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bf70dcc3 MG |
1 | package ro.ieval.fonbot; |
2 | ||
3 | import java.util.LinkedList; | |
4 | import java.util.Queue; | |
bf70dcc3 | 5 | import java.util.concurrent.Executors; |
e154bdfd MG |
6 | import java.util.concurrent.ScheduledExecutorService; |
7 | import java.util.concurrent.TimeUnit; | |
8 | ||
9 | import android.os.SystemClock; | |
bf70dcc3 MG |
10 | |
11 | /* | |
12 | * Copyright © 2013 Marius Gavrilescu | |
13 | * | |
14 | * This file is part of FonBot. | |
15 | * | |
16 | * FonBot is free software: you can redistribute it and/or modify | |
17 | * it under the terms of the GNU General Public License as published by | |
18 | * the Free Software Foundation, either version 3 of the License, or | |
19 | * (at your option) any later version. | |
20 | * | |
21 | * FonBot is distributed in the hope that it will be useful, | |
22 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
23 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
24 | * GNU General Public License for more details. | |
25 | * | |
26 | * You should have received a copy of the GNU General Public License | |
27 | * along with FonBot. If not, see <http://www.gnu.org/licenses/>. | |
28 | */ | |
29 | ||
30 | /** | |
31 | * Slim alternative to AsyncTask.<p> | |
32 | * | |
33 | * Differences from AsyncTask: | |
34 | * <ul> | |
35 | * <li>No onPreExecute or onPostExecute | |
36 | * <li>No progress support | |
37 | * <li>Can be retried if necessary | |
38 | * </ul> | |
39 | * | |
40 | * @author Marius Gavrilescu <marius@ieval.ro> | |
41 | */ | |
42 | abstract class ExecutableRunnable implements Runnable { | |
43 | /** Executor used to execute instances of this class */ | |
561cd6dc | 44 | private static final ScheduledExecutorService EXECUTORS = Executors.newSingleThreadScheduledExecutor(); |
bf70dcc3 | 45 | /** Queue containing <code>ExecutableRunnable</code>s that should be retried */ |
561cd6dc | 46 | private static final Queue<ExecutableRunnable> RETRY_PENDING_TASKS = new LinkedList<ExecutableRunnable>(); |
e154bdfd | 47 | /** Minimum interval between task retries, in milliseconds */ |
561cd6dc | 48 | private static final long RETRY_INTERVAL = 30000; |
e154bdfd MG |
49 | /** {@link SystemClock#elapsedRealtime()} time of last successful call to {@link #retryTasks()} */ |
50 | private static long lastRetry = 0; | |
561cd6dc | 51 | /** True if a retryTasks run is already scheduled on {@link #EXECUTORS} */ |
e154bdfd | 52 | private static volatile boolean retryIsScheduled = false; |
bf70dcc3 MG |
53 | |
54 | /** Run all tasks that should be retried */ | |
55 | public static final void retryTasks(){ | |
561cd6dc | 56 | if(!retryIsScheduled && lastRetry+RETRY_INTERVAL>SystemClock.elapsedRealtime()){ |
e154bdfd | 57 | retryIsScheduled = true; |
561cd6dc | 58 | EXECUTORS.schedule(new Runnable() { |
e154bdfd MG |
59 | @Override |
60 | public void run() { | |
61 | retryTasks(); | |
62 | retryIsScheduled = false; | |
63 | } | |
561cd6dc | 64 | }, RETRY_INTERVAL, TimeUnit.MILLISECONDS); |
e154bdfd MG |
65 | return; |
66 | } | |
561cd6dc MG |
67 | synchronized(RETRY_PENDING_TASKS){ |
68 | for(ExecutableRunnable task : RETRY_PENDING_TASKS) | |
69 | EXECUTORS.execute(task); | |
70 | RETRY_PENDING_TASKS.clear(); | |
bf70dcc3 | 71 | } |
e154bdfd | 72 | lastRetry=SystemClock.elapsedRealtime(); |
bf70dcc3 MG |
73 | } |
74 | ||
75 | /** Execute this <code>ExecutableRunnable</code> */ | |
76 | public final void execute(){ | |
77 | retryTasks(); | |
561cd6dc | 78 | EXECUTORS.execute(this); |
bf70dcc3 MG |
79 | } |
80 | ||
81 | /** Mark this <code>ExecutableRunnable</code> as needing to be retried later */ | |
82 | protected final void retry(){ | |
561cd6dc MG |
83 | synchronized(RETRY_PENDING_TASKS){ |
84 | RETRY_PENDING_TASKS.add(this); | |
bf70dcc3 MG |
85 | } |
86 | } | |
87 | } |