1 /*
2  * Copyright (C) 2016 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 package com.android.car.apps.common;
17 
18 /**
19  * @hide
20  */
21 public class RefcountObject<T> {
22 
23     public interface RefcountListener {
onRefcountZero(RefcountObject<?> object)24         void onRefcountZero(RefcountObject<?> object);
25     }
26 
27     private RefcountObject.RefcountListener mRefcountListener;
28     private int mRefcount;
29     private T mObject;
30 
RefcountObject(T object)31     public RefcountObject(T object) {
32         mObject = object;
33     }
34 
setRefcountListener(RefcountObject.RefcountListener listener)35     public void setRefcountListener(RefcountObject.RefcountListener listener) {
36         mRefcountListener = listener;
37     }
38 
addRef()39     public synchronized int addRef() {
40         mRefcount++;
41         return mRefcount;
42     }
43 
releaseRef()44     public synchronized int releaseRef() {
45         mRefcount--;
46         if (mRefcount == 0 && mRefcountListener != null) {
47             mRefcountListener.onRefcountZero(this);
48         }
49         return mRefcount;
50     }
51 
getRef()52     public synchronized int getRef() {
53         return mRefcount;
54     }
55 
getObject()56     public T getObject() {
57         return mObject;
58     }
59 }
60