1 /* 2 * Copyright (C) 2015 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 com.android.camera.processing.memory; 18 19 import com.android.camera.async.SafeCloseable; 20 21 import javax.annotation.Nullable; 22 23 /** 24 * Pool for and/or creating or reusing expensive resources. 25 */ 26 public interface LruResourcePool<TKey, TValue> { 27 /** 28 * Returns a wrapped reference to a resource. 29 * 30 * @param key size of memory. 31 * @return T object representing a reusable n-bytes of memory. 32 */ acquire(TKey key)33 public Resource<TValue> acquire(TKey key); 34 35 /** 36 * Closeable resource object that will release the underlying object back to the 37 * source resource pool. A resource may be released or closed multiple times, 38 * and calls to get will return null if the resource has already been released. 39 */ 40 public interface Resource<T> extends SafeCloseable { 41 /** 42 * Get the underlying resource. This will return null if the resource has been 43 * closed and returned to the pool. 44 * 45 * @return the resource represented by this instance. 46 */ 47 @Nullable get()48 public T get(); 49 } 50 } 51