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
17package 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 */
26public 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 int argi1;
43    public int argi2;
44    public int argi3;
45    public int argi4;
46    public int argi5;
47    public int argi6;
48
49    private SomeArgs() {
50        /* do nothing - reduce visibility */
51    }
52
53    public static SomeArgs obtain() {
54        synchronized (sPoolLock) {
55            if (sPoolSize > 0) {
56                SomeArgs args = sPool;
57                sPool = sPool.mNext;
58                args.mNext = null;
59                args.mInPool = false;
60                sPoolSize--;
61                return args;
62            } else {
63                return new SomeArgs();
64            }
65        }
66    }
67
68    public void recycle() {
69        if (mInPool) {
70            throw new IllegalStateException("Already recycled.");
71        }
72        synchronized (sPoolLock) {
73            clear();
74            if (sPoolSize < MAX_POOL_SIZE) {
75                mNext = sPool;
76                mInPool = true;
77                sPool = this;
78                sPoolSize++;
79            }
80        }
81    }
82
83    private void clear() {
84        arg1 = null;
85        arg2 = null;
86        arg3 = null;
87        arg4 = null;
88        argi1 = 0;
89        argi2 = 0;
90        argi3 = 0;
91        argi4 = 0;
92        argi5 = 0;
93        argi6 = 0;
94    }
95}
96