340949 Scanner delays file notifications until files are stable

git-svn-id: svn+ssh://dev.eclipse.org/svnroot/rt/org.eclipse.jetty/jetty/trunk@2948 7e9141cc-0065-0410-87d8-b60c137991c4

6 files changed, 135 insertions, 42 deletions

diff --git a/VERSION.txt b/VERSION.txt
index bde2b54903..e6629b0fc7 100644
--- a/VERSION.txt
+++ b/VERSION.txt
@@ -10,6 +10,7 @@ jetty-7.3.2-SNAPSHOT
  + 340838 Update ConnectHandler to perform half closes properly
  + 340878 Integrations should be able to load their own keystores
  + 340920 Dynamically assign RMI registry port for integration testing
+ + 340949 Scanner delays file notifications until files are stable
  + 341006 Move inner enums out into separate file
  + 341105 Stack trace is printed for an ignored exception
  + 341145 WebAppContext MBean attribute serverClasses returns empty value
diff --git a/jetty-client/src/test/java/org/eclipse/jetty/client/ExpireTest.java b/jetty-client/src/test/java/org/eclipse/jetty/client/ExpireTest.java
index fee9e6fe88..0b645d6fd5 100644
--- a/jetty-client/src/test/java/org/eclipse/jetty/client/ExpireTest.java
+++ b/jetty-client/src/test/java/org/eclipse/jetty/client/ExpireTest.java
@@ -16,6 +16,7 @@ package org.eclipse.jetty.client;
 import static org.junit.Assert.assertTrue;
 
 import java.io.IOException;
+import java.io.InterruptedIOException;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
@@ -60,7 +61,6 @@ public class ExpireTest
                 }
                 catch (InterruptedException x)
                 {
-                    throw new ServletException(x);
                 }
             }
         });
diff --git a/jetty-deploy/src/test/java/org/eclipse/jetty/deploy/providers/WebAppProviderTest.java b/jetty-deploy/src/test/java/org/eclipse/jetty/deploy/providers/WebAppProviderTest.java
index 0f2e562f15..8e6357bd43 100644
--- a/jetty-deploy/src/test/java/org/eclipse/jetty/deploy/providers/WebAppProviderTest.java
+++ b/jetty-deploy/src/test/java/org/eclipse/jetty/deploy/providers/WebAppProviderTest.java
@@ -13,8 +13,8 @@ import org.junit.Test;
 
 public class WebAppProviderTest
 {
-	@Rule
-	public TestingDir testdir = new TestingDir();
+    @Rule
+    public TestingDir testdir = new TestingDir();
     private static XmlConfiguredJetty jetty;
 
     @Before
diff --git a/jetty-policy/src/main/java/org/eclipse/jetty/policy/PolicyMonitor.java b/jetty-policy/src/main/java/org/eclipse/jetty/policy/PolicyMonitor.java
index 93cf4b7182..64a1755fec 100644
--- a/jetty-policy/src/main/java/org/eclipse/jetty/policy/PolicyMonitor.java
+++ b/jetty-policy/src/main/java/org/eclipse/jetty/policy/PolicyMonitor.java
@@ -40,7 +40,7 @@ public abstract class PolicyMonitor extends AbstractLifeCycle
     /**
      * scan interval in seconds for policy file changes
      */
-    private int _scanInterval = 10;
+    private int _scanInterval = 1;
             
     /**
      * specialized listener enabling waitForScan() functionality
@@ -72,6 +72,7 @@ public abstract class PolicyMonitor extends AbstractLifeCycle
      */
     public PolicyMonitor( String directory )
     {
+        this();
         _policyDirectory = directory;
     }
     
@@ -144,7 +145,8 @@ public abstract class PolicyMonitor extends AbstractLifeCycle
      */
     public synchronized void waitForScan() throws Exception
     {
-        CountDownLatch latch = new CountDownLatch(1);
+        // wait for 2 scans for stable files
+        CountDownLatch latch = new CountDownLatch(2);
         
        _scanningListener.setScanningLatch(latch);
        _scanner.scan();
diff --git a/jetty-policy/src/test/java/org/eclipse/jetty/policy/PolicyMonitorTest.java b/jetty-policy/src/test/java/org/eclipse/jetty/policy/PolicyMonitorTest.java
index 0c16fe5c65..8174d61c06 100644
--- a/jetty-policy/src/test/java/org/eclipse/jetty/policy/PolicyMonitorTest.java
+++ b/jetty-policy/src/test/java/org/eclipse/jetty/policy/PolicyMonitorTest.java
@@ -36,6 +36,7 @@ public class PolicyMonitorTest
                 count.incrementAndGet();
             }
         };
+        monitor.setScanInterval(1);
         
         monitor.start();
         
diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java b/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java
index 9456299f4e..08e030815b 100644
--- a/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java
@@ -29,6 +29,7 @@ import java.util.Set;
 import java.util.Timer;
 import java.util.TimerTask;
 
+import org.eclipse.jetty.util.component.AbstractLifeCycle;
 import org.eclipse.jetty.util.log.Log;
 
 
@@ -38,16 +39,15 @@ import org.eclipse.jetty.util.log.Log;
  * Utility for scanning a directory for added, removed and changed
  * files and reporting these events via registered Listeners.
  *
- * TODO AbstractLifeCycle
  */
-public class Scanner
+public class Scanner extends AbstractLifeCycle
 {
     private static int __scannerId=0;
     private int _scanInterval;
     private int _scanCount = 0;
     private final List<Listener> _listeners = new ArrayList<Listener>();
-    private final Map<String,Long> _prevScan = new HashMap<String,Long> ();
-    private final Map<String,Long> _currentScan = new HashMap<String,Long> ();
+    private final Map<String,TimeNSize> _prevScan = new HashMap<String,TimeNSize> ();
+    private final Map<String,TimeNSize> _currentScan = new HashMap<String,TimeNSize> ();
     private FilenameFilter _filter;
     private final List<File> _scanDirs = new ArrayList<File>();
     private volatile boolean _running = false;
@@ -56,8 +56,45 @@ public class Scanner
     private Timer _timer;
     private TimerTask _task;
     private int _scanDepth=0;
+    
+    public enum Notification { ADDED, CHANGED, REMOVED };
+    private final Map<String,Notification> _notifications = new HashMap<String,Notification>();
 
-
+    static class TimeNSize
+    {
+        final long _lastModified;
+        final long _size;
+        
+        public TimeNSize(long lastModified, long size)
+        {
+            _lastModified = lastModified;
+            _size = size;
+        }
+        
+        @Override
+        public int hashCode()
+        {
+            return (int)_lastModified^(int)_size;
+        }
+        
+        @Override
+        public boolean equals(Object o)
+        {
+            if (o instanceof TimeNSize)
+            {
+                TimeNSize tns = (TimeNSize)o;
+                return tns._lastModified==_lastModified && tns._size==_size;
+            }
+            return false;
+        }
+        
+        @Override
+        public String toString()
+        {
+            return "[lm="+_lastModified+",s="+_size+"]";
+        }
+    }
+    
     /**
      * Listener
      * 
@@ -274,7 +311,7 @@ public class Scanner
     /**
      * Start the scanning action.
      */
-    public synchronized void start ()
+    public synchronized void doStart()
     {
         if (_running)
             return;
@@ -285,6 +322,7 @@ public class Scanner
         {
             // if files exist at startup, report them
             scan();
+            scan(); // scan twice so files reported as stable
         }
         else
         {
@@ -321,14 +359,14 @@ public class Scanner
             {
                 _timer = newTimer();
                 _task = newTimerTask();
-                _timer.schedule(_task, 1000L*getScanInterval(),1000L*getScanInterval());
+                _timer.schedule(_task, 1010L*getScanInterval(),1010L*getScanInterval());
             }
         }
     }
     /**
      * Stop the scanning.
      */
-    public synchronized void stop ()
+    public synchronized void doStop()
     {
         if (_running)
         {
@@ -388,45 +426,97 @@ public class Scanner
      * @param currentScan the info from the most recent pass
      * @param oldScan info from the previous pass
      */
-    public void reportDifferences (Map<String,Long> currentScan, Map<String,Long> oldScan) 
+    public synchronized void reportDifferences (Map<String,TimeNSize> currentScan, Map<String,TimeNSize> oldScan) 
     {
-        List<String> bulkChanges = new ArrayList<String>();
-        
+        // scan the differences and add what was found to the map of notifications:
+
         Set<String> oldScanKeys = new HashSet<String>(oldScan.keySet());
-        Iterator<Entry<String, Long>> itor = currentScan.entrySet().iterator();
-        while (itor.hasNext())
+        
+        // Look for new and changed files
+        for (Map.Entry<String, TimeNSize> entry: currentScan.entrySet())
         {
-            Map.Entry<String, Long> entry = itor.next();
-            if (!oldScanKeys.contains(entry.getKey()))
+            String file = entry.getKey(); 
+            if (!oldScanKeys.contains(file))
             {
-                Log.debug("File added: "+entry.getKey());
-                reportAddition ((String)entry.getKey());
-                bulkChanges.add(entry.getKey());
+                Notification old=_notifications.put(file,Notification.ADDED);
+                if (old!=null)
+                { 
+                    switch(old)
+                    {
+                        case REMOVED: 
+                        case CHANGED:
+                            _notifications.put(file,Notification.CHANGED);
+                    }
+                }
             }
-            else if (!oldScan.get(entry.getKey()).equals(entry.getValue()))
+            else if (!oldScan.get(file).equals(currentScan.get(file)))
             {
-                Log.debug("File changed: "+entry.getKey());
-                reportChange((String)entry.getKey());
-                oldScanKeys.remove(entry.getKey());
-                bulkChanges.add(entry.getKey());
+                Notification old=_notifications.put(file,Notification.CHANGED);
+                if (old!=null)
+                {
+                    switch(old)
+                    {
+                        case ADDED:
+                            _notifications.put(file,Notification.ADDED);
+                    }
+                }
             }
-            else
-                oldScanKeys.remove(entry.getKey());
         }
-
-        if (!oldScanKeys.isEmpty())
+        
+        // Look for deleted files
+        for (String file : oldScan.keySet())
         {
-
-            Iterator<String> keyItor = oldScanKeys.iterator();
-            while (keyItor.hasNext())
+            if (!currentScan.containsKey(file))
             {
-                String filename = (String)keyItor.next();
-                Log.debug("File removed: "+filename);
-                reportRemoval(filename);
-                bulkChanges.add(filename);
+                Notification old=_notifications.put(file,Notification.REMOVED);
+                if (old!=null)
+                {
+                    switch(old)
+                    {
+                        case ADDED:
+                            _notifications.remove(file);
+                    }
+                }
             }
         }
         
+        if (Log.isDebugEnabled())
+            Log.debug("scanned "+_notifications);
+                
+        // Process notifications
+        // Only process notifications that are for stable files (ie same in old and current scan).
+        List<String> bulkChanges = new ArrayList<String>();
+        for (Iterator<Entry<String,Notification>> iter = _notifications.entrySet().iterator();iter.hasNext();)
+        {
+            Entry<String,Notification> entry=iter.next();
+            String file=entry.getKey();
+            
+            // Is the file stable?
+            if (oldScan.containsKey(file))
+            {
+                if (!oldScan.get(file).equals(currentScan.get(file)))
+                    continue;
+            }
+            else if (currentScan.containsKey(file))
+                continue;
+                            
+            // File is stable so notify
+            Notification notification=entry.getValue();
+            iter.remove();
+            bulkChanges.add(file);
+            switch(notification)
+            {
+                case ADDED:
+                    reportAddition(file);
+                    break;
+                case CHANGED:
+                    reportChange(file);
+                    break;
+                case REMOVED:
+                    reportRemoval(file);
+                    break;
+            }
+        }
         if (!bulkChanges.isEmpty())
             reportBulkChanges(bulkChanges);
     }
@@ -438,7 +528,7 @@ public class Scanner
      * @param f file or directory
      * @param scanInfoMap map of filenames to last modified times
      */
-    private void scanFile (File f, Map<String,Long> scanInfoMap, int depth)
+    private void scanFile (File f, Map<String,TimeNSize> scanInfoMap, int depth)
     {
         try
         {
@@ -450,8 +540,7 @@ public class Scanner
                 if ((_filter == null) || ((_filter != null) && _filter.accept(f.getParentFile(), f.getName())))
                 {
                     String name = f.getCanonicalPath();
-                    long lastModified = f.lastModified();
-                    scanInfoMap.put(name, new Long(lastModified));
+                    scanInfoMap.put(name, new TimeNSize(f.lastModified(),f.length()));
                 }
             }