1 /* 2 * Copyright (C) 2024 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.car.internal.common; 18 19 import android.car.builtin.util.Slogf; 20 import android.util.ArrayMap; 21 import android.util.Log; 22 23 import java.util.ArrayList; 24 import java.util.List; 25 26 /** 27 * A dispatch list that stores events for each client and then dispatch them to each client. 28 * 29 * This class is not thread-safe. 30 * 31 * Subclass must override {@code dispatchToClient}. 32 * 33 * @param <ClientType> The type for the client. 34 * @param <EventType> The type for the event. 35 */ 36 public abstract class DispatchList<ClientType, EventType> { 37 private static final String TAG = "DispatchList"; 38 private static final boolean DBG = Log.isLoggable(TAG, Log.DEBUG); 39 40 private ArrayMap<ClientType, List<EventType>> mEventsByClient = new ArrayMap<>(); 41 42 /** 43 * Dispatch events to one client. 44 * 45 * Must be implemented by subclass. 46 */ dispatchToClient(ClientType client, List<EventType> events)47 protected abstract void dispatchToClient(ClientType client, List<EventType> events); 48 49 /** 50 * Adds an event to be dispatched to a client. 51 */ addEvent(ClientType client, EventType event)52 public void addEvent(ClientType client, EventType event) { 53 if (DBG) { 54 Slogf.d(TAG, "addEvent with client: %s, event: %s", client, event); 55 } 56 var eventsToNotify = mEventsByClient.get(client); 57 if (eventsToNotify == null) { 58 eventsToNotify = new ArrayList<EventType>(); 59 mEventsByClient.put(client, eventsToNotify); 60 } 61 eventsToNotify.add(event); 62 } 63 64 /** 65 * Adds events to be dispatched to a client. 66 */ addEvents(ClientType client, List<EventType> events)67 public void addEvents(ClientType client, List<EventType> events) { 68 if (DBG) { 69 Slogf.d(TAG, "addEvent with client: %s, events: %s", client, events); 70 } 71 var eventsToNotify = mEventsByClient.get(client); 72 if (eventsToNotify == null) { 73 eventsToNotify = new ArrayList<EventType>(); 74 mEventsByClient.put(client, eventsToNotify); 75 } 76 eventsToNotify.addAll(events); 77 } 78 79 /** 80 * Dispatches all the added events to clients. 81 * 82 * This clears all the added events after dispatching. 83 */ dispatchToClients()84 public void dispatchToClients() { 85 for (int i = 0; i < mEventsByClient.size(); i++) { 86 if (DBG) { 87 Slogf.d(TAG, "dispatch to client: %s, events: %s", 88 mEventsByClient.valueAt(i), mEventsByClient.valueAt(i)); 89 } 90 91 dispatchToClient(mEventsByClient.keyAt(i), mEventsByClient.valueAt(i)); 92 } 93 mEventsByClient.clear(); 94 } 95 } 96