提交项目

app/src/main/java/com/android/volley/NetworkDispatcher.java

@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * 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.
+ */
+
+package com.android.volley;
+
+import java.util.concurrent.BlockingQueue;
+
+import android.net.TrafficStats;
+import android.os.Build;
+import android.os.Process;
+
+/**
+ * Provides a thread for performing network dispatch from a queue of requests.
+ *
+ * Requests added to the specified queue are processed from the network via a
+ * specified {@link Network} interface. Responses are committed to cache, if
+ * eligible, using a specified {@link Cache} interface. Valid responses and
+ * errors are posted back to the caller via a {@link ResponseDelivery}.
+ */
+@SuppressWarnings("rawtypes")
+public class NetworkDispatcher extends Thread {
+    /** The queue of requests to service. */
+    private final BlockingQueue<Request> mQueue;
+    /** The network interface for processing requests. */
+    private final Network mNetwork;
+    /** The cache to write to. */
+    private final Cache mCache;
+    /** For posting responses and errors. */
+    private final ResponseDelivery mDelivery;
+    /** Used for telling us to die. */
+    private volatile boolean mQuit = false;
+
+    /**
+     * Creates a new network dispatcher thread.  You must call {@link #start()}
+     * in order to begin processing.
+     *
+     * @param queue Queue of incoming requests for triage
+     * @param network Network interface to use for performing requests
+     * @param cache Cache interface to use for writing responses to cache
+     * @param delivery Delivery interface to use for posting responses
+     */
+    public NetworkDispatcher(BlockingQueue<Request> queue,
+            Network network, Cache cache,
+            ResponseDelivery delivery) {
+        mQueue = queue;
+        mNetwork = network;
+        mCache = cache;
+        mDelivery = delivery;
+    }
+
+    /**
+     * Forces this dispatcher to quit immediately.  If any requests are still in
+     * the queue, they are not guaranteed to be processed.
+     */
+    public void quit() {
+        mQuit = true;
+        interrupt();
+    }
+
+    @Override
+    public void run() {
+        Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
+        Request request;
+        while (true) {
+            try {
+                // Take a request from the queue.
+                request = mQueue.take();
+            } catch (InterruptedException e) {
+                // We may have been interrupted because it was time to quit.
+                if (mQuit) {
+                    return;
+                }
+                continue;
+            }
+
+            try {
+                request.addMarker("network-queue-take");
+
+                // If the request was cancelled already, do not perform the
+                // network request.
+                if (request.isCanceled()) {
+                    request.finish("network-discard-cancelled");
+                    continue;
+                }
+
+                // Tag the request (if API >= 14)
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
+                    TrafficStats.setThreadStatsTag(request.getTrafficStatsTag());
+                }
+
+                // Perform the network request.
+                NetworkResponse networkResponse = mNetwork.performRequest(request);
+                request.addMarker("network-http-complete");
+
+                // If the server returned 304 AND we delivered a response already,
+                // we're done -- don't deliver a second identical response.
+                if (networkResponse.notModified && request.hasHadResponseDelivered()) {
+                    request.finish("not-modified");
+                    continue;
+                }
+
+                // Parse the response here on the worker thread.
+                Response<?> response = request.parseNetworkResponse(networkResponse);
+                request.addMarker("network-parse-complete");
+
+                // Write to cache if applicable.
+                // TODO: Only update cache metadata instead of entire record for 304s.
+                if (request.shouldCache() && response.cacheEntry != null) {
+                    mCache.put(request.getCacheKey(), response.cacheEntry);
+                    request.addMarker("network-cache-written");
+                }
+
+                // Post the response back.
+                request.markDelivered();
+                mDelivery.postResponse(request, response);
+            } catch (VolleyError volleyError) {
+                parseAndDeliverNetworkError(request, volleyError);
+            } catch (Exception e) {
+                VolleyLog.e(e, "Unhandled exception %s", e.toString());
+                mDelivery.postError(request, new VolleyError(e));
+            }
+        }
+    }
+
+    private void parseAndDeliverNetworkError(Request<?> request, VolleyError error) {
+        error = request.parseNetworkError(error);
+        mDelivery.postError(request, error);
+    }
+}