. */ 45d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private final ResponseDelivery mDelivery; 46d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 47d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** Used for telling us to die. */ 48d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private volatile boolean mQuit = false; 49d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 50d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** 51d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Creates a new cache triage dispatcher thread. You must call {@link #start()} 52d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * in order to begin processing. 53d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * 54d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param cacheQueue Queue of incoming requests for triage 55d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param networkQueue Queue to post requests that require network to 56d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param cache Cache interface to use for resolution 57d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param delivery Delivery interface to use for posting responses 58d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru */ 59d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public CacheDispatcher( 60d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru BlockingQueue<Request> cacheQueue, BlockingQueue<Request> networkQueue, 61d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru Cache cache, ResponseDelivery delivery) { 62d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mCacheQueue = cacheQueue; 63d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue = networkQueue; 64d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mCache = cache; 65d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mDelivery = delivery; 66d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 67d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 68d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** 69d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Forces this dispatcher to quit immediately. If any requests are still in 70d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * the queue, they are not guaranteed to be processed. 71d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru */ 72d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public void quit() { 73d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mQuit = true; 74d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru interrupt(); 75d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 76d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 77d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru @Override 78d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public void run() { 79d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (DEBUG) VolleyLog.v("start new dispatcher"); 80d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 81d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Make a blocking call to initialize the cache. 82d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mCache.initialize(); 83d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 84d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru while (true) { 85d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru try { 86d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Get a request from the cache triage queue, blocking until 87d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // at least one is available. 88d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru final Request request = mCacheQueue.take(); 89d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-queue-take"); 90d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 91d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // If the request has been canceled, don't bother dispatching it. 92d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (request.isCanceled()) { 93d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.finish("cache-discard-canceled"); 94d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 95d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 96d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 97d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Attempt to retrieve this item from cache. 98d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru Cache.Entry entry = mCache.get(request.getCacheKey()); 99d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (entry == null) { 100d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-miss"); 101d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Cache miss; send off to the network dispatcher. 102d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue.put(request); 103d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 104d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 105d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 106d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // If it is completely expired, just send it to the network. 107d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (entry.isExpired()) { 108d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit-expired"); 109d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.setCacheEntry(entry); 110d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue.put(request); 111d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 112d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 113d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 114d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // We have a cache hit; parse its data for delivery back to the request. 115d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit"); 116d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru Response<?> response = request.parseNetworkResponse( 117d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru new NetworkResponse(entry.data)); 118d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit-parsed"); 119d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 120d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (!entry.refreshNeeded()) { 121d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Completely unexpired cache hit. Just deliver the response. 122d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mDelivery.postResponse(request, response); 123d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } else { 124d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Soft-expired cache hit. We can deliver the cached response, 125d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // but we need to also send the request to the network for 126d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // refreshing. 127d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit-refresh-needed"); 128d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.setCacheEntry(entry); 129d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 130d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Mark the response as intermediate. 131d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru response.intermediate = true; 132d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 133d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Post the intermediate response back to the user and have 134d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // the delivery then forward the request along to the network. 135d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mDelivery.postResponse(request, response, new Runnable() { 136d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru @Override 137d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public void run() { 138d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru try { 139d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue.put(request); 140d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } catch (InterruptedException e) { 141d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Not much we can do about this. 142d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 143d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 144d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru }); 145d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 146d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 147d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } catch (InterruptedException e) { 148d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // We may have been interrupted because it was time to quit. 149d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (mQuit) { 150d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru return; 151d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 152d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 153d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 154d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 155d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 156d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru} 157