X-Git-Url: http://wamblee.org/gitweb/?a=blobdiff_plain;f=support%2Fsrc%2Fmain%2Fjava%2Forg%2Fwamblee%2Fio%2FDirectoryMonitor.java;h=0f84183c1b4478cdb32aad51dcc49b4145eeebc8;hb=a327761c480f8f127e3663bc5886aca39d1a0682;hp=74723337f92af2744b2fd6dbfebf0d2b64785e2a;hpb=f7c3218ce2a75ce5ce287191d2ea54e850eb7559;p=utils

diff --git a/support/src/main/java/org/wamblee/io/DirectoryMonitor.java b/support/src/main/java/org/wamblee/io/DirectoryMonitor.java
index 74723337..0f84183c 100644
--- a/support/src/main/java/org/wamblee/io/DirectoryMonitor.java
+++ b/support/src/main/java/org/wamblee/io/DirectoryMonitor.java
@@ -12,7 +12,7 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- */ 
+ */
 
 package org.wamblee.io;
 
@@ -21,65 +21,90 @@ import java.io.FileFilter;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 /**
- * Monitors a directory for changes. 
- *
+ * Monitors a directory for changes.
+ * 
  * @author Erik Brakkee
  */
 public class DirectoryMonitor {
-    
-    private static final Log LOG = LogFactory.getLog(DirectoryMonitor.class);
-    
-    public static interface Listener { 
-        void fileChanged(File aFile); 
-        void fileCreated(File aFile); 
-        void fileDeleted(File aFile);
-    };
-    
-    private File _directory;
-    private FileFilter _filter; 
-    private Listener _listener;
-    private Map<File,Date> _contents; 
-    
-    public DirectoryMonitor(File aDirectory, FileFilter aFilefilter, Listener aListener) {
-        _directory = aDirectory;
-        if ( !_directory.isDirectory()) { 
-            throw new IllegalArgumentException("Directory '" + _directory + "' does not exist");
-        }
-        _filter = aFilefilter; 
-        _listener = aListener;
-        _contents = new HashMap<File,Date>();
-    }
-    
-    public void poll() {
-        LOG.debug("Polling " + _directory);
-        Map<File,Date> newContents = new HashMap<File,Date>();
-        File[] files = _directory.listFiles(_filter);
-        for (File file: files) { 
-            if ( _contents.containsKey(file)) { 
-                Date oldDate = _contents.get(file);
-                if (file.lastModified() != oldDate.getTime()) { 
-                    _listener.fileChanged(file);
-                } else { 
-                    // No change. 
-                }
-                _contents.remove(file);
-                newContents.put(file, new Date(file.lastModified()));
-            } else { 
-                _listener.fileCreated(file);
-                newContents.put(file, new Date(file.lastModified()));
-            }
-        }
-        for (File file: _contents.keySet()) { 
-            _listener.fileDeleted(file);
-        }
-        _contents = newContents;
-    }
+
+	private static final Log LOG = LogFactory.getLog(DirectoryMonitor.class);
+
+	public static interface Listener {
+		
+		void fileChanged(File aFile);
+
+		void fileCreated(File aFile);
+
+		void fileDeleted(File aFile);
+	};
+
+	private File _directory;
+	private FileFilter _filter;
+	private Listener _listener;
+	private Map<File, Date> _contents;
+
+	public DirectoryMonitor(File aDirectory, FileFilter aFilefilter,
+			Listener aListener) {
+		_directory = aDirectory;
+		if (!_directory.isDirectory()) {
+			throw new IllegalArgumentException("Directory '" + _directory
+					+ "' does not exist");
+		}
+		_filter = aFilefilter;
+		_listener = aListener;
+		_contents = new HashMap<File, Date>();
+	}
+
+	/**
+	 * Polls the directory for changes and notifies the listener of any changes. 
+	 * In case of any exceptions thrown by the listener while handling the changes, 
+	 * the next call to this method will invoked the listeners again for the same changes. 
+	 */
+	public void poll() {
+		LOG.debug("Polling " + _directory);
+		Map<File, Date> newContents = new HashMap<File, Date>();
+		File[] files = _directory.listFiles(_filter);
+
+		// Check deleted files. 
+		Set<File> deletedFiles = new HashSet<File>(_contents.keySet());
+		for (File file : files) {
+			if (file.isFile()) {
+				if (_contents.containsKey(file)) {
+					deletedFiles.remove(file);
+				}
+			}
+		}
+		for (File file : deletedFiles) {
+			_listener.fileDeleted(file);
+		}
+		
+		for (File file : files) {
+			if (file.isFile()) {
+				if (_contents.containsKey(file)) {
+					Date oldDate = _contents.get(file);
+					if (file.lastModified() != oldDate.getTime()) {
+						_listener.fileChanged(file);
+					} else {
+						// No change.
+					}
+					newContents.put(file, new Date(file.lastModified()));
+				} else {
+					_listener.fileCreated(file);
+					newContents.put(file, new Date(file.lastModified()));
+				}
+			}
+		}
+		
+		_contents = newContents;
+	}
 
 }