Implement HostListManager by Refactoring HostListLoader

remoting/android/java/src/org/chromium/chromoting/HostListLoader.java

Index: remoting/android/java/src/org/chromium/chromoting/HostListLoader.java
diff --git a/remoting/android/java/src/org/chromium/chromoting/HostListLoader.java b/remoting/android/java/src/org/chromium/chromoting/HostListLoader.java
deleted file mode 100644
index a7e35905d51ffa80bd2a45383564ff409bbb4704..0000000000000000000000000000000000000000
--- a/remoting/android/java/src/org/chromium/chromoting/HostListLoader.java
+++ /dev/null
@@ -1,194 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.chromoting;
-
-import android.os.Handler;
-import android.os.HandlerThread;
-import android.os.Looper;
-
-import org.chromium.base.Log;
-import org.json.JSONArray;
-import org.json.JSONException;
-import org.json.JSONObject;
-
-import java.io.IOException;
-import java.net.HttpURLConnection;
-import java.net.MalformedURLException;
-import java.net.URL;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.Locale;
-import java.util.Scanner;
-
-/** Helper for fetching the host list. */
-public class HostListLoader {
-    public enum Error {
-        AUTH_FAILED,
-        NETWORK_ERROR,
-        SERVICE_UNAVAILABLE,
-        UNEXPECTED_RESPONSE,
-        UNKNOWN,
-    }
-
-    /** Callback for receiving the host list, or getting notified of an error. */
-    public interface Callback {
-        void onHostListReceived(HostInfo[] hosts);
-        void onError(Error error);
-    }
-
-    private static final String TAG = "Chromoting";
-
-    /** Path from which to download a user's host list JSON object. */
-    private static final String HOST_LIST_PATH =
-            "https://www.googleapis.com/chromoting/v1/@me/hosts";
-
-    /** Callback handler to be used for network operations. */
-    private Handler mNetworkThread;
-
-    /** Handler for main thread. */
-    private Handler mMainThread;
-
-    public HostListLoader() {
-        // Thread responsible for downloading the host list.
-
-        mMainThread = new Handler(Looper.getMainLooper());
-    }
-
-    private void initNetworkThread() {
-        if (mNetworkThread == null) {
-            HandlerThread thread = new HandlerThread("network");
-            thread.start();
-            mNetworkThread = new Handler(thread.getLooper());
-        }
-    }
-
-    /**
-      * Causes the host list to be fetched on a background thread. This should be called on the
-      * main thread, and callbacks will also be invoked on the main thread. On success,
-      * callback.onHostListReceived() will be called, otherwise callback.onError() will be called
-      * with an error-code describing the failure.
-      */
-    public void retrieveHostList(String authToken, Callback callback) {
-        initNetworkThread();
-        final String authTokenFinal = authToken;
-        final Callback callbackFinal = callback;
-        mNetworkThread.post(new Runnable() {
-            @Override
-            public void run() {
-                doRetrieveHostList(authTokenFinal, callbackFinal);
-            }
-        });
-    }
-
-    private void doRetrieveHostList(String authToken, Callback callback) {
-        HttpURLConnection link = null;
-        String response = null;
-        try {
-            link = (HttpURLConnection) new URL(HOST_LIST_PATH).openConnection();
-            link.setRequestProperty("Authorization", "OAuth " + authToken);
-
-            // Listen for the server to respond.
-            int status = link.getResponseCode();
-            switch (status) {
-                case HttpURLConnection.HTTP_OK:  // 200
-                    break;
-                case HttpURLConnection.HTTP_UNAUTHORIZED:  // 401
-                    postError(callback, Error.AUTH_FAILED);
-                    return;
-                case HttpURLConnection.HTTP_BAD_GATEWAY:  // 502
-                case HttpURLConnection.HTTP_UNAVAILABLE:  // 503
-                    postError(callback, Error.SERVICE_UNAVAILABLE);
-                    return;
-                default:
-                    postError(callback, Error.UNKNOWN);
-                    return;
-            }
-
-            StringBuilder responseBuilder = new StringBuilder();
-            Scanner incoming = new Scanner(link.getInputStream());
-            while (incoming.hasNext()) {
-                responseBuilder.append(incoming.nextLine());
-            }
-            response = String.valueOf(responseBuilder);
-            incoming.close();
-        } catch (MalformedURLException ex) {
-            // This should never happen.
-            throw new RuntimeException("Unexpected error while fetching host list: ", ex);
-        } catch (IOException ex) {
-            postError(callback, Error.NETWORK_ERROR);
-            return;
-        } finally {
-            if (link != null) {
-                link.disconnect();
-            }
-        }
-
-        // Parse directory response.
-        ArrayList<HostInfo> hostList = new ArrayList<HostInfo>();
-        try {
-            JSONObject data = new JSONObject(response).getJSONObject("data");
-            if (data.has("items")) {
-                JSONArray hostsJson = data.getJSONArray("items");
-
-                int index = 0;
-                while (!hostsJson.isNull(index)) {
-                    JSONObject hostJson = hostsJson.getJSONObject(index);
-                    // If a host is only recently registered, it may be missing some of the keys
-                    // below. It should still be visible in the list, even though a connection
-                    // attempt will fail because of the missing keys. The failed attempt will
-                    // trigger reloading of the host-list, by which time the keys will hopefully be
-                    // present, and the retried connection can succeed.
-                    HostInfo host = HostInfo.create(hostJson);
-                    hostList.add(host);
-                    ++index;
-                }
-            }
-        } catch (JSONException ex) {
-            // Logging the exception stack trace may be too spammy.
-            Log.e(TAG, "Error parsing host list response: %s", ex.getMessage());
-            postError(callback, Error.UNEXPECTED_RESPONSE);
-            return;
-        }
-
-        sortHosts(hostList);
-
-        final Callback callbackFinal = callback;
-        final HostInfo[] hosts = hostList.toArray(new HostInfo[hostList.size()]);
-        mMainThread.post(new Runnable() {
-            @Override
-            public void run() {
-                callbackFinal.onHostListReceived(hosts);
-            }
-        });
-    }
-
-    /** Posts error to callback on main thread. */
-    private void postError(Callback callback, Error error) {
-        final Callback callbackFinal = callback;
-        final Error errorFinal = error;
-        mMainThread.post(new Runnable() {
-            @Override
-            public void run() {
-                callbackFinal.onError(errorFinal);
-            }
-        });
-    }
-
-    private static void sortHosts(ArrayList<HostInfo> hosts) {
-        Comparator<HostInfo> hostComparator = new Comparator<HostInfo>() {
-            @Override
-            public int compare(HostInfo a, HostInfo b) {
-                if (a.isOnline != b.isOnline) {
-                    return a.isOnline ? -1 : 1;
-                }
-                String aName = a.name.toUpperCase(Locale.getDefault());
-                String bName = b.name.toUpperCase(Locale.getDefault());
-                return aName.compareTo(bName);
-            }
-        };
-        Collections.sort(hosts, hostComparator);
-    }
-}