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/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.view.accessibility;
import android.util.SparseArray;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
final class WeakSparseArray<E> {
private final ReferenceQueue<E> mRefQueue = new ReferenceQueue<>();
private final SparseArray<WeakReferenceWithId<E>> mSparseArray = new SparseArray<>();
public void append(int key, E value) {
removeUnreachableValues();
mSparseArray.append(key, new WeakReferenceWithId(value, mRefQueue, key));
}
public void remove(int key) {
removeUnreachableValues();
mSparseArray.remove(key);
}
public E get(int key) {
removeUnreachableValues();
WeakReferenceWithId<E> ref = mSparseArray.get(key);
return ref != null ? ref.get() : null;
}
private void removeUnreachableValues() {
for (Reference ref = mRefQueue.poll(); ref != null; ref = mRefQueue.poll()) {
mSparseArray.remove(((WeakReferenceWithId) ref).mId);
}
}
private static class WeakReferenceWithId<E> extends WeakReference<E> {
final int mId;
WeakReferenceWithId(E referent, ReferenceQueue<? super E> q, int id) {
super(referent, q);
mId = id;
}
}
}
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