| /* |
| * Copyright 2017 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.app.servertransaction; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * An object pool that can provide reused objects if available. |
| * @hide |
| */ |
| class ObjectPool { |
| |
| private static final Object sPoolSync = new Object(); |
| private static final Map<Class, ArrayList<? extends ObjectPoolItem>> sPoolMap = |
| new HashMap<>(); |
| |
| private static final int MAX_POOL_SIZE = 50; |
| |
| /** |
| * Obtain an instance of a specific class from the pool |
| * @param itemClass The class of the object we're looking for. |
| * @return An instance or null if there is none. |
| */ |
| public static <T extends ObjectPoolItem> T obtain(Class<T> itemClass) { |
| synchronized (sPoolSync) { |
| @SuppressWarnings("unchecked") |
| final ArrayList<T> itemPool = (ArrayList<T>) sPoolMap.get(itemClass); |
| if (itemPool != null && !itemPool.isEmpty()) { |
| return itemPool.remove(itemPool.size() - 1); |
| } |
| return null; |
| } |
| } |
| |
| /** |
| * Recycle the object to the pool. The object should be properly cleared before this. |
| * @param item The object to recycle. |
| * @see ObjectPoolItem#recycle() |
| */ |
| public static <T extends ObjectPoolItem> void recycle(T item) { |
| synchronized (sPoolSync) { |
| @SuppressWarnings("unchecked") |
| ArrayList<T> itemPool = (ArrayList<T>) sPoolMap.get(item.getClass()); |
| if (itemPool == null) { |
| itemPool = new ArrayList<>(); |
| sPoolMap.put(item.getClass(), itemPool); |
| } |
| // Check if the item is already in the pool |
| final int size = itemPool.size(); |
| for (int i = 0; i < size; i++) { |
| if (itemPool.get(i) == item) { |
| throw new IllegalStateException("Trying to recycle already recycled item"); |
| } |
| } |
| |
| if (size < MAX_POOL_SIZE) { |
| itemPool.add(item); |
| } |
| } |
| } |
| } |