CacheDispatcher.java revision 35d5cc345a7bc5c7391aeda3d3fce711c6376c7b
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 196772bce3d3322ccbcf6481545ffe895d5d401b39Jean-Baptiste Queruimport android.os.Process; 206772bce3d3322ccbcf6481545ffe895d5d401b39Jean-Baptiste Queru 21d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queruimport java.util.concurrent.BlockingQueue; 22d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 23d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru/** 24d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Provides a thread for performing cache triage on a queue of requests. 25d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * 26d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Requests added to the specified cache queue are resolved from cache. 27d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Any deliverable response is posted back to the caller via a 28d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * {@link ResponseDelivery}. Cache misses and responses that require 29d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * refresh are enqueued on the specified network queue for processing 30d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * by a {@link NetworkDispatcher}. 31d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru */ 32d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Querupublic class CacheDispatcher extends Thread { 33d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 34d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private static final boolean DEBUG = VolleyLog.DEBUG; 35d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 36d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** The queue of requests coming in for triage. */ 3735d5cc345a7bc5c7391aeda3d3fce711c6376c7bFicus Kirkpatrick private final BlockingQueue<Request<?>> mCacheQueue; 38d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 39d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** The queue of requests going out to the network. */ 4035d5cc345a7bc5c7391aeda3d3fce711c6376c7bFicus Kirkpatrick private final BlockingQueue<Request<?>> mNetworkQueue; 41d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 42d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** The cache to read from. */ 43d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private final Cache mCache; 44d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 45d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** For posting responses. */ 46d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private final ResponseDelivery mDelivery; 47d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 48d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** Used for telling us to die. */ 49d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru private volatile boolean mQuit = false; 50d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 51d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** 52d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Creates a new cache triage dispatcher thread. You must call {@link #start()} 53d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * in order to begin processing. 54d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * 55d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param cacheQueue Queue of incoming requests for triage 56d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param networkQueue Queue to post requests that require network to 57d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param cache Cache interface to use for resolution 58d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * @param delivery Delivery interface to use for posting responses 59d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru */ 60d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public CacheDispatcher( 6135d5cc345a7bc5c7391aeda3d3fce711c6376c7bFicus Kirkpatrick BlockingQueue<Request<?>> cacheQueue, BlockingQueue<Request<?>> networkQueue, 62d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru Cache cache, ResponseDelivery delivery) { 63d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mCacheQueue = cacheQueue; 64d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue = networkQueue; 65d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mCache = cache; 66d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mDelivery = delivery; 67d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 68d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 69d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru /** 70d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * Forces this dispatcher to quit immediately. If any requests are still in 71d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru * the queue, they are not guaranteed to be processed. 72d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru */ 73d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public void quit() { 74d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mQuit = true; 75d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru interrupt(); 76d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 77d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 78d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru @Override 79d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public void run() { 80d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (DEBUG) VolleyLog.v("start new dispatcher"); 816772bce3d3322ccbcf6481545ffe895d5d401b39Jean-Baptiste Queru Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); 82d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 83d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Make a blocking call to initialize the cache. 84d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mCache.initialize(); 85d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 86d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru while (true) { 87d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru try { 88d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Get a request from the cache triage queue, blocking until 89d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // at least one is available. 9035d5cc345a7bc5c7391aeda3d3fce711c6376c7bFicus Kirkpatrick final Request<?> request = mCacheQueue.take(); 91d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-queue-take"); 92d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 93d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // If the request has been canceled, don't bother dispatching it. 94d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (request.isCanceled()) { 95d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.finish("cache-discard-canceled"); 96d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 97d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 98d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 99d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Attempt to retrieve this item from cache. 100d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru Cache.Entry entry = mCache.get(request.getCacheKey()); 101d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (entry == null) { 102d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-miss"); 103d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Cache miss; send off to the network dispatcher. 104d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue.put(request); 105d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 106d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 107d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 108d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // If it is completely expired, just send it to the network. 109d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (entry.isExpired()) { 110d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit-expired"); 111d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.setCacheEntry(entry); 112d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue.put(request); 113d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 114d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 115d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 116d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // We have a cache hit; parse its data for delivery back to the request. 117d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit"); 118d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru Response<?> response = request.parseNetworkResponse( 119e48f4430bfd3030350aa5ba827b449c37e2fadc9Jean-Baptiste Queru new NetworkResponse(entry.data, entry.responseHeaders)); 120d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit-parsed"); 121d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 122d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (!entry.refreshNeeded()) { 123d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Completely unexpired cache hit. Just deliver the response. 124d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mDelivery.postResponse(request, response); 125d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } else { 126d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Soft-expired cache hit. We can deliver the cached response, 127d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // but we need to also send the request to the network for 128d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // refreshing. 129d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.addMarker("cache-hit-refresh-needed"); 130d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru request.setCacheEntry(entry); 131d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 132d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Mark the response as intermediate. 133d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru response.intermediate = true; 134d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 135d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Post the intermediate response back to the user and have 136d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // the delivery then forward the request along to the network. 137d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mDelivery.postResponse(request, response, new Runnable() { 138d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru @Override 139d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru public void run() { 140d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru try { 141d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru mNetworkQueue.put(request); 142d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } catch (InterruptedException e) { 143d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // Not much we can do about this. 144d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 145d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 146d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru }); 147d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 148d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru 149d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } catch (InterruptedException e) { 150d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru // We may have been interrupted because it was time to quit. 151d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru if (mQuit) { 152d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru return; 153d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 154d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru continue; 155d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 156d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 157d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru } 158d56b88ae161057e848e7410d1b9ce5b0b8c427fcJean-Baptiste Queru} 159