Refactor AsyncDownloader to be an interface.

The interface is used by both AsyncDownloadWrapper and
AsyncDownloaderFromAndroid.

F-Droid/src/org/fdroid/fdroid/net/AsyncDownloadWrapper.java

@@ -0,0 +1,98 @@
+package org.fdroid.fdroid.net;
+
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Message;
+import android.util.Log;
+
+import java.io.IOException;
+
+class AsyncDownloadWrapper extends Handler implements AsyncDownloader {
+
+    private static final String TAG = "AsyncDownloadWrapper";
+
+    private static final int MSG_DOWNLOAD_COMPLETE  = 2;
+    private static final int MSG_DOWNLOAD_CANCELLED = 3;
+    private static final int MSG_ERROR              = 4;
+    private static final String MSG_DATA            = "data";
+
+    private final Downloader downloader;
+    private DownloadThread downloadThread = null;
+
+    private final Listener listener;
+
+    /**
+     * Normally the listener would be provided using a setListener method.
+     * However for the purposes of this async downloader, it doesn't make
+     * sense to have an async task without any way to notify the outside
+     * world about completion. Therefore, we require the listener as a
+     * parameter to the constructor.
+     */
+    public AsyncDownloadWrapper(Downloader downloader, Listener listener) {
+        this.downloader = downloader;
+        this.listener = listener;
+    }
+
+    public int getBytesRead() {
+        return downloader.getBytesRead();
+    }
+
+    public int getTotalBytes() {
+        return downloader.getTotalBytes();
+    }
+
+    public void download() {
+        downloadThread = new DownloadThread();
+        downloadThread.start();
+    }
+
+    public void attemptCancel(boolean userRequested) {
+        if (downloadThread != null) {
+            downloadThread.interrupt();
+        }
+    }
+
+    /**
+     * Receives "messages" from the download thread, and passes them onto the
+     * relevant {@link AsyncDownloader.Listener}
+     */
+    public void handleMessage(Message message) {
+        switch (message.arg1) {
+            case MSG_DOWNLOAD_COMPLETE:
+                listener.onDownloadComplete();
+                break;
+            case MSG_DOWNLOAD_CANCELLED:
+                listener.onDownloadCancelled();
+                break;
+            case MSG_ERROR:
+                listener.onErrorDownloading(message.getData().getString(MSG_DATA));
+                break;
+        }
+    }
+
+    private class DownloadThread extends Thread {
+
+        public void run() {
+            try {
+                downloader.download();
+                sendMessage(MSG_DOWNLOAD_COMPLETE);
+            } catch (InterruptedException e) {
+                sendMessage(MSG_DOWNLOAD_CANCELLED);
+            } catch (IOException e) {
+                Log.e(TAG, "I/O exception in download thread", e);
+                Bundle data = new Bundle(1);
+                data.putString(MSG_DATA, e.getLocalizedMessage());
+                Message message = new Message();
+                message.arg1 = MSG_ERROR;
+                message.setData(data);
+                AsyncDownloadWrapper.this.sendMessage(message);
+            }
+        }
+
+        private void sendMessage(int messageType) {
+            Message message = new Message();
+            message.arg1 = messageType;
+            AsyncDownloadWrapper.this.sendMessage(message);
+        }
+    }
+}

F-Droid/src/org/fdroid/fdroid/net/AsyncDownloader.java

@@ -9,106 +9,17 @@ import org.fdroid.fdroid.ProgressListener;
 
 import java.io.IOException;
 
-/**
+public interface AsyncDownloader {
- * Given a {@link org.fdroid.fdroid.net.Downloader}, this wrapper will conduct the download operation on a
- * separate thread. All progress/status/error/etc events will be forwarded from that thread to the thread
- * that {@link AsyncDownloader#download()} was invoked on. If you want to respond with UI feedback
- * to these events, it is important that you execute the download method of this class from the UI thread.
- * That way, all forwarded events will be handled on that thread.
- */
-@SuppressWarnings("serial")
-public class AsyncDownloader extends Handler {
 
-    private static final String TAG = "AsyncDownloadWrapper";
+    interface Listener extends ProgressListener {
-
-    private static final int MSG_DOWNLOAD_COMPLETE  = 2;
-    private static final int MSG_DOWNLOAD_CANCELLED = 3;
-    private static final int MSG_ERROR              = 4;
-    private static final String MSG_DATA            = "data";
-
-    private final Downloader downloader;
-    private final Listener listener;
-    private DownloadThread downloadThread = null;
-
-    /**
-     * Normally the listener would be provided using a setListener method.
-     * However for the purposes of this async downloader, it doesn't make
-     * sense to have an async task without any way to notify the outside
-     * world about completion. Therefore, we require the listener as a
-     * parameter to the constructor.
-     */
-    public AsyncDownloader(Downloader downloader, Listener listener) {
-        this.downloader = downloader;
-        this.listener   = listener;
-    }
-
-    public void download() {
-        downloadThread = new DownloadThread();
-        downloadThread.start();
-    }
-
-    public void attemptCancel(boolean userRequested) {
-        if (downloadThread != null) {
-            downloadThread.interrupt();
-        }
-    }
-
-    /**
-     * Receives "messages" from the download thread, and passes them onto the
-     * relevant {@link AsyncDownloader.Listener}
-     * @param message
-     */
-    public void handleMessage(Message message) {
-        switch (message.arg1) {
-        case MSG_DOWNLOAD_COMPLETE:
-            listener.onDownloadComplete();
-            break;
-        case MSG_DOWNLOAD_CANCELLED:
-            listener.onDownloadCancelled();
-            break;
-        case MSG_ERROR:
-            listener.onErrorDownloading(message.getData().getString(MSG_DATA));
-            break;
-        }
-    }
-
-    public int getBytesRead() {
-        return downloader.getBytesRead();
-    }
-
-    public int getTotalBytes() {
-        return downloader.getTotalBytes();
-    }
-
-    public interface Listener extends ProgressListener {
         void onErrorDownloading(String localisedExceptionDetails);
         void onDownloadComplete();
         void onDownloadCancelled();
     }
 
-    private class DownloadThread extends Thread {
+    int getBytesRead();
+    int getTotalBytes();
+    void download();
+    void attemptCancel(boolean userRequested);
 
-        public void run() {
-            try {
-                downloader.download();
-                sendMessage(MSG_DOWNLOAD_COMPLETE);
-            } catch (InterruptedException e) {
-                sendMessage(MSG_DOWNLOAD_CANCELLED);
-            } catch (IOException e) {
-                Log.e(TAG, "I/O exception in download thread", e);
-                Bundle data = new Bundle(1);
-                data.putString(MSG_DATA, e.getLocalizedMessage());
-                Message message = new Message();
-                message.arg1 = MSG_ERROR;
-                message.setData(data);
-                AsyncDownloader.this.sendMessage(message);
-            }
-        }
-
-        private void sendMessage(int messageType) {
-            Message message = new Message();
-            message.arg1 = messageType;
-            AsyncDownloader.this.sendMessage(message);
-        }
-    }
 }

F-Droid/src/org/fdroid/fdroid/net/AsyncDownloaderFromAndroid.java

@@ -23,7 +23,7 @@ import java.io.OutputStream;
  * A downloader that uses Android's DownloadManager to perform a download.
  */
 @TargetApi(Build.VERSION_CODES.GINGERBREAD)
-public class AsyncDownloaderFromAndroid extends AsyncDownloader {
+public class AsyncDownloaderFromAndroid implements AsyncDownloader {
     private final Context context;
     private final DownloadManager dm;
     private File localFile;
@@ -42,7 +42,6 @@ public class AsyncDownloaderFromAndroid extends AsyncDownloader {
      * parameter to the constructor.
      */
     public AsyncDownloaderFromAndroid(Context context, Listener listener, String appName, String appId, String remoteAddress, File localFile) {
-        super(null, listener);
         this.context = context;
         this.appName = appName;
         this.appId = appId;

F-Droid/src/org/fdroid/fdroid/net/DownloaderFactory.java

@@ -5,7 +5,6 @@ import android.os.Build;
 
 import java.io.File;
 import java.io.IOException;
-import java.net.MalformedURLException;
 import java.net.URL;
 
 public class DownloaderFactory {
@@ -62,7 +61,7 @@ public class DownloaderFactory {
         if (canUseDownloadManager(url)) {
             return new AsyncDownloaderFromAndroid(context, listener, title, id, url.toString(), destFile);
         } else {
-            return new AsyncDownloader(create(context, url, destFile), listener);
+            return new AsyncDownloadWrapper(create(context, url, destFile), listener);
         }
     }