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| package photospace.vfs.event; |
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| import java.io.*; |
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| import java.util.*; |
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| import org.apache.commons.logging.*; |
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| |
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| public class FileSystemWatcher |
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| implements Runnable |
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| { |
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| private static final Log log = LogFactory.getLog(FileSystemWatcher.class); |
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| |
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| private Set roots = new HashSet(); |
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| private Set listeners = new HashSet(); |
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| private Map snapshot = new HashMap(); |
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| private FileFilter filter; |
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| private int sleep = 100; |
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| private Thread watcher; |
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| private boolean running = false; |
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| |
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1
| public void addListener(FileEventListener listener) throws IOException
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| { |
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1
| listeners.add(listener);
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| } |
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| |
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1
| public void addRoot(File file) throws IOException
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| { |
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0
| if (!file.exists()) throw new IllegalArgumentException(file + " does not exist");
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| roots.add(file.getCanonicalFile());
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| } |
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| |
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0
| public void setRoots(List roots) throws IOException
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| { |
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0
| this.roots = new HashSet();
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0
| for (Iterator i = roots.iterator(); i.hasNext();)
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| { |
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| addRoot((File) i.next());
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| } |
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| } |
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| |
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0
| public void setListeners(List listeners) throws IOException
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| { |
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0
| this.listeners = new HashSet();
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0
| for (Iterator i = listeners.iterator(); i.hasNext();)
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| { |
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0
| addListener((FileEventListener) i.next());
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| } |
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| } |
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| |
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1
| public void setFilter(FileFilter filter)
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| { |
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1
| this.filter = filter;
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| } |
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| |
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| public void start()
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| { |
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| log.info("Starting watching " + roots.size() + " filesystems: " + roots);
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| |
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1
| watcher = new Thread(this);
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1
| watcher.setPriority(Thread.MIN_PRIORITY);
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1
| running = true;
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1
| watcher.start();
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| } |
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| |
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0
| public void destroy()
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| { |
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0
| running = false;
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| } |
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| |
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1
| public void run()
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| { |
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1
| sleep(sleep);
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| |
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1
| snapshot = createSnapshot(new ArrayList(roots));
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| |
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50
| while (running)
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| { |
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50
| sleep(sleep);
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| |
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49
| try
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| { |
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| lookForChanges(new ArrayList(roots));
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| |
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| for (Iterator i = new ArrayList(snapshot.keySet()).iterator(); i.hasNext();)
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| { |
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85 |
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| File file = (File) i.next();
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86 |
85
| if (!file.exists())
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| { |
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1
| fireEvent(new FileEvent(FileEvent.DELETED, file));
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1
| snapshot.remove(file);
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| } |
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| } |
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| } |
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| catch (Exception e) |
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| { |
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0
| log.error("Exception watching filesystem. Sleeping for 30 seconds...", e);
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0
| sleep(30 * 1000);
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| } |
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| } |
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| } |
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| |
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51
| private synchronized void sleep(int milliseconds)
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| { |
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| |
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| try { wait(milliseconds); }
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| |
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| catch (InterruptedException e) { } |
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| } |
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1
| public Map createSnapshot(List roots)
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| { |
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1
| Map snapshot = new HashMap();
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1
| collect((File[]) roots.toArray(new File[] {}), snapshot);
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120 |
1
| return snapshot;
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| } |
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| |
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2
| private void collect(File[] from, Map to)
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| { |
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2
| for (int i = 0; i < from.length; i++)
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| { |
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1
| File file = from[i];
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128 |
1
| if (!to.containsKey(file))
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| { |
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1
| to.put(file, new Long(file.lastModified()));
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| } |
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| |
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1
| if (file.isDirectory()) collect(file.listFiles(filter), to);
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| } |
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| } |
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| |
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138 |
120
| private void lookForChanges(List files)
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| { |
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120
| for (Iterator i = files.iterator(); i.hasNext();)
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| { |
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142 |
84
| File file = (File) i.next();
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84
| if (!snapshot.containsKey(file))
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| { |
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2
| fireEvent(new FileEvent(FileEvent.CREATED, file));
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2
| snapshot.put(file, new Long(file.lastModified()));
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| } |
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148 |
82
| else if (file.lastModified() > ((Long) snapshot.get(file)).longValue())
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| { |
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150 |
4
| fireEvent(new FileEvent(FileEvent.UPDATED, file));
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151 |
4
| snapshot.put(file, new Long(file.lastModified()));
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| } |
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| |
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154 |
71
| if (file.isDirectory()) lookForChanges(Arrays.asList(file.listFiles(filter)));
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| } |
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| } |
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| |
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158 |
7
| private void fireEvent(FileEvent event)
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| { |
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160 |
7
| log.debug(event);
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| |
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162 |
7
| for (Iterator j = listeners.iterator(); j.hasNext();)
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| { |
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164 |
7
| FileEventListener listener = (FileEventListener) j.next();
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165 |
7
| try
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| { |
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167 |
7
| listener.handleFileEvent(event);
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| } |
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| catch (Throwable t) |
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| { |
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171 |
0
| log.error(listener + " threw an exception handling " + event, t);
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| } |
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173 |
| } |
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174 |
| } |
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175 |
| |
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176 |
1
| public void setSleep(int sleep)
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|
177 |
| { |
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178 |
1
| this.sleep = sleep;
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|
179 |
| } |
|
180 |
| |
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181 |
3
| public Map getSnapshot()
|
|
182 |
| { |
|
183 |
3
| return snapshot;
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184 |
| } |
|
185 |
| } |
