Merge "Add Session2Command and Session2CommandGroup"

2 files changed, 917 insertions, 0 deletions

diff --git a/media/java/android/media/Session2Command.java b/media/java/android/media/Session2Command.java
new file mode 100644
index 000000000000..a5e2ae4488a9
--- /dev/null
+++ b/media/java/android/media/Session2Command.java
@@ -0,0 +1,596 @@
+/*
+ * Copyright 2018 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 android.media;
+
+import android.annotation.IntDef;
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.os.Bundle;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.text.TextUtils;
+import android.util.ArrayMap;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Define a command that a {@link MediaController2} can send to a {@link MediaSession2}.
+ * <p>
+ * If {@link #getCommandCode()} isn't {@link #COMMAND_CODE_CUSTOM}), it's predefined command.
+ * If {@link #getCommandCode()} is {@link #COMMAND_CODE_CUSTOM}), it's custom command and
+ * {@link #getCustomCommand()} shouldn't be {@code null}.
+ * <p>
+ * This API is not generally intended for third party application developers.
+ * Use the <a href="{@docRoot}jetpack/androidx.html">AndroidX</a>
+ * <a href="{@docRoot}reference/androidx/media2/package-summary.html">Media2 Library</a>
+ * for consistent behavior across all devices.
+ * </p>
+ * @hide
+ */
+public final class Session2Command implements Parcelable {
+    /**
+     * The first version of session commands. This version is for commands introduced in API 29.
+     * <p>
+     * This would be used to specify which commands should be added by
+     * {@link Session2CommandGroup.Builder#addAllPredefinedCommands(int)}
+     *
+     * @see Session2CommandGroup.Builder#addAllPredefinedCommands(int)
+     */
+    public static final int COMMAND_VERSION_1 = 1;
+
+    /**
+     * @hide
+     */
+    public static final int COMMAND_VERSION_CURRENT = COMMAND_VERSION_1;
+
+    /**
+     * @hide
+     */
+    @IntDef({COMMAND_VERSION_1})
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface CommandVersion {}
+
+    /**
+     * @hide
+     */
+    @IntDef({COMMAND_CODE_CUSTOM,
+            COMMAND_CODE_PLAYER_PLAY,
+            COMMAND_CODE_PLAYER_PAUSE,
+            COMMAND_CODE_PLAYER_PREPARE,
+            COMMAND_CODE_PLAYER_SEEK_TO,
+            COMMAND_CODE_PLAYER_SET_SPEED,
+            COMMAND_CODE_PLAYER_GET_PLAYLIST,
+            COMMAND_CODE_PLAYER_SET_PLAYLIST,
+            COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM,
+            COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM,
+            COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM,
+            COMMAND_CODE_PLAYER_SET_SHUFFLE_MODE,
+            COMMAND_CODE_PLAYER_SET_REPEAT_MODE,
+            COMMAND_CODE_PLAYER_GET_PLAYLIST_METADATA,
+            COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM,
+            COMMAND_CODE_PLAYER_REMOVE_PLAYLIST_ITEM,
+            COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM,
+            COMMAND_CODE_PLAYER_GET_CURRENT_MEDIA_ITEM,
+            COMMAND_CODE_PLAYER_UPDATE_LIST_METADATA,
+            COMMAND_CODE_PLAYER_SET_MEDIA_ITEM,
+            COMMAND_CODE_VOLUME_SET_VOLUME,
+            COMMAND_CODE_VOLUME_ADJUST_VOLUME,
+            COMMAND_CODE_SESSION_FAST_FORWARD,
+            COMMAND_CODE_SESSION_REWIND,
+            COMMAND_CODE_SESSION_SKIP_FORWARD,
+            COMMAND_CODE_SESSION_SKIP_BACKWARD,
+            COMMAND_CODE_SESSION_SET_RATING,
+            COMMAND_CODE_LIBRARY_GET_LIBRARY_ROOT,
+            COMMAND_CODE_LIBRARY_SUBSCRIBE,
+            COMMAND_CODE_LIBRARY_UNSUBSCRIBE,
+            COMMAND_CODE_LIBRARY_GET_CHILDREN,
+            COMMAND_CODE_LIBRARY_GET_ITEM,
+            COMMAND_CODE_LIBRARY_SEARCH,
+            COMMAND_CODE_LIBRARY_GET_SEARCH_RESULT
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface CommandCode {}
+
+    /**
+     * Command code for the custom command which can be defined by string action in the
+     * {@link Session2Command}.
+     */
+    public static final int COMMAND_CODE_CUSTOM = 0;
+
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    // Player commands (i.e. commands to {@link Session2Player})
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    static final ArrayMap<Integer, Range> VERSION_PLAYER_COMMANDS_MAP = new ArrayMap<>();
+    static final ArrayMap<Integer, Range> VERSION_PLAYER_PLAYLIST_COMMANDS_MAP = new ArrayMap<>();
+
+    // TODO: check the link tag, and reassign int values properly.
+    /**
+     * Command code for {@link MediaController2#play()}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info,
+     * Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_PLAY = 10000;
+
+    /**
+     * Command code for {@link MediaController2#pause()}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info,
+     * Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_PAUSE = 10001;
+
+    /**
+     * Command code for {@link MediaController2#prepare()}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info,
+     * Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_PREPARE = 10002;
+
+    /**
+     * Command code for {@link MediaController2#seekTo(long)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info,
+     * Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SEEK_TO = 10003;
+
+    /**
+     * Command code for {@link MediaController2#setPlaybackSpeed(float)}}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the {@link Session22Callback#onCommandRequest(MediaSession2, Controller2Info,
+     * Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SET_SPEED = 10004;
+
+    /**
+     * Command code for {@link MediaController2#getPlaylist()}. This will expose metadata
+     * information to the controller.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_GET_PLAYLIST = 10005;
+
+    /**
+     * Command code for {@link MediaController2#setPlaylist(List, MediaMetadata)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SET_PLAYLIST = 10006;
+
+    /**
+     * Command code for {@link MediaController2#skipToPlaylistItem(int)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM = 10007;
+
+    /**
+     * Command code for {@link MediaController2#skipToPreviousPlaylistItem()}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the {@link Session2Callback#onCommandRequest(
+     * MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM = 10008;
+
+    /**
+     * Command code for {@link MediaController2#skipToNextPlaylistItem()}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the {@link Session2Callback#onCommandRequest(
+     * MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+
+    public static final int COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM = 10009;
+
+    /**
+     * Command code for {@link MediaController2#setShuffleMode(int)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SET_SHUFFLE_MODE = 10010;
+
+    /**
+     * Command code for {@link MediaController2#setRepeatMode(int)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SET_REPEAT_MODE = 10011;
+
+    /**
+     * Command code for {@link MediaController2#getPlaylistMetadata()}. This will expose metadata
+     * information to the controller.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_GET_PLAYLIST_METADATA = 10012;
+
+    /**
+     * Command code for {@link MediaController2#addPlaylistItem(int, String)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM = 10013;
+
+    /**
+     * Command code for {@link MediaController2#removePlaylistItem(int, String)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_REMOVE_PLAYLIST_ITEM = 10014;
+
+    /**
+     * Command code for {@link MediaController2#replacePlaylistItem(int, String)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM = 10015;
+
+    /**
+     * Command code for {@link MediaController2#getCurrentMediaItem()}. This will expose metadata
+     * information to the controller.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_GET_CURRENT_MEDIA_ITEM = 10016;
+
+    /**
+     * Command code for {@link MediaController2#updatePlaylistMetadata(MediaMetadata)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_UPDATE_LIST_METADATA = 10017;
+
+    /**
+     * Command code for {@link MediaController2#setMediaItem(String)}.
+     * <p>
+     * Command would be sent directly to the player if the session doesn't reject the request
+     * through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_PLAYER_SET_MEDIA_ITEM = 10018;
+
+    static {
+        VERSION_PLAYER_COMMANDS_MAP.put(COMMAND_VERSION_1,
+                new Range(COMMAND_CODE_PLAYER_PLAY, COMMAND_CODE_PLAYER_SET_MEDIA_ITEM));
+    }
+
+    static {
+        VERSION_PLAYER_PLAYLIST_COMMANDS_MAP.put(COMMAND_VERSION_1,
+                new Range(COMMAND_CODE_PLAYER_GET_PLAYLIST,
+                        COMMAND_CODE_PLAYER_SET_MEDIA_ITEM));
+    }
+
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    // Volume commands (i.e. commands to {@link AudioManager} or {@link RouteMediaPlayer})
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    static final ArrayMap<Integer, Range> VERSION_VOLUME_COMMANDS_MAP = new ArrayMap<>();
+
+    /**
+     * Command code for {@link MediaController2#setVolumeTo(int, int)}.
+     * <p>
+     * <p>
+     * If the session doesn't reject the request through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)},
+     * command would adjust the device volume. It would send to the player directly only if it's
+     * remote player. See RouteMediaPlayer for a remote player.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_VOLUME_SET_VOLUME = 30000;
+
+    /**
+     * Command code for {@link MediaController2#adjustVolume(int, int)}.
+     * <p>
+     * If the session doesn't reject the request through the
+     * {@link Session2Callback#onCommandRequest(MediaSession2, Controller2Info, Session2Command)},
+     * command would adjust the device volume. It would send to the player directly only if it's
+     * remote player. See RouteMediaPlayer for a remote player.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_VOLUME_ADJUST_VOLUME = 30001;
+
+    static {
+        VERSION_VOLUME_COMMANDS_MAP.put(COMMAND_VERSION_1,
+                new Range(COMMAND_CODE_VOLUME_SET_VOLUME,
+                        COMMAND_CODE_VOLUME_ADJUST_VOLUME));
+    }
+
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    // Session commands (i.e. commands to {@link MediaSession2#Session2Callback})
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    static final ArrayMap<Integer, Range> VERSION_SESSION_COMMANDS_MAP = new ArrayMap<>();
+
+    /**
+     * Command code for {@link MediaController2#fastForward()}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_SESSION_FAST_FORWARD = 40000;
+
+    /**
+     * Command code for {@link MediaController2#rewind()}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_SESSION_REWIND = 40001;
+
+    /**
+     * Command code for {@link MediaController2#skipForward()}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_SESSION_SKIP_FORWARD = 40002;
+
+    /**
+     * Command code for {@link MediaController2#skipBackward()}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_SESSION_SKIP_BACKWARD = 40003;
+
+    /**
+     * Command code for {@link MediaController2#setRating(String, Rating)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_SESSION_SET_RATING = 40010;
+
+    public static final Parcelable.Creator<Session2Command> CREATOR =
+            new Parcelable.Creator<Session2Command>() {
+                @Override
+                public Session2Command createFromParcel(Parcel in) {
+                    return new Session2Command(in);
+                }
+
+                @Override
+                public Session2Command[] newArray(int size) {
+                    return new Session2Command[size];
+                }
+            };
+
+    static {
+        VERSION_SESSION_COMMANDS_MAP.put(COMMAND_VERSION_1,
+                new Range(COMMAND_CODE_SESSION_FAST_FORWARD, COMMAND_CODE_SESSION_SET_RATING));
+    }
+
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    // Session commands (i.e. commands to {@link MediaLibrarySession#MediaLibrarySessionCallback})
+    ////////////////////////////////////////////////////////////////////////////////////////////////
+    static final ArrayMap<Integer, Range> VERSION_LIBRARY_COMMANDS_MAP = new ArrayMap<>();
+
+    /**
+     * Command code for {@link MediaBrowser2#getLibraryRoot(Library2Params)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_LIBRARY_GET_LIBRARY_ROOT = 50000;
+
+    /**
+     * Command code for {@link MediaBrowser2#subscribe(String, Library2Params)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_LIBRARY_SUBSCRIBE = 50001;
+
+    /**
+     * Command code for {@link MediaBrowser2#unsubscribe(String)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_LIBRARY_UNSUBSCRIBE = 50002;
+
+    /**
+     * Command code for {@link MediaBrowser2#getChildren(String, int, int, Library2Params)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_LIBRARY_GET_CHILDREN = 50003;
+
+    /**
+     * Command code for {@link MediaBrowser2#getItem(String)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_LIBRARY_GET_ITEM = 50004;
+
+    /**
+     * Command code for {@link MediaBrowser2#search(String, LibraryParams)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_LIBRARY_SEARCH = 50005;
+
+    /**
+     * Command code for {@link MediaBrowser2#getSearchResult(String, int, int, Library2Params)}.
+     * <p>
+     * Code version is {@link #COMMAND_VERSION_1}.
+     */
+    public static final int COMMAND_CODE_LIBRARY_GET_SEARCH_RESULT = 50006;
+
+    static {
+        VERSION_LIBRARY_COMMANDS_MAP.put(COMMAND_VERSION_1,
+                new Range(COMMAND_CODE_LIBRARY_GET_LIBRARY_ROOT,
+                        COMMAND_CODE_LIBRARY_GET_SEARCH_RESULT));
+    }
+
+    @CommandCode private final int mCommandCode;
+    // Nonnull if it's custom command
+    private final String mCustomCommand;
+    private final Bundle mExtras;
+
+    /**
+     * Constructor for creating a predefined command.
+     *
+     * @param commandCode A command code for predefined command.
+     */
+    public Session2Command(@CommandCode int commandCode) {
+        if (commandCode == COMMAND_CODE_CUSTOM) {
+            throw new IllegalArgumentException("commandCode shouldn't be COMMAND_CODE_CUSTOM");
+        }
+        mCommandCode = commandCode;
+        mCustomCommand = null;
+        mExtras = null;
+    }
+
+    /**
+     * Constructor for creating a custom command.
+     *
+     * @param action The action of this custom command.
+     * @param extras An extra bundle for this custom command.
+     */
+    public Session2Command(@NonNull String action, @Nullable Bundle extras) {
+        if (action == null) {
+            throw new IllegalArgumentException("action shouldn't be null");
+        }
+        mCommandCode = COMMAND_CODE_CUSTOM;
+        mCustomCommand = action;
+        mExtras = extras;
+    }
+
+    /**
+     * Used by parcelable creator.
+     */
+    @SuppressWarnings("WeakerAccess") /* synthetic access */
+    Session2Command(Parcel in) {
+        mCommandCode = in.readInt();
+        mCustomCommand = in.readString();
+        mExtras = in.readBundle();
+    }
+
+    /**
+     * Gets the command code of a predefined command.
+     * This will return {@link #COMMAND_CODE_CUSTOM} for a custom command.
+     */
+    public @CommandCode int getCommandCode() {
+        return mCommandCode;
+    }
+
+    /**
+     * Gets the action of a custom command.
+     * This will return {@code null} for a predefined command.
+     */
+    public @Nullable String getCustomCommand() {
+        return mCustomCommand;
+    }
+
+    /**
+     * Gets the extra bundle of a custom command.
+     * This will return {@code null} for a predefined command.
+     */
+    public @Nullable Bundle getExtras() {
+        return mExtras;
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeInt(mCommandCode);
+        dest.writeString(mCustomCommand);
+        dest.writeBundle(mExtras);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof Session2Command)) {
+            return false;
+        }
+        Session2Command other = (Session2Command) obj;
+        return mCommandCode == other.mCommandCode
+                && TextUtils.equals(mCustomCommand, other.mCustomCommand);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(mCustomCommand, mCommandCode);
+    }
+
+    @SuppressWarnings("WeakerAccess") /* synthetic access */
+    static final class Range {
+        public final int lower;
+        public final int upper;
+
+        Range(int lower, int upper) {
+            this.lower = lower;
+            this.upper = upper;
+        }
+    }
+}
+
diff --git a/media/java/android/media/Session2CommandGroup.java b/media/java/android/media/Session2CommandGroup.java
new file mode 100644
index 000000000000..de34fe5c8a2a
--- /dev/null
+++ b/media/java/android/media/Session2CommandGroup.java
@@ -0,0 +1,321 @@
+/*
+ * Copyright 2018 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 android.media;
+
+import static android.media.Session2Command.COMMAND_CODE_CUSTOM;
+import static android.media.Session2Command.COMMAND_VERSION_1;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.media.Session2Command.Range;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.util.ArrayMap;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * A set of {@link Session2Command} which represents a command group.
+ * <p>
+ * This API is not generally intended for third party application developers.
+ * Use the <a href="{@docRoot}tools/extras/support-library.html">Support Library</a>
+ * {@link androidx.media2.SessionCommandGroup} for consistent behavior across all devices.
+ * </p>
+ * @hide
+ */
+public final class Session2CommandGroup implements Parcelable {
+    private static final String TAG = "Session2CommandGroup";
+
+    public static final Parcelable.Creator<Session2CommandGroup> CREATOR =
+            new Parcelable.Creator<Session2CommandGroup>() {
+                @Override
+                public Session2CommandGroup createFromParcel(Parcel in) {
+                    return new Session2CommandGroup(in);
+                }
+
+                @Override
+                public Session2CommandGroup[] newArray(int size) {
+                    return new Session2CommandGroup[size];
+                }
+            };
+
+    Set<Session2Command> mCommands = new HashSet<>();
+
+    /**
+     * Default Constructor.
+     */
+    public Session2CommandGroup() { }
+
+    /**
+     * Creates a new Session2CommandGroup with commands copied from another object.
+     *
+     * @param commands The collection of commands to copy.
+     */
+    public Session2CommandGroup(@Nullable Collection<Session2Command> commands) {
+        if (commands != null) {
+            mCommands.addAll(commands);
+        }
+    }
+
+    /**
+     * Used by parcelable creator.
+     */
+    @SuppressWarnings("WeakerAccess") /* synthetic access */
+    Session2CommandGroup(Parcel in) {
+        Session2Command[] commands = in.readParcelableArray(
+                Session2Command.class.getClassLoader(), Session2Command.class);
+        if (commands != null) {
+            for (Session2Command command : commands) {
+                mCommands.add(command);
+            }
+        }
+    }
+
+    /**
+     * Adds a command to this command group.
+     *
+     * @param command A command to add. Shouldn't be {@code null}.
+     * @hide TODO remove this method
+     */
+    public void addCommand(@NonNull Session2Command command) {
+        if (command == null) {
+            throw new IllegalArgumentException("command shouldn't be null");
+        }
+        if (!hasCommand(command)) {
+            mCommands.add(command);
+        }
+    }
+
+    /**
+     * Adds a predefined command with given {@code commandCode} to this command group.
+     *
+     * @param commandCode A command code to add.
+     *                    Shouldn't be {@link Session2Command#COMMAND_CODE_CUSTOM}.
+     * @hide TODO remove this method
+     */
+    public void addCommand(@Session2Command.CommandCode int commandCode) {
+        if (commandCode == COMMAND_CODE_CUSTOM) {
+            throw new IllegalArgumentException(
+                    "Use addCommand(Session2Command) for COMMAND_CODE_CUSTOM.");
+        }
+        if (!hasCommand(commandCode)) {
+            mCommands.add(new Session2Command(commandCode));
+        }
+    }
+
+    /**
+     * Checks whether this command group has a command that matches given {@code command}.
+     *
+     * @param command A command to find. Shouldn't be {@code null}.
+     */
+    public boolean hasCommand(@NonNull Session2Command command) {
+        if (command == null) {
+            throw new IllegalArgumentException("command shouldn't be null");
+        }
+        return mCommands.contains(command);
+    }
+
+    /**
+     * Checks whether this command group has a command that matches given {@code commandCode}.
+     *
+     * @param commandCode A command code to find.
+     *                    Shouldn't be {@link Session2Command#COMMAND_CODE_CUSTOM}.
+     */
+    public boolean hasCommand(@Session2Command.CommandCode int commandCode) {
+        if (commandCode == COMMAND_CODE_CUSTOM) {
+            throw new IllegalArgumentException("Use hasCommand(Command) for custom command");
+        }
+        for (Session2Command command : mCommands) {
+            if (command.getCommandCode() == commandCode) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Gets all commands of this command group.
+     */
+    public @NonNull Set<Session2Command> getCommands() {
+        return new HashSet<>(mCommands);
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeParcelableArray((Session2Command[]) mCommands.toArray(), 0);
+    }
+
+    /**
+     * Builds a {@link Session2CommandGroup} object.
+     */
+    public static final class Builder {
+        private Set<Session2Command> mCommands;
+
+        public Builder() {
+            mCommands = new HashSet<>();
+        }
+
+        /**
+         * Creates a new builder for {@link Session2CommandGroup} with commands copied from another
+         * {@link Session2CommandGroup} object.
+         * @param commandGroup
+         */
+        public Builder(@NonNull Session2CommandGroup commandGroup) {
+            mCommands = commandGroup.getCommands();
+        }
+
+        /**
+         * Adds a command to this command group.
+         *
+         * @param command A command to add. Shouldn't be {@code null}.
+         */
+        public @NonNull Builder addCommand(@NonNull Session2Command command) {
+            if (command == null) {
+                throw new IllegalArgumentException("command shouldn't be null");
+            }
+            mCommands.add(command);
+            return this;
+        }
+
+        /**
+         * Adds a predefined command with given {@code commandCode} to this command group.
+         *
+         * @param commandCode A command code to add.
+         *                    Shouldn't be {@link Session2Command#COMMAND_CODE_CUSTOM}.
+         */
+        public @NonNull Builder addCommand(@Session2Command.CommandCode int commandCode) {
+            if (commandCode == COMMAND_CODE_CUSTOM) {
+                throw new IllegalArgumentException(
+                        "Use addCommand(Session2Command) for COMMAND_CODE_CUSTOM.");
+            }
+            mCommands.add(new Session2Command(commandCode));
+            return this;
+        }
+
+        /**
+         * Adds all predefined session commands except for the commands added after the specified
+         * version without default implementation. This provides convenient way to add commands
+         * with implementation.
+         *
+         * @param version command version
+         * @see Session2Command#COMMAND_VERSION_1
+         * @see
+         * MediaSession2.Session2Callback#onConnect
+         */
+        public @NonNull Builder addAllPredefinedCommands(
+                @Session2Command.CommandVersion int version) {
+            if (version != COMMAND_VERSION_1) {
+                throw new IllegalArgumentException("Unknown command version " + version);
+            }
+            addAllPlayerCommands(version);
+            addAllVolumeCommands(version);
+            addAllSessionCommands(version);
+            addAllLibraryCommands(version);
+            return this;
+        }
+
+        /**
+         * Removes a command from this group which matches given {@code command}.
+         *
+         * @param command A command to find. Shouldn't be {@code null}.
+         */
+        public @NonNull Builder removeCommand(@NonNull Session2Command command) {
+            if (command == null) {
+                throw new IllegalArgumentException("command shouldn't be null");
+            }
+            mCommands.remove(command);
+            return this;
+        }
+
+        /**
+         * Removes a command from this group which matches given {@code commandCode}.
+         *
+         * @param commandCode A command code to find.
+         *                    Shouldn't be {@link Session2Command#COMMAND_CODE_CUSTOM}.
+         */
+        public @NonNull Builder removeCommand(@Session2Command.CommandCode int commandCode) {
+            if (commandCode == COMMAND_CODE_CUSTOM) {
+                throw new IllegalArgumentException("commandCode shouldn't be COMMAND_CODE_CUSTOM");
+            }
+            mCommands.remove(new Session2Command(commandCode));
+            return this;
+        }
+
+        @NonNull Builder addAllPlayerCommands(@Session2Command.CommandVersion int version) {
+            addCommands(version, Session2Command.VERSION_PLAYER_COMMANDS_MAP);
+            return this;
+        }
+
+        @NonNull Builder addAllPlayerCommands(@Session2Command.CommandVersion int version,
+                boolean includePlaylistCommands) {
+            if (includePlaylistCommands) {
+                return addAllPlayerCommands(version);
+            }
+            for (int i = COMMAND_VERSION_1; i <= version; i++) {
+                Range include = Session2Command.VERSION_PLAYER_COMMANDS_MAP.get(i);
+                Range exclude = Session2Command.VERSION_PLAYER_PLAYLIST_COMMANDS_MAP.get(i);
+                for (int code = include.lower; code <= include.upper; code++) {
+                    if (code < exclude.lower && code > exclude.upper) {
+                        addCommand(code);
+                    }
+                }
+            }
+            return this;
+        }
+
+        @NonNull Builder addAllVolumeCommands(@Session2Command.CommandVersion int version) {
+            addCommands(version, Session2Command.VERSION_VOLUME_COMMANDS_MAP);
+            return this;
+        }
+
+        @NonNull Builder addAllSessionCommands(@Session2Command.CommandVersion int version) {
+            addCommands(version, Session2Command.VERSION_SESSION_COMMANDS_MAP);
+            return this;
+        }
+
+        @NonNull Builder addAllLibraryCommands(@Session2Command.CommandVersion int version) {
+            addCommands(version, Session2Command.VERSION_LIBRARY_COMMANDS_MAP);
+            return this;
+        }
+
+        private void addCommands(
+                @Session2Command.CommandVersion int version, ArrayMap<Integer, Range> map) {
+            for (int i = COMMAND_VERSION_1; i <= version; i++) {
+                Range range = map.get(i);
+                for (int code = range.lower; code <= range.upper; code++) {
+                    addCommand(code);
+                }
+            }
+        }
+
+        /**
+         * Builds {@link Session2CommandGroup}.
+         *
+         * @return a new {@link Session2CommandGroup}.
+         */
+        public @NonNull Session2CommandGroup build() {
+            return new Session2CommandGroup(mCommands);
+        }
+    }
+}