Index: FSDirectory.java
===================================================================
RCS file: /home/cvspublic/jakarta-lucene/src/java/org/apache/lucene/store/FSDirectory.java,v
retrieving revision 1.36
diff -u -r1.36 FSDirectory.java
--- FSDirectory.java	28 Sep 2004 20:45:26 -0000	1.36
+++ FSDirectory.java	16 Oct 2004 19:42:34 -0000
@@ -16,11 +16,13 @@
  * limitations under the License.
  */
 
+import java.io.FileFilter;
 import java.io.IOException;
 import java.io.File;
 import java.io.RandomAccessFile;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
+import java.util.ArrayList;
 import java.util.Hashtable;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -36,6 +38,7 @@
  * @author Doug Cutting
  */
 public class FSDirectory extends Directory {
+  
   /** This cache of directories ensures that there is a unique Directory
    * instance per path, so that synchronization on the Directory can be used to
    * synchronize access between readers and writers.
@@ -79,6 +82,50 @@
     }
   }
 
+  /** FileFilter for filenames known to lucene */
+  private final FileFilter filter = new FileFilter() {
+    public boolean accept(File file) {
+        final String name = file.getName();
+        if (name.equals("segments"))
+          return true;
+        else if (name.equals("deletable"))
+          return true;
+        else if (name.endsWith("cfs"))
+          return true;
+        else if (name.endsWith("fnm"))
+          return true;
+        else if (name.endsWith(".fdx"))
+          return true;
+        else if (name.endsWith(".fdt"))
+          return true;
+        else if (name.endsWith(".tis"))
+          return true;
+        else if (name.endsWith(".tii"))
+          return true;
+        else if (name.endsWith(".frq"))
+          return true;
+        else if (name.endsWith(".prx"))
+          return true;
+        else if (name.endsWith(".tvx"))
+          return true;
+        else if (name.endsWith(".tvd"))
+          return true;
+        else if (name.endsWith(".tvf"))
+          return true;
+        else if (name.endsWith(".del"))
+          return true;
+        
+        /**
+         * possible norms file
+         * this could be made better when switching to Java 1.4 level code using a regexp
+         */
+        else if (name.indexOf(".f") > 0)
+          return true;
+        else
+          return false;
+    }
+  };
+  
   /** A buffer optionally used in renameTo method */
   private byte[] buffer = null;
 
@@ -157,7 +204,8 @@
       if (!directory.mkdirs())
         throw new IOException("Cannot create directory: " + directory);
 
-    String[] files = directory.list();            // clear old files
+    // use list(filter) to delete only files belonging to lucene
+    String[] files = list(filter);            // clear old files
     for (int i = 0; i < files.length; i++) {
       File file = new File(directory, files[i]);
       if (!file.delete())
@@ -180,6 +228,21 @@
     return directory.list();
   }
 
+  /** Returns an array of strings for filenames belonging to lucene */
+  private String[] list(FileFilter filter) {
+    String names[] = list();
+    if ((names == null) || (filter == null)) {
+      return names;
+    }
+    ArrayList v = new ArrayList();
+    for (int i = 0 ; i < names.length ; i++) {
+      if (filter.accept(new File(directory, names[i]))) {
+        v.add(names[i]);
+      }
+    }
+    return (String[])(v.toArray(new String[0]));
+  }
+  
   /** Returns true iff a file with the given name exists. */
   public boolean fileExists(String name) {
     File file = new File(directory, name);