1 /*
2  * Copyright (C) 2021 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.android.systemui.flags
17 
18 /**
19  * Plugin for loading flag values
20  */
21 interface FlagReader {
22     /** Returns a boolean value for the given flag.  */
23     fun isEnabled(flag: BooleanFlag): Boolean {
24         return flag.default
25     }
26 
27     /** Returns a boolean value for the given flag.  */
28     fun isEnabled(id: Int, def: Boolean): Boolean {
29         return def
30     }
31 
32     /** Add a listener to be alerted when any flag changes.  */
33     fun addListener(listener: Listener) {}
34 
35     /** Remove a listener to be alerted when any flag changes.  */
36     fun removeListener(listener: Listener) {}
37 
38     /** A simple listener to be alerted when a flag changes.  */
39     fun interface Listener {
40         /**  */
41         fun onFlagChanged(id: Int)
42     }
43 }