56 lines
2.1 KiB
Java
56 lines
2.1 KiB
Java
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.database;
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/**
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* A specialization of {@link Observable} for {@link DataSetObserver}
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* that provides methods for sending notifications to a list of
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* {@link DataSetObserver} objects.
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*/
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@android.ravenwood.annotation.RavenwoodKeepWholeClass
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public class DataSetObservable extends Observable<DataSetObserver> {
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/**
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* Invokes {@link DataSetObserver#onChanged} on each observer.
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* Called when the contents of the data set have changed. The recipient
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* will obtain the new contents the next time it queries the data set.
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*/
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public void notifyChanged() {
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synchronized(mObservers) {
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// since onChanged() is implemented by the app, it could do anything, including
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// removing itself from {@link mObservers} - and that could cause problems if
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// an iterator is used on the ArrayList {@link mObservers}.
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// to avoid such problems, just march thru the list in the reverse order.
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for (int i = mObservers.size() - 1; i >= 0; i--) {
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mObservers.get(i).onChanged();
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}
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}
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}
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/**
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* Invokes {@link DataSetObserver#onInvalidated} on each observer.
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* Called when the data set is no longer valid and cannot be queried again,
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* such as when the data set has been closed.
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*/
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public void notifyInvalidated() {
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synchronized (mObservers) {
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for (int i = mObservers.size() - 1; i >= 0; i--) {
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mObservers.get(i).onInvalidated();
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}
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}
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}
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}
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