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      1 /*
      2  * Copyright (C) 2009 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 android.util;
     18 
     19 /**
     20  * @hide
     21  */
     22 class FinitePool<T extends Poolable<T>> implements Pool<T> {
     23     private static final String LOG_TAG = "FinitePool";
     24 
     25     /**
     26      * Factory used to create new pool objects
     27      */
     28     private final PoolableManager<T> mManager;
     29     /**
     30      * Maximum number of objects in the pool
     31      */
     32     private final int mLimit;
     33     /**
     34      * If true, mLimit is ignored
     35      */
     36     private final boolean mInfinite;
     37 
     38     /**
     39      * Next object to acquire
     40      */
     41     private T mRoot;
     42     /**
     43      * Number of objects in the pool
     44      */
     45     private int mPoolCount;
     46 
     47     FinitePool(PoolableManager<T> manager) {
     48         mManager = manager;
     49         mLimit = 0;
     50         mInfinite = true;
     51     }
     52 
     53     FinitePool(PoolableManager<T> manager, int limit) {
     54         if (limit <= 0) throw new IllegalArgumentException("The pool limit must be > 0");
     55 
     56         mManager = manager;
     57         mLimit = limit;
     58         mInfinite = false;
     59     }
     60 
     61     public T acquire() {
     62         T element;
     63 
     64         if (mRoot != null) {
     65             element = mRoot;
     66             mRoot = element.getNextPoolable();
     67             mPoolCount--;
     68         } else {
     69             element = mManager.newInstance();
     70         }
     71 
     72         if (element != null) {
     73             element.setNextPoolable(null);
     74             element.setPooled(false);
     75             mManager.onAcquired(element);
     76         }
     77 
     78         return element;
     79     }
     80 
     81     public void release(T element) {
     82         if (!element.isPooled()) {
     83             if (mInfinite || mPoolCount < mLimit) {
     84                 mPoolCount++;
     85                 element.setNextPoolable(mRoot);
     86                 element.setPooled(true);
     87                 mRoot = element;
     88             }
     89             mManager.onReleased(element);
     90         } else {
     91             Log.w(LOG_TAG, "Element is already in pool: " + element);
     92         }
     93     }
     94 }
     95