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