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| package photospace.vfs.event; |
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| |
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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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| public void addListener(FileEventListener listener) throws IOException
|
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| { |
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| listeners.add(listener);
|
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| } |
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| |
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| public void addRoot(File file) throws IOException
|
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| { |
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| 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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| public void setRoots(List roots) throws IOException
|
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| { |
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| this.roots = new HashSet();
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| 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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| this.listeners = new HashSet();
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| for (Iterator i = listeners.iterator(); i.hasNext();)
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| { |
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| addListener((FileEventListener) i.next());
|
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| } |
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| } |
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| |
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| public void setFilter(FileFilter filter)
|
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| { |
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| 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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| watcher = new Thread(this);
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| watcher.setPriority(Thread.MIN_PRIORITY);
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| running = true;
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| 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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| running = false;
|
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| } |
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| |
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| public void run()
|
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| { |
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| sleep(sleep);
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| |
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| snapshot = createSnapshot(new ArrayList(roots));
|
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| |
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| while (running)
|
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| { |
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| sleep(sleep);
|
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| |
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| 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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| File file = (File) i.next();
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| if (!file.exists())
|
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| { |
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| fireEvent(new FileEvent(FileEvent.DELETED, file));
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| 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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| log.error("Exception watching filesystem. Sleeping for 30 seconds...", e);
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| sleep(30 * 1000);
|
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| } |
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| } |
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| } |
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| |
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| 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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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| public Map createSnapshot(List roots)
|
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| { |
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| Map snapshot = new HashMap();
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| collect((File[]) roots.toArray(new File[] {}), snapshot);
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| 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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| for (int i = 0; i < from.length; i++)
|
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| { |
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| File file = from[i];
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| if (!to.containsKey(file))
|
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| { |
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| to.put(file, new Long(file.lastModified()));
|
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| } |
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| |
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| if (file.isDirectory()) collect(file.listFiles(filter), to);
|
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| } |
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| } |
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| |
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| |
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| private void lookForChanges(List files)
|
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| { |
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| for (Iterator i = files.iterator(); i.hasNext();)
|
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| { |
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| File file = (File) i.next();
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| if (!snapshot.containsKey(file))
|
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| { |
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| fireEvent(new FileEvent(FileEvent.CREATED, file));
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| snapshot.put(file, new Long(file.lastModified()));
|
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| } |
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| else if (file.lastModified() > ((Long) snapshot.get(file)).longValue())
|
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| { |
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| fireEvent(new FileEvent(FileEvent.UPDATED, file));
|
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4
| snapshot.put(file, new Long(file.lastModified()));
|
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| } |
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| |
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| 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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| private void fireEvent(FileEvent event)
|
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| { |
160 |
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| log.debug(event);
|
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| |
162 |
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| for (Iterator j = listeners.iterator(); j.hasNext();)
|
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| { |
164 |
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| FileEventListener listener = (FileEventListener) j.next();
|
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| try
|
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| { |
167 |
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| listener.handleFileEvent(event);
|
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| } |
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| catch (Throwable t) |
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| { |
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| log.error(listener + " threw an exception handling " + event, t);
|
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| } |
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| } |
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| } |
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| |
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1
| public void setSleep(int sleep)
|
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| { |
178 |
1
| this.sleep = sleep;
|
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| } |
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| |
181 |
3
| public Map getSnapshot()
|
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| { |
183 |
3
| return snapshot;
|
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| } |
185 |
| } |