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 17 package androidx.window.util; 18 19 import androidx.annotation.NonNull; 20 21 import java.util.LinkedHashSet; 22 import java.util.Set; 23 24 /** 25 * Base class that provides the implementation for the callback mechanism of the 26 * {@link DataProducer} API. 27 * 28 * @param <T> The type of data this producer returns through {@link #getData()}. 29 */ 30 public abstract class BaseDataProducer<T> implements DataProducer<T> { 31 private final Set<Runnable> mCallbacks = new LinkedHashSet<>(); 32 33 @Override addDataChangedCallback(@onNull Runnable callback)34 public final void addDataChangedCallback(@NonNull Runnable callback) { 35 mCallbacks.add(callback); 36 } 37 38 @Override removeDataChangedCallback(@onNull Runnable callback)39 public final void removeDataChangedCallback(@NonNull Runnable callback) { 40 mCallbacks.remove(callback); 41 } 42 43 /** 44 * Called to notify all registered callbacks that the data provided by {@link #getData()} has 45 * changed. 46 */ notifyDataChanged()47 protected void notifyDataChanged() { 48 for (Runnable callback : mCallbacks) { 49 callback.run(); 50 } 51 } 52 } 53