Merge lp:~ubuntuone-client-engineering/ubuntuone-music-java-library/playlist-args-and-request-refactor into lp:ubuntuone-music-java-library

[Michał Karnicki]

Refactor RequestListener, so that ResultRequestListener is a parametrized class, while ResultListener has a no-arg onSuccess callback method.

When PUTing playlist to music API v2, name and song_id_list in request JSON body should be optional (at least one of them should be provided), so that it is easy to rename the playlist and update song list without touching its name. Updated JSON generating method, with tests.

Refactored RequestListener class to ResultRequestListener, which has parametrized type argument of onSuccess(.) callback, and introduced RequestListener, which has no argument in onSuccess() callback, for better code readability.

To test, branch and run:
$ ant test

[Brian Curtin (brian.curtin)]

Without being able to run it, the code reads fine given what I've been told about it.

review: Approve

=== modified file 'src/main/com/ubuntuone/api/music/U1MusicAPI.java'
--- src/main/com/ubuntuone/api/music/U1MusicAPI.java	2012-11-08 16:22:16 +0000
+++ src/main/com/ubuntuone/api/music/U1MusicAPI.java	2012-11-08 22:55:22 +0000
@@ -57,17 +57,17 @@
 import com.ubuntuone.api.music.util.CancelTrigger;
 import com.ubuntuone.api.music.util.CancelTrigger.RequestCanceledException;
 import com.ubuntuone.api.music.util.EntityUtils;
+import com.ubuntuone.api.music.util.FailureListener;
 import com.ubuntuone.api.music.util.OnProgressListener;
 import com.ubuntuone.api.music.util.OnProgressListener.ProgressInputStream;
-import com.ubuntuone.api.music.util.RequestListener;
-import com.ubuntuone.api.music.util.RequestListener.U1AlbumRequestListener;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtRequestListener;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtistRequestListener;
-import com.ubuntuone.api.music.util.RequestListener.U1PlaylistRequestListener;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
-import com.ubuntuone.api.music.util.RequestListener.U1StreamRequestListener;
-import com.ubuntuone.api.music.util.RequestListener.U1VoidRequestListener;
+import com.ubuntuone.api.music.util.RequestListener.U1RequestListener;
 import com.ubuntuone.api.music.util.ResponseHeader;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1AlbumRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1PlaylistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1StreamRequestListener;
 import com.ubuntuone.api.music.util.StreamUtils;
 import com.ubuntuone.api.sso.authorizer.Authorizer;
 import com.ubuntuone.api.sso.authorizer.AuthorizerException;
@@ -402,7 +402,7 @@
 		}
 		HttpResponse response = null;
 		try {
-			String data = U1CustomJson.toSongIdListJson(name, songIds);
+			String data = U1CustomJson.toPlaylistJson(name, songIds);
 			response = resourceClient.request(HttpPost.METHOD_NAME, path, null, data);
 			final int statusCode = getStatusCode(response);
 			if (statusCode == HttpStatus.SC_OK) {
@@ -436,7 +436,7 @@
 		}
 	}
 	
-	public void deletePlaylist(String playlistId, U1VoidRequestListener callback) {
+	public void deletePlaylist(String playlistId, U1RequestListener callback) {
 		callback.onStart();
 		String path = resourceClient.getPath(PLAYLISTS, playlistId);
 		HttpResponse response = null;
@@ -444,7 +444,7 @@
 			response = resourceClient.request(HttpDelete.METHOD_NAME, path);
 			final int statusCode = getStatusCode(response);
 			if (statusCode == HttpStatus.SC_OK) {
-				callback.onSuccess(null);
+				callback.onSuccess();
 			} else {
 				handleHttpResponse(response, "Could not delete playlist.", callback);
 			}
@@ -608,7 +608,7 @@
 	}
 	
 	private void handleHttpResponse(HttpResponse response,
-			String message, RequestListener<?> callback) {
+			String message, FailureListener callback) {
 		final int statusCode = getStatusCode(response);
 		
 		switch (statusCode) {
 
=== modified file 'src/main/com/ubuntuone/api/music/json/U1AlbumJson.java'
--- src/main/com/ubuntuone/api/music/json/U1AlbumJson.java	2012-09-04 21:42:33 +0000
+++ src/main/com/ubuntuone/api/music/json/U1AlbumJson.java	2012-11-08 22:55:22 +0000
@@ -34,7 +34,7 @@
 
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Album;
-import com.ubuntuone.api.music.util.RequestListener.U1AlbumRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1AlbumRequestListener;
 
 public class U1AlbumJson
 {
 
=== modified file 'src/main/com/ubuntuone/api/music/json/U1ArtistJson.java'
--- src/main/com/ubuntuone/api/music/json/U1ArtistJson.java	2012-09-04 21:42:33 +0000
+++ src/main/com/ubuntuone/api/music/json/U1ArtistJson.java	2012-11-08 22:55:22 +0000
@@ -35,7 +35,7 @@
 
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Artist;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtistRequestListener;
 
 public class U1ArtistJson
 {
 
=== modified file 'src/main/com/ubuntuone/api/music/json/U1CustomJson.java'
--- src/main/com/ubuntuone/api/music/json/U1CustomJson.java	2012-09-19 19:17:30 +0000
+++ src/main/com/ubuntuone/api/music/json/U1CustomJson.java	2012-11-08 22:55:22 +0000
@@ -30,22 +30,36 @@
 
 public class U1CustomJson
 {
-	public static String toSongIdListJson(String name, ArrayList<String> songIds)
-			throws IOException {
+	/**
+	 * Either name or songIds has to be provided. Otherwise, request with such
+	 * body will fail.
+	 * 
+	 * @param name
+	 *            The name of the playlist.
+	 * @param songIdList
+	 *            The song id list of the playlist.
+	 * @return Request JSON body.
+	 * @throws IOException
+	 *             If JSON generation fails with IOException.
+	 */
+	public static String toPlaylistJson(String name,
+			ArrayList<String> songIdList) throws IOException {
 		final JsonFactory factory = new JsonFactory();
 		final StringWriter writer = new StringWriter(128);
 		final JsonGenerator g = factory.createJsonGenerator(writer);
 		
 		g.writeStartObject();
-		g.writeStringField("name", name);
-		
-		g.writeArrayFieldStart("song_id_list"); {
-			for (String songId: songIds) {
-				g.writeString(songId);
+		if (name != null) {
+			g.writeStringField("name", name);
+		}
+		if (songIdList != null) {
+			g.writeArrayFieldStart("song_id_list"); {
+				for (String songId: songIdList) {
+					g.writeString(songId);
+				}
 			}
+			g.writeEndArray();
 		}
-		g.writeEndArray();
-		
 		g.writeEndObject();
 		g.close();
 		
 
=== modified file 'src/main/com/ubuntuone/api/music/json/U1PlaylistJson.java'
--- src/main/com/ubuntuone/api/music/json/U1PlaylistJson.java	2012-09-04 21:42:33 +0000
+++ src/main/com/ubuntuone/api/music/json/U1PlaylistJson.java	2012-11-08 22:55:22 +0000
@@ -35,7 +35,7 @@
 
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Playlist;
-import com.ubuntuone.api.music.util.RequestListener.U1PlaylistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1PlaylistRequestListener;
 
 public class U1PlaylistJson
 {
 
=== modified file 'src/main/com/ubuntuone/api/music/json/U1SongJson.java'
--- src/main/com/ubuntuone/api/music/json/U1SongJson.java	2012-09-04 21:42:33 +0000
+++ src/main/com/ubuntuone/api/music/json/U1SongJson.java	2012-11-08 22:55:22 +0000
@@ -34,7 +34,7 @@
 
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
 
 public class U1SongJson
 {
 
=== modified file 'src/main/com/ubuntuone/api/music/request/U1AlbumListener.java'
--- src/main/com/ubuntuone/api/music/request/U1AlbumListener.java	2012-06-07 01:31:25 +0000
+++ src/main/com/ubuntuone/api/music/request/U1AlbumListener.java	2012-11-08 22:55:22 +0000
@@ -23,7 +23,7 @@
 
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Album;
-import com.ubuntuone.api.music.util.RequestListener.U1AlbumRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1AlbumRequestListener;
 
 public abstract class U1AlbumListener implements U1AlbumRequestListener
 {
 
=== modified file 'src/main/com/ubuntuone/api/music/request/U1ArtListener.java'
--- src/main/com/ubuntuone/api/music/request/U1ArtListener.java	2012-06-18 04:19:36 +0000
+++ src/main/com/ubuntuone/api/music/request/U1ArtListener.java	2012-11-08 22:55:22 +0000
@@ -24,7 +24,7 @@
 import java.io.File;
 
 import com.ubuntuone.api.music.client.Failure;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtRequestListener;
 
 public abstract class U1ArtListener implements U1ArtRequestListener
 {
 
=== modified file 'src/main/com/ubuntuone/api/music/request/U1ArtistListener.java'
--- src/main/com/ubuntuone/api/music/request/U1ArtistListener.java	2012-06-07 01:31:25 +0000
+++ src/main/com/ubuntuone/api/music/request/U1ArtistListener.java	2012-11-08 22:55:22 +0000
@@ -23,7 +23,7 @@
 
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Artist;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtistRequestListener;
 
 public abstract class U1ArtistListener implements U1ArtistRequestListener
 {
 
=== added file 'src/main/com/ubuntuone/api/music/request/U1CallbackListener.java'
--- src/main/com/ubuntuone/api/music/request/U1CallbackListener.java	1970-01-01 00:00:00 +0000
+++ src/main/com/ubuntuone/api/music/request/U1CallbackListener.java	2012-11-08 22:55:22 +0000
@@ -0,0 +1,47 @@
+/*
+ * Ubuntu One Music Java library - communicate with Ubuntu One music API
+ * 
+ * Copyright 2012 Canonical Ltd.
+ *   
+ * This file is part of Ubuntu One Files Java library.
+ *  
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *  
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *  
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses 
+ */
+
+package com.ubuntuone.api.music.request;
+
+import com.ubuntuone.api.music.client.Failure;
+import com.ubuntuone.api.music.util.RequestListener.U1RequestListener;
+
+/**
+ * Class used for callbacks from methods, that do not return result
+ * in onSuccess(), but simply call it to indicate success.
+ */
+public abstract class U1CallbackListener implements U1RequestListener
+{
+	@Override
+	public void onStart() {
+	}
+
+	@Override
+	public abstract void onSuccess();
+
+	@Override
+	public void onFailure(Failure failure) {
+	}
+
+	@Override
+	public void onFinish() {
+	}
+}
 
=== modified file 'src/main/com/ubuntuone/api/music/request/U1DownloadListener.java'
--- src/main/com/ubuntuone/api/music/request/U1DownloadListener.java	2012-06-19 01:05:51 +0000
+++ src/main/com/ubuntuone/api/music/request/U1DownloadListener.java	2012-11-08 22:55:22 +0000
@@ -24,9 +24,9 @@
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.util.OnCancelListener;
 import com.ubuntuone.api.music.util.OnProgressListener;
-import com.ubuntuone.api.music.util.RequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener;
 
-public abstract class U1DownloadListener implements RequestListener<Boolean>,
+public abstract class U1DownloadListener implements ResultRequestListener<Boolean>,
 		OnProgressListener, OnCancelListener
 {
 	@Override
 
=== modified file 'src/main/com/ubuntuone/api/music/request/U1PlaylistListener.java'
--- src/main/com/ubuntuone/api/music/request/U1PlaylistListener.java	2012-06-07 01:31:25 +0000
+++ src/main/com/ubuntuone/api/music/request/U1PlaylistListener.java	2012-11-08 22:55:22 +0000
@@ -23,7 +23,7 @@
 
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Playlist;
-import com.ubuntuone.api.music.util.RequestListener.U1PlaylistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1PlaylistRequestListener;
 
 public abstract class U1PlaylistListener implements U1PlaylistRequestListener
 {
 
=== removed file 'src/main/com/ubuntuone/api/music/request/U1RequestListener.java'
--- src/main/com/ubuntuone/api/music/request/U1RequestListener.java	2012-06-18 03:10:10 +0000
+++ src/main/com/ubuntuone/api/music/request/U1RequestListener.java	1970-01-01 00:00:00 +0000
@@ -1,47 +0,0 @@
-/*
- * Ubuntu One Music Java library - communicate with Ubuntu One music API
- * 
- * Copyright 2012 Canonical Ltd.
- *   
- * This file is part of Ubuntu One Files Java library.
- *  
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as
- * published by the Free Software Foundation, either version 3 of the
- * License, or (at your option) any later version.
- *  
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *  
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see http://www.gnu.org/licenses 
- */
-
-package com.ubuntuone.api.music.request;
-
-import com.ubuntuone.api.music.client.Failure;
-import com.ubuntuone.api.music.util.RequestListener.U1VoidRequestListener;
-
-/**
- * Class used for callbacks from methods, that do not return result
- * in onSuccess(), but simply call it to indicate success.
- */
-public abstract class U1RequestListener implements U1VoidRequestListener
-{
-	@Override
-	public void onStart() {
-	}
-
-	@Override
-	public abstract void onSuccess(Void v);
-
-	@Override
-	public void onFailure(Failure failure) {
-	}
-
-	@Override
-	public void onFinish() {
-	}
-}
 
=== modified file 'src/main/com/ubuntuone/api/music/request/U1SongListener.java'
--- src/main/com/ubuntuone/api/music/request/U1SongListener.java	2012-06-07 01:31:25 +0000
+++ src/main/com/ubuntuone/api/music/request/U1SongListener.java	2012-11-08 22:55:22 +0000
@@ -23,7 +23,7 @@
 
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
 
 public abstract class U1SongListener implements U1SongRequestListener
 {
 
=== added file 'src/main/com/ubuntuone/api/music/util/FailureListener.java'
--- src/main/com/ubuntuone/api/music/util/FailureListener.java	1970-01-01 00:00:00 +0000
+++ src/main/com/ubuntuone/api/music/util/FailureListener.java	2012-11-08 22:55:22 +0000
@@ -0,0 +1,18 @@
+package com.ubuntuone.api.music.util;
+
+import org.apache.http.HttpStatus;
+
+import com.ubuntuone.api.music.client.Failure;
+
+public abstract interface FailureListener {
+	/**
+	 * Called when the request has failed. The message should be descriptive
+	 * in most cases and suitable to display to the user.
+	 * {@link Failure#getStatusCode} field can be compared with
+	 * {@link HttpStatus} constants for further details.
+	 * 
+	 * @param failure
+	 *            The {@link Failure} returned.
+	 */
+	public void onFailure(Failure failure);
+}
 
=== modified file 'src/main/com/ubuntuone/api/music/util/RequestListener.java'
--- src/main/com/ubuntuone/api/music/util/RequestListener.java	2012-08-27 17:20:36 +0000
+++ src/main/com/ubuntuone/api/music/util/RequestListener.java	2012-11-08 22:55:22 +0000
@@ -21,24 +21,11 @@
 
 package com.ubuntuone.api.music.util;
 
-import java.io.File;
-import java.io.InputStream;
-
-import org.apache.http.HttpStatus;
-
-import com.ubuntuone.api.music.client.Failure;
-import com.ubuntuone.api.music.model.U1Album;
-import com.ubuntuone.api.music.model.U1Artist;
-import com.ubuntuone.api.music.model.U1Playlist;
-import com.ubuntuone.api.music.model.U1Song;
 
 /**
  * Request listener used to track U1 API method execution.
- * 
- * @param <T>
- *            The type of result returned in {@link RequestListener#onSuccess(T)}.
  */
-public interface RequestListener<T>
+public interface RequestListener extends FailureListener
 {
 	/**
 	 * Called when the request processing has started.
@@ -47,34 +34,14 @@
 	
 	/**
 	 * Called when the request has successfully completed.
-	 * 
-	 * @param result
-	 *            The request result of type T.
-	 */
-	public void onSuccess(T result);
-	
-	/**
-	 * Called when the request has failed. The message should be descriptive
-	 * in most cases and suitable to display to the user.
-	 * {@link Failure#getStatusCode} field can be compared with
-	 * {@link HttpStatus} constants for further details.
-	 * 
-	 * @param failure
-	 *            The {@link Failure} returned.
-	 */
-	public void onFailure(Failure failure);
+	 */
+	public void onSuccess();
 	
 	/**
 	 * Called when the request processing has finished.
 	 */
 	public void onFinish();
 	
-	public interface U1ArtistRequestListener extends RequestListener<U1Artist> {};
-	public interface U1AlbumRequestListener extends RequestListener<U1Album> {};
-	public interface U1SongRequestListener extends RequestListener<U1Song> {};
-	public interface U1PlaylistRequestListener extends RequestListener<U1Playlist> {};
-	public interface U1PlaylistSongRequestListener extends RequestListener<U1Song> {};
-	public interface U1ArtRequestListener extends RequestListener<File> {};
-	public interface U1VoidRequestListener extends RequestListener<Void> {};
-	public interface U1StreamRequestListener extends RequestListener<InputStream> {};
-}
 \ No newline at end of file
+	
+	public interface U1RequestListener extends RequestListener {};
+}
 
=== added file 'src/main/com/ubuntuone/api/music/util/ResultRequestListener.java'
--- src/main/com/ubuntuone/api/music/util/ResultRequestListener.java	1970-01-01 00:00:00 +0000
+++ src/main/com/ubuntuone/api/music/util/ResultRequestListener.java	2012-11-08 22:55:22 +0000
@@ -0,0 +1,67 @@
+/*
+ * Ubuntu One Music Java library - communicate with Ubuntu One music API
+ * 
+ * Copyright 2012 Canonical Ltd.
+ *   
+ * This file is part of Ubuntu One Files Java library.
+ *  
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *  
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *  
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses 
+ */
+
+package com.ubuntuone.api.music.util;
+
+import java.io.File;
+import java.io.InputStream;
+
+import com.ubuntuone.api.music.model.U1Album;
+import com.ubuntuone.api.music.model.U1Artist;
+import com.ubuntuone.api.music.model.U1Playlist;
+import com.ubuntuone.api.music.model.U1Song;
+
+/**
+ * Request listener used to track U1 API method execution.
+ * 
+ * @param <T>
+ *            The type of result returned in {@link ResultRequestListener#onSuccess(T)}.
+ */
+public interface ResultRequestListener<T> extends FailureListener
+{
+	/**
+	 * Called when the request processing has started.
+	 */
+	public void onStart();
+	
+	/**
+	 * Called when the request has successfully completed.
+	 * 
+	 * @param result
+	 *            The request result of type T.
+	 */
+	public void onSuccess(T result);
+	
+	/**
+	 * Called when the request processing has finished.
+	 */
+	public void onFinish();
+	
+	public interface U1ArtistRequestListener extends ResultRequestListener<U1Artist> {};
+	public interface U1AlbumRequestListener extends ResultRequestListener<U1Album> {};
+	public interface U1SongRequestListener extends ResultRequestListener<U1Song> {};
+	
+	public interface U1PlaylistRequestListener extends ResultRequestListener<U1Playlist> {};
+	public interface U1PlaylistSongRequestListener extends ResultRequestListener<U1Song> {};
+	
+	public interface U1ArtRequestListener extends ResultRequestListener<File> {};
+	public interface U1StreamRequestListener extends ResultRequestListener<InputStream> {};
+}
 
=== modified file 'src/test/com/ubuntuone/api/music/CreatePlaylistTest.java'
--- src/test/com/ubuntuone/api/music/CreatePlaylistTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/CreatePlaylistTest.java	2012-11-08 22:55:22 +0000
@@ -48,7 +48,7 @@
 import com.ubuntuone.api.music.json.U1CustomJson;
 import com.ubuntuone.api.music.model.U1Meta;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.U1SongBuilder;
 import com.ubuntuone.music.util.Util;
@@ -125,7 +125,7 @@
 				"/api/music/v2/playlists/");
 		
 		httpRequest.setEntity(new StringEntity(U1CustomJson
-				.toSongIdListJson(name, songIdList)));
+				.toPlaylistJson(name, songIdList)));
 		
 		String responseJson = U1ResponseBuilder.toJson(
 				meta, U1MusicAPI.SONGS, id, name, song1, song2, song3);
@@ -178,7 +178,7 @@
 				"/api/music/v2/playlists/");
 		
 		httpRequest.setEntity(new StringEntity(U1CustomJson
-				.toSongIdListJson(name, songIdList)));
+				.toPlaylistJson(name, songIdList)));
 		
 		String responseJson = U1ResponseBuilder.toJson(
 				meta, U1MusicAPI.SONGS, id, name, song1, song2, song3);
 
=== modified file 'src/test/com/ubuntuone/api/music/DeletePlaylistTest.java'
--- src/test/com/ubuntuone/api/music/DeletePlaylistTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/DeletePlaylistTest.java	2012-11-08 22:55:22 +0000
@@ -45,7 +45,7 @@
 import com.ubuntuone.api.music.client.BaseClient;
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Meta;
-import com.ubuntuone.api.music.util.RequestListener.U1VoidRequestListener;
+import com.ubuntuone.api.music.util.RequestListener.U1RequestListener;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.Util;
 import com.ubuntuone.test.util.DummyAuthorizer;
@@ -64,7 +64,7 @@
 	private U1MusicAPI musicApi;
 
 	String playlistId = "playlistId";
-	private U1VoidRequestListener requestCallback;
+	private U1RequestListener requestCallback;
 	
 	@Before
 	public void setUp() throws IOException {
@@ -75,7 +75,7 @@
 		httpClient = context.mock(HttpClient.class);
 		musicApi = new U1MusicAPI("ua/1.0", httpClient, new DummyAuthorizer());
 		
-		requestCallback = context.mock(U1VoidRequestListener.class);
+		requestCallback = context.mock(U1RequestListener.class);
 	}
 	
 	@Test
@@ -86,7 +86,7 @@
 					inSequence(requestSequence);
 			
 			ignoring(httpClient);
-			allowing(requestCallback).onSuccess(with(any(Void.class)));
+			allowing(requestCallback).onSuccess();
 			allowing(requestCallback).onFailure(with(any(Failure.class)));
 			
 			oneOf(requestCallback).onFinish();
@@ -118,7 +118,7 @@
 					inSequence(requestSequence);
 							will(returnValue(httpResponse));
 			
-			oneOf(requestCallback).onSuccess(null);
+			oneOf(requestCallback).onSuccess();
 					inSequence(requestSequence);
 			
 			oneOf(requestCallback).onFinish();
 
=== modified file 'src/test/com/ubuntuone/api/music/GetAlbumsTest.java'
--- src/test/com/ubuntuone/api/music/GetAlbumsTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/GetAlbumsTest.java	2012-11-08 22:55:22 +0000
@@ -47,7 +47,7 @@
 import com.ubuntuone.api.music.model.U1Album;
 import com.ubuntuone.api.music.model.U1Artist;
 import com.ubuntuone.api.music.model.U1Meta;
-import com.ubuntuone.api.music.util.RequestListener.U1AlbumRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1AlbumRequestListener;
 import com.ubuntuone.music.util.U1AlbumBuilder;
 import com.ubuntuone.music.util.U1ArtistBuilder;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 
=== modified file 'src/test/com/ubuntuone/api/music/GetArtTest.java'
--- src/test/com/ubuntuone/api/music/GetArtTest.java	2012-09-19 19:17:30 +0000
+++ src/test/com/ubuntuone/api/music/GetArtTest.java	2012-11-08 22:55:22 +0000
@@ -51,7 +51,7 @@
 import com.ubuntuone.api.music.model.U1Artist;
 import com.ubuntuone.api.music.model.U1Song;
 import com.ubuntuone.api.music.util.HashUtils;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtRequestListener;
 import com.ubuntuone.music.util.U1AlbumBuilder;
 import com.ubuntuone.music.util.U1ArtistBuilder;
 import com.ubuntuone.music.util.U1SongBuilder;
 
=== modified file 'src/test/com/ubuntuone/api/music/GetArtistsTest.java'
--- src/test/com/ubuntuone/api/music/GetArtistsTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/GetArtistsTest.java	2012-11-08 22:55:22 +0000
@@ -46,7 +46,7 @@
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Artist;
 import com.ubuntuone.api.music.model.U1Meta;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtistRequestListener;
 import com.ubuntuone.music.util.U1ArtistBuilder;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.Util;
 
=== modified file 'src/test/com/ubuntuone/api/music/GetPlaylistTest.java'
--- src/test/com/ubuntuone/api/music/GetPlaylistTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/GetPlaylistTest.java	2012-11-08 22:55:22 +0000
@@ -46,7 +46,7 @@
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Meta;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.U1SongBuilder;
 import com.ubuntuone.music.util.Util;
 
=== modified file 'src/test/com/ubuntuone/api/music/GetPlaylistsTest.java'
--- src/test/com/ubuntuone/api/music/GetPlaylistsTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/GetPlaylistsTest.java	2012-11-08 22:55:22 +0000
@@ -46,7 +46,7 @@
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Meta;
 import com.ubuntuone.api.music.model.U1Playlist;
-import com.ubuntuone.api.music.util.RequestListener.U1PlaylistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1PlaylistRequestListener;
 import com.ubuntuone.music.util.U1PlaylistBuilder;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.Util;
 
=== modified file 'src/test/com/ubuntuone/api/music/GetSongStreamTest.java'
--- src/test/com/ubuntuone/api/music/GetSongStreamTest.java	2012-11-08 16:22:16 +0000
+++ src/test/com/ubuntuone/api/music/GetSongStreamTest.java	2012-11-08 22:55:22 +0000
@@ -47,7 +47,7 @@
 import com.ubuntuone.api.music.client.BaseClient;
 import com.ubuntuone.api.music.client.Failure;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1StreamRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1StreamRequestListener;
 import com.ubuntuone.music.util.U1SongBuilder;
 import com.ubuntuone.music.util.Util;
 import com.ubuntuone.test.util.DummyAuthorizer;
 
=== modified file 'src/test/com/ubuntuone/api/music/GetSongsTest.java'
--- src/test/com/ubuntuone/api/music/GetSongsTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/GetSongsTest.java	2012-11-08 22:55:22 +0000
@@ -47,7 +47,7 @@
 import com.ubuntuone.api.music.model.U1Album;
 import com.ubuntuone.api.music.model.U1Meta;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
 import com.ubuntuone.music.util.U1AlbumBuilder;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.U1SongBuilder;
 
=== modified file 'src/test/com/ubuntuone/api/music/UpdatePlaylistTest.java'
--- src/test/com/ubuntuone/api/music/UpdatePlaylistTest.java	2012-09-28 01:45:13 +0000
+++ src/test/com/ubuntuone/api/music/UpdatePlaylistTest.java	2012-11-08 22:55:22 +0000
@@ -48,7 +48,7 @@
 import com.ubuntuone.api.music.json.U1CustomJson;
 import com.ubuntuone.api.music.model.U1Meta;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.U1SongBuilder;
 import com.ubuntuone.music.util.Util;
@@ -125,7 +125,7 @@
 				"/api/music/v2/playlists/");
 		
 		httpRequest.setEntity(new StringEntity(U1CustomJson
-				.toSongIdListJson(name, songList)));
+				.toPlaylistJson(name, songList)));
 		
 		String responseJson = U1ResponseBuilder.toJson(
 				meta, U1MusicAPI.SONGS, id, name, song1, song2, song3);
 
=== modified file 'src/test/com/ubuntuone/api/music/json/U1AlbumJsonTest.java'
--- src/test/com/ubuntuone/api/music/json/U1AlbumJsonTest.java	2012-06-12 02:39:48 +0000
+++ src/test/com/ubuntuone/api/music/json/U1AlbumJsonTest.java	2012-11-08 22:55:22 +0000
@@ -35,7 +35,7 @@
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Album;
 import com.ubuntuone.api.music.model.U1Meta;
-import com.ubuntuone.api.music.util.RequestListener.U1AlbumRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1AlbumRequestListener;
 import com.ubuntuone.music.util.U1AlbumBuilder;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 
 
=== modified file 'src/test/com/ubuntuone/api/music/json/U1ArtistJsonTest.java'
--- src/test/com/ubuntuone/api/music/json/U1ArtistJsonTest.java	2012-09-04 19:28:22 +0000
+++ src/test/com/ubuntuone/api/music/json/U1ArtistJsonTest.java	2012-11-08 22:55:22 +0000
@@ -35,7 +35,7 @@
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Artist;
 import com.ubuntuone.api.music.model.U1Meta;
-import com.ubuntuone.api.music.util.RequestListener.U1ArtistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1ArtistRequestListener;
 import com.ubuntuone.music.util.U1ArtistBuilder;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 
 
=== modified file 'src/test/com/ubuntuone/api/music/json/U1CustomJsonTest.java'
--- src/test/com/ubuntuone/api/music/json/U1CustomJsonTest.java	2012-09-19 19:17:30 +0000
+++ src/test/com/ubuntuone/api/music/json/U1CustomJsonTest.java	2012-11-08 22:55:22 +0000
@@ -31,7 +31,7 @@
 public class U1CustomJsonTest
 {
 	@Test
-	public void testEncodeU1SongIdListPlaylist() throws IOException {
+	public void testToPlaylistJson() throws IOException {
 		final ArrayList<String> songIdList = new ArrayList<String>();
 		
 		songIdList.add("id1");
@@ -39,7 +39,7 @@
 		
 		String name = "the playlist name";
 		
-		String json = U1CustomJson.toSongIdListJson(name, songIdList);
+		String json = U1CustomJson.toPlaylistJson(name, songIdList);
 		
 		String expectedJson = "{\"name\":\"" + name + "\"," +
 				"\"song_id_list\":[" +
@@ -48,4 +48,28 @@
 		
 		assertEquals(expectedJson, json);
 	}
+	
+	@Test
+	public void testToPlaylistJsonNameOnly() throws IOException {
+		String name = "the playlist name";
+		
+		String json = U1CustomJson.toPlaylistJson(name, null);
+		
+		String expectedJson = "{\"name\":\"" + name + "\"}";
+		
+		assertEquals(expectedJson, json);
+	}
+	
+	@Test
+	public void testToPlaylistJsonSongIdListOnly() throws IOException {
+		final ArrayList<String> songIdList = new ArrayList<String>();
+		songIdList.add("id1");
+		songIdList.add("id2");
+		
+		String json = U1CustomJson.toPlaylistJson(null, songIdList);
+		
+		String expectedJson = "{\"song_id_list\":[\"id1\",\"id2\"]}";
+		
+		assertEquals(expectedJson, json);
+	}
 }
 
=== modified file 'src/test/com/ubuntuone/api/music/json/U1PlaylistJsonTest.java'
--- src/test/com/ubuntuone/api/music/json/U1PlaylistJsonTest.java	2012-06-12 14:44:04 +0000
+++ src/test/com/ubuntuone/api/music/json/U1PlaylistJsonTest.java	2012-11-08 22:55:22 +0000
@@ -35,7 +35,7 @@
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Meta;
 import com.ubuntuone.api.music.model.U1Playlist;
-import com.ubuntuone.api.music.util.RequestListener.U1PlaylistRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1PlaylistRequestListener;
 import com.ubuntuone.music.util.U1PlaylistBuilder;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 
 
=== modified file 'src/test/com/ubuntuone/api/music/json/U1SongJsonTest.java'
--- src/test/com/ubuntuone/api/music/json/U1SongJsonTest.java	2012-06-12 02:39:48 +0000
+++ src/test/com/ubuntuone/api/music/json/U1SongJsonTest.java	2012-11-08 22:55:22 +0000
@@ -35,7 +35,7 @@
 import com.ubuntuone.api.music.U1MusicAPI;
 import com.ubuntuone.api.music.model.U1Meta;
 import com.ubuntuone.api.music.model.U1Song;
-import com.ubuntuone.api.music.util.RequestListener.U1SongRequestListener;
+import com.ubuntuone.api.music.util.ResultRequestListener.U1SongRequestListener;
 import com.ubuntuone.music.util.U1ResponseBuilder;
 import com.ubuntuone.music.util.U1SongBuilder;
 
 
=== modified file 'src/test/com/ubuntuone/music/util/U1ResponseBuilder.java'
--- src/test/com/ubuntuone/music/util/U1ResponseBuilder.java	2012-08-27 17:20:36 +0000
+++ src/test/com/ubuntuone/music/util/U1ResponseBuilder.java	2012-11-08 22:55:22 +0000
@@ -33,6 +33,9 @@
 
 public class U1ResponseBuilder
 {
+	private static final String META = "meta";
+	private static final String STATUS = "status";
+	private static final String MSG = "msg";
 	private static final String RESPONSE = "response";
 	
 	public static String toJson(U1Meta meta, String title, JSONString... items)
@@ -48,24 +51,23 @@
 		final JsonGenerator g = factory.createJsonGenerator(writer);
 		
 		g.writeStartObject(); {
-			// meta
-			g.writeObjectFieldStart("meta"); {
-				g.writeNumberField("status", meta.getStatus());
-				g.writeStringField("msg", meta.getMessage());
+			g.writeObjectFieldStart(META); {
+				g.writeNumberField(STATUS, meta.getStatus());
+				g.writeStringField(MSG, meta.getMessage());
 			}
 			g.writeEndObject();
-			// response
+			
 			g.writeObjectFieldStart(RESPONSE); {
-				// item array
 				g.writeArrayFieldStart(title);
 				if (items != null) {
 					for (JSONString item : items) {
 						g.writeRawValue(item.toJSONString());
 					}
 				}
-				g.writeEndArray(); // title
+				g.writeEndArray();
 			}
-			g.writeEndObject(); // response
+			g.writeEndObject();
+			
 		}
 		g.writeEndObject();
 		g.close();