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 com.android.app.tracing.TraceUtils; 22 23 import kotlin.Unit; 24 25 import java.util.ArrayList; 26 import java.util.Objects; 27 import java.util.function.BiConsumer; 28 import java.util.function.Consumer; 29 30 /** 31 * Base class for lifecycles with observers. 32 */ 33 public class Lifecycle<T> { 34 35 private final ArrayList<T> mObservers = new ArrayList<>(); 36 addObserver(@onNull T observer)37 public void addObserver(@NonNull T observer) { 38 mObservers.add(Objects.requireNonNull(observer)); 39 } 40 removeObserver(T observer)41 public void removeObserver(T observer) { 42 mObservers.remove(observer); 43 } 44 dispatch(Consumer<T> consumer)45 public void dispatch(Consumer<T> consumer) { 46 for (int i = 0; i < mObservers.size(); i++) { 47 final T observer = mObservers.get(i); 48 TraceUtils.trace(() -> "dispatch#" + consumer.toString(), () -> { 49 consumer.accept(observer); 50 return Unit.INSTANCE; 51 }); 52 } 53 } 54 55 /** 56 * Will dispatch the consumer to the observer, along with a single argument of type<U>. 57 */ dispatch(BiConsumer<T, U> biConsumer, U arg)58 public <U> void dispatch(BiConsumer<T, U> biConsumer, U arg) { 59 for (int i = 0; i < mObservers.size(); i++) { 60 final T observer = mObservers.get(i); 61 TraceUtils.trace(() -> "dispatch#" + biConsumer.toString(), () -> { 62 biConsumer.accept(observer, arg); 63 return Unit.INSTANCE; 64 }); 65 } 66 } 67 } 68