Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
FileMonitor |
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| 0.0;0 | ||||
FileMonitor$FileMonitorNotifier |
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| 0.0;0 |
1 | /* | |
2 | * $Id: FileMonitor.java 19191 2010-08-25 21:05:23Z tcarlson $ | |
3 | * -------------------------------------------------------------------------------------- | |
4 | * Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com | |
5 | * | |
6 | * The software in this package is published under the terms of the CPAL v1.0 | |
7 | * license, a copy of which has been included with this distribution in the | |
8 | * LICENSE.txt file. | |
9 | */ | |
10 | ||
11 | package org.mule.util.monitor; | |
12 | ||
13 | import java.beans.ExceptionListener; | |
14 | import java.io.File; | |
15 | import java.io.IOException; | |
16 | import java.lang.ref.WeakReference; | |
17 | import java.util.ArrayList; | |
18 | import java.util.Collection; | |
19 | import java.util.HashMap; | |
20 | import java.util.Iterator; | |
21 | import java.util.List; | |
22 | import java.util.Map; | |
23 | import java.util.Timer; | |
24 | import java.util.TimerTask; | |
25 | ||
26 | /** | |
27 | * Class for monitoring changes in disk files. Usage: 1. Implement the FileListener | |
28 | * interface. 2. Create a FileMonitor instance. 3. Add the file(s)/directory(ies) to | |
29 | * listen for. fileChanged() will be called when a monitored file is created, deleted | |
30 | * or its modified time changes. | |
31 | */ | |
32 | 0 | public class FileMonitor |
33 | { | |
34 | private Timer timer; | |
35 | private Map<File, Long> files; | |
36 | private List<WeakReference<FileListener>> listeners; | |
37 | private long pollingInterval; | |
38 | ||
39 | /** | |
40 | * Create a file monitor instance with specified polling interval. | |
41 | * | |
42 | * @param pollingInterval Polling interval in milli seconds. | |
43 | */ | |
44 | public FileMonitor(long pollingInterval) | |
45 | 0 | { |
46 | 0 | files = new HashMap<File, Long>(); |
47 | 0 | listeners = new ArrayList<WeakReference<FileListener>>(); |
48 | 0 | timer = new Timer(true); |
49 | 0 | this.pollingInterval = pollingInterval; |
50 | 0 | } |
51 | ||
52 | /** | |
53 | * Stop the file monitor polling. | |
54 | */ | |
55 | public void stop() | |
56 | { | |
57 | 0 | timer.cancel(); |
58 | 0 | } |
59 | ||
60 | public void start() | |
61 | { | |
62 | 0 | timer.schedule(new FileMonitorNotifier(), 0, pollingInterval); |
63 | 0 | } |
64 | ||
65 | /** | |
66 | * Add file to listen for. File may be any java.io.File (including a directory) | |
67 | * and may well be a non-existing file in the case where the creating of the file | |
68 | * is to be trepped. <p/> More than one file can be listened for. When the | |
69 | * specified file is created, modified or deleted, listeners are notified. | |
70 | * | |
71 | * @param file File to listen for. | |
72 | */ | |
73 | public void addFile(File file) | |
74 | { | |
75 | 0 | if (!files.containsKey(file)) |
76 | { | |
77 | 0 | long modifiedTime = file.exists() ? file.lastModified() : -1; |
78 | 0 | files.put(file, new Long(modifiedTime)); |
79 | } | |
80 | 0 | } |
81 | ||
82 | /** | |
83 | * Remove specified file for listening. | |
84 | * | |
85 | * @param file File to remove. | |
86 | */ | |
87 | public void removeFile(File file) | |
88 | { | |
89 | 0 | files.remove(file); |
90 | 0 | } |
91 | ||
92 | /** | |
93 | * Add listener to this file monitor. | |
94 | * | |
95 | * @param fileListener Listener to add. | |
96 | */ | |
97 | public void addListener(FileListener fileListener) | |
98 | { | |
99 | // Don't add if its already there | |
100 | 0 | for (WeakReference<FileListener> reference : listeners) |
101 | { | |
102 | 0 | FileListener listener = reference.get(); |
103 | 0 | if (listener == fileListener) |
104 | { | |
105 | 0 | return; |
106 | } | |
107 | 0 | } |
108 | ||
109 | // Use WeakReference to avoid memory leak if this becomes the | |
110 | // sole reference to the object. | |
111 | 0 | listeners.add(new WeakReference<FileListener>(fileListener)); |
112 | 0 | } |
113 | ||
114 | /** | |
115 | * Remove listener from this file monitor. | |
116 | * | |
117 | * @param fileListener Listener to remove. | |
118 | */ | |
119 | public void removeListener(FileListener fileListener) | |
120 | { | |
121 | 0 | for (Iterator<WeakReference<FileListener>> i = listeners.iterator(); i.hasNext();) |
122 | { | |
123 | 0 | WeakReference<FileListener> reference = i.next(); |
124 | 0 | FileListener listener = reference.get(); |
125 | 0 | if (listener == fileListener) |
126 | { | |
127 | 0 | i.remove(); |
128 | 0 | break; |
129 | } | |
130 | 0 | } |
131 | 0 | } |
132 | ||
133 | /** | |
134 | * This is the timer thread which is executed every n milliseconds according to | |
135 | * the setting of the file monitor. | |
136 | */ | |
137 | public class FileMonitorNotifier extends TimerTask | |
138 | { | |
139 | private ExceptionListener exceptionListener; | |
140 | ||
141 | public FileMonitorNotifier() | |
142 | 0 | { |
143 | 0 | super(); |
144 | 0 | } |
145 | ||
146 | public FileMonitorNotifier(ExceptionListener exceptionListener) | |
147 | 0 | { |
148 | 0 | this.exceptionListener = exceptionListener; |
149 | 0 | } |
150 | ||
151 | public void run() | |
152 | { | |
153 | // Loop over the registered files and see which have changed. | |
154 | // Use a copy of the list in case listener wants to alter the | |
155 | // list within its fileChanged method. | |
156 | 0 | Collection<File> fileKeys = new ArrayList<File>(files.keySet()); |
157 | ||
158 | 0 | for (File file : fileKeys) |
159 | { | |
160 | 0 | long lastModifiedTime = files.get(file).longValue(); |
161 | 0 | long newModifiedTime = file.exists() ? file.lastModified() : -1; |
162 | ||
163 | // Chek if file has changed | |
164 | 0 | if (newModifiedTime != lastModifiedTime) |
165 | { | |
166 | // Register new modified time | |
167 | 0 | files.put(file, new Long(newModifiedTime)); |
168 | ||
169 | // Notify listeners | |
170 | 0 | for (Iterator<WeakReference<FileListener>> j = listeners.iterator(); j.hasNext();) |
171 | { | |
172 | 0 | WeakReference<FileListener> reference = j.next(); |
173 | 0 | FileListener listener = reference.get(); |
174 | ||
175 | // Remove from list if the back-end object has been GC'd | |
176 | 0 | if (listener == null) |
177 | { | |
178 | 0 | j.remove(); |
179 | } | |
180 | else | |
181 | { | |
182 | try | |
183 | { | |
184 | 0 | listener.fileChanged(file); |
185 | } | |
186 | 0 | catch (IOException e) |
187 | { | |
188 | // TODO MULE-863: What should we do if null? | |
189 | 0 | if (exceptionListener != null) |
190 | { | |
191 | 0 | exceptionListener.exceptionThrown(e); |
192 | } | |
193 | 0 | } |
194 | } | |
195 | 0 | } |
196 | } | |
197 | 0 | } |
198 | 0 | } |
199 | } | |
200 | } |