1 /* 2 * Copyright (C) 2018 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.server.wm; 18 19 import android.annotation.NonNull; 20 21 /** 22 * Multi-cast delegate implementation for {@link ActivityMetricsLaunchObserver}. 23 * 24 * <br/><br/> 25 * This enables multiple launch observers to subscribe to {@link ActivityMetricsLogger} 26 * independently of each other. 27 * 28 * <br/><br/> 29 * Some callbacks in {@link ActivityMetricsLaunchObserver} have a {@code byte[]} 30 * parameter; this array is reused by all the registered observers, so it must not be written to 31 * (i.e. all observers must treat any array parameters as immutable). 32 * 33 * <br /><br /> 34 * Multi-cast invocations occurs sequentially in-order of registered observers. 35 */ 36 public interface ActivityMetricsLaunchObserverRegistry { 37 /** 38 * Register an extra launch observer to receive the multi-cast. 39 * 40 * <br /><br /> 41 * Multi-cast invocation happens in the same order the observers were registered. For example, 42 * <pre> 43 * registerLaunchObserver(A) 44 * registerLaunchObserver(B) 45 * 46 * obs.onIntentFailed() -> 47 * A.onIntentFailed() 48 * B.onIntentFailed() 49 * </pre> 50 */ registerLaunchObserver(@onNull ActivityMetricsLaunchObserver launchObserver)51 void registerLaunchObserver(@NonNull ActivityMetricsLaunchObserver launchObserver); 52 53 /** 54 * Unregister an existing launch observer. It will not receive the multi-cast in the future. 55 * 56 * <br /><br /> 57 * This does nothing if this observer was not already registered. 58 */ unregisterLaunchObserver(@onNull ActivityMetricsLaunchObserver launchObserver)59 void unregisterLaunchObserver(@NonNull ActivityMetricsLaunchObserver launchObserver); 60 } 61