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      1 /*
      2  * Copyright (C) 2012 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.internal.os;
     18 
     19 /**
     20  * Helper class for passing more arguments though a message
     21  * and avoiding allocation of a custom class for wrapping the
     22  * arguments. This class maintains a pool of instances and
     23  * it is responsibility of the client to recycle and instance
     24  * once it is no longer used.
     25  */
     26 public final class SomeArgs {
     27 
     28     private static final int MAX_POOL_SIZE = 10;
     29 
     30     private static SomeArgs sPool;
     31     private static int sPoolSize;
     32     private static Object sPoolLock = new Object();
     33 
     34     private SomeArgs mNext;
     35 
     36     private boolean mInPool;
     37 
     38     public Object arg1;
     39     public Object arg2;
     40     public Object arg3;
     41     public Object arg4;
     42     public Object arg5;
     43     public int argi1;
     44     public int argi2;
     45     public int argi3;
     46     public int argi4;
     47     public int argi5;
     48     public int argi6;
     49 
     50     private SomeArgs() {
     51         /* do nothing - reduce visibility */
     52     }
     53 
     54     public static SomeArgs obtain() {
     55         synchronized (sPoolLock) {
     56             if (sPoolSize > 0) {
     57                 SomeArgs args = sPool;
     58                 sPool = sPool.mNext;
     59                 args.mNext = null;
     60                 args.mInPool = false;
     61                 sPoolSize--;
     62                 return args;
     63             } else {
     64                 return new SomeArgs();
     65             }
     66         }
     67     }
     68 
     69     public void recycle() {
     70         if (mInPool) {
     71             throw new IllegalStateException("Already recycled.");
     72         }
     73         synchronized (sPoolLock) {
     74             clear();
     75             if (sPoolSize < MAX_POOL_SIZE) {
     76                 mNext = sPool;
     77                 mInPool = true;
     78                 sPool = this;
     79                 sPoolSize++;
     80             }
     81         }
     82     }
     83 
     84     private void clear() {
     85         arg1 = null;
     86         arg2 = null;
     87         arg3 = null;
     88         arg4 = null;
     89         arg5 = null;
     90         argi1 = 0;
     91         argi2 = 0;
     92         argi3 = 0;
     93         argi4 = 0;
     94         argi5 = 0;
     95         argi6 = 0;
     96     }
     97 }
     98