1 /*
2  * Copyright (C) 2017 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 
17 package com.android.systemui.keyguard;
18 
19 import androidx.annotation.NonNull;
20 
21 import java.util.ArrayList;
22 import java.util.Objects;
23 import java.util.function.BiConsumer;
24 import java.util.function.Consumer;
25 
26 /**
27  * Base class for lifecycles with observers.
28  */
29 public class Lifecycle<T> {
30 
31     private ArrayList<T> mObservers = new ArrayList<>();
32 
addObserver(@onNull T observer)33     public void addObserver(@NonNull T observer) {
34         mObservers.add(Objects.requireNonNull(observer));
35     }
36 
removeObserver(T observer)37     public void removeObserver(T observer) {
38         mObservers.remove(observer);
39     }
40 
dispatch(Consumer<T> consumer)41     public void dispatch(Consumer<T> consumer) {
42         for (int i = 0; i < mObservers.size(); i++) {
43             consumer.accept(mObservers.get(i));
44         }
45     }
46 
47     /**
48      * Will dispatch the consumer to the observer, along with a single argument of type<U>.
49      */
dispatch(BiConsumer<T, U> biConsumer, U arg)50     public <U> void dispatch(BiConsumer<T, U> biConsumer, U arg) {
51         for (int i = 0; i < mObservers.size(); i++) {
52             biConsumer.accept(mObservers.get(i), arg);
53         }
54     }
55 }
56