19066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project/* 29066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Copyright (C) 2007 The Android Open Source Project 39066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 49066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Licensed under the Apache License, Version 2.0 (the "License"); 59066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * you may not use this file except in compliance with the License. 69066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * You may obtain a copy of the License at 79066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 89066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 99066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 109066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 119066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 129066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 139066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * See the License for the specific language governing permissions and 149066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * limitations under the License. 159066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 169066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 179066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectpackage android.database; 189066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 199066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectimport java.util.ArrayList; 209066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 219066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project/** 2286de0590b94bcce27e3038c27464bed510bb564aJeff Brown * Provides methods for registering or unregistering arbitrary observers in an {@link ArrayList}. 2386de0590b94bcce27e3038c27464bed510bb564aJeff Brown * 2486de0590b94bcce27e3038c27464bed510bb564aJeff Brown * This abstract class is intended to be subclassed and specialized to maintain 2586de0590b94bcce27e3038c27464bed510bb564aJeff Brown * a registry of observers of specific types and dispatch notifications to them. 2686de0590b94bcce27e3038c27464bed510bb564aJeff Brown * 2786de0590b94bcce27e3038c27464bed510bb564aJeff Brown * @param T The observer type. 289066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 299066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectpublic abstract class Observable<T> { 309066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 319066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * The list of observers. An observer can be in the list at most 329066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * once and will never be null. 339066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 349066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project protected final ArrayList<T> mObservers = new ArrayList<T>(); 359066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 369066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 379066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Adds an observer to the list. The observer cannot be null and it must not already 389066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * be registered. 399066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * @param observer the observer to register 409066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * @throws IllegalArgumentException the observer is null 419066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * @throws IllegalStateException the observer is already registered 429066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 439066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public void registerObserver(T observer) { 449066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project if (observer == null) { 459066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project throw new IllegalArgumentException("The observer is null."); 469066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 479066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project synchronized(mObservers) { 489066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project if (mObservers.contains(observer)) { 499066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project throw new IllegalStateException("Observer " + observer + " is already registered."); 509066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 519066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project mObservers.add(observer); 529066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 539066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 549066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 559066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 569066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Removes a previously registered observer. The observer must not be null and it 579066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * must already have been registered. 589066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * @param observer the observer to unregister 599066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * @throws IllegalArgumentException the observer is null 609066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * @throws IllegalStateException the observer is not yet registered 619066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 629066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public void unregisterObserver(T observer) { 639066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project if (observer == null) { 649066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project throw new IllegalArgumentException("The observer is null."); 659066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 669066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project synchronized(mObservers) { 679066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project int index = mObservers.indexOf(observer); 689066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project if (index == -1) { 699066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project throw new IllegalStateException("Observer " + observer + " was not registered."); 709066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 719066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project mObservers.remove(index); 729066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 739066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 7486de0590b94bcce27e3038c27464bed510bb564aJeff Brown 759066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 7686de0590b94bcce27e3038c27464bed510bb564aJeff Brown * Remove all registered observers. 779066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 789066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public void unregisterAll() { 799066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project synchronized(mObservers) { 809066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project mObservers.clear(); 8186de0590b94bcce27e3038c27464bed510bb564aJeff Brown } 829066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 839066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project} 84