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    static final int WAIT_NONE = 0;
39    static final int WAIT_WAITING = 1;
40    static final int WAIT_FINISHED = 2;
41    int mWaitState = WAIT_NONE;
42
43    public Object arg1;
44    public Object arg2;
45    public Object arg3;
46    public Object arg4;
47    public Object arg5;
48    public Object arg6;
49    public Object arg7;
50    public Object arg8;
51    public int argi1;
52    public int argi2;
53    public int argi3;
54    public int argi4;
55    public int argi5;
56    public int argi6;
57
58    private SomeArgs() {
59        /* do nothing - reduce visibility */
60    }
61
62    public static SomeArgs obtain() {
63        synchronized (sPoolLock) {
64            if (sPoolSize > 0) {
65                SomeArgs args = sPool;
66                sPool = sPool.mNext;
67                args.mNext = null;
68                args.mInPool = false;
69                sPoolSize--;
70                return args;
71            } else {
72                return new SomeArgs();
73            }
74        }
75    }
76
77    public void complete() {
78        synchronized (this) {
79            if (mWaitState != WAIT_WAITING) {
80                throw new IllegalStateException("Not waiting");
81            }
82            mWaitState = WAIT_FINISHED;
83            notifyAll();
84        }
85    }
86
87    public void recycle() {
88        if (mInPool) {
89            throw new IllegalStateException("Already recycled.");
90        }
91        if (mWaitState != WAIT_NONE) {
92            return;
93        }
94        synchronized (sPoolLock) {
95            clear();
96            if (sPoolSize < MAX_POOL_SIZE) {
97                mNext = sPool;
98                mInPool = true;
99                sPool = this;
100                sPoolSize++;
101            }
102        }
103    }
104
105    private void clear() {
106        arg1 = null;
107        arg2 = null;
108        arg3 = null;
109        arg4 = null;
110        arg5 = null;
111        arg6 = null;
112        arg7 = null;
113        argi1 = 0;
114        argi2 = 0;
115        argi3 = 0;
116        argi4 = 0;
117        argi5 = 0;
118        argi6 = 0;
119    }
120}
121