Index: src/test/org/apache/lucene/store/TestDirectory.java
===================================================================
--- src/test/org/apache/lucene/store/TestDirectory.java	(revision 713425)
+++ src/test/org/apache/lucene/store/TestDirectory.java	(working copy)
@@ -38,5 +38,36 @@
     } catch (AlreadyClosedException ace) {
     }
   }
+
+  public void testFSDirectory() throws Throwable {
+    String path = System.getProperty("tempDir");
+
+    Directory dir = FSDirectory.getDirectory(path);
+
+    // ensure that the same directory instance is returned, even though
+    // it's being opened from a different subclass
+    Directory dir2 = NIOFSDirectory.getDirectory(path);
+    assertTrue(dir == dir2);
+    dir2.close();
+
+    // ensure that the same directory instance is returned, even though
+    // it's being opened from a different subclass
+    dir2 = MMapDirectory.getDirectory(path);
+    assertTrue(dir == dir2);
+    dir2.close();
+
+    dir.close();
+    // after the original directory is closed, we should be able to
+    // get different subclass implementations
+    dir = NIOFSDirectory.getDirectory(path);
+    assertTrue(dir instanceof NIOFSDirectory);
+    dir.close();
+    
+    dir = MMapDirectory.getDirectory(path);
+    assertTrue(dir instanceof MMapDirectory);
+    dir.close();
+  }
+
+
 }
 
Index: src/java/org/apache/lucene/store/NIOFSDirectory.java
===================================================================
--- src/java/org/apache/lucene/store/NIOFSDirectory.java	(revision 713425)
+++ src/java/org/apache/lucene/store/NIOFSDirectory.java	(working copy)
@@ -43,6 +43,43 @@
 
 public class NIOFSDirectory extends FSDirectory {
 
+  /** Returns the directory instance for the named location.
+   * @param path the path to the directory.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(String path)
+      throws IOException {
+    return getDirectory(new File(path), null);
+  }
+
+  /** Returns the directory instance for the named location.
+   * @param path the path to the directory.
+   * @param lockFactory instance of {@link LockFactory} providing the
+   *        locking implementation.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(String path, LockFactory lockFactory)
+      throws IOException {
+    return getDirectory(new File(path), lockFactory);
+  }
+
+  /** Returns the directory instance for the named location.
+   * @param file the path to the directory.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(File file)
+    throws IOException {
+    return getDirectory(file, null);
+  }
+
+  /** Returns the directory instance for the named location.
+   * @param file the path to the directory.
+   * @param lockFactory instance of {@link LockFactory} providing the
+   *        locking implementation.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(File file, LockFactory lockFactory)
+    throws IOException
+  {
+    return getDirectory(NIOFSDirectory.class, file, lockFactory);
+  }
+
   // Inherit javadoc
   public IndexInput openInput(String name, int bufferSize) throws IOException {
     ensureOpen();
Index: src/java/org/apache/lucene/store/MMapDirectory.java
===================================================================
--- src/java/org/apache/lucene/store/MMapDirectory.java	(revision 713425)
+++ src/java/org/apache/lucene/store/MMapDirectory.java	(working copy)
@@ -33,6 +33,44 @@
  */
 public class MMapDirectory extends FSDirectory {
 
+  /** Returns the directory instance for the named location.
+   * @param path the path to the directory.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(String path)
+      throws IOException {
+    return getDirectory(new File(path), null);
+  }
+
+  /** Returns the directory instance for the named location.
+   * @param path the path to the directory.
+   * @param lockFactory instance of {@link LockFactory} providing the
+   *        locking implementation.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(String path, LockFactory lockFactory)
+      throws IOException {
+    return getDirectory(new File(path), lockFactory);
+  }
+
+  /** Returns the directory instance for the named location.
+   * @param file the path to the directory.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(File file)
+    throws IOException {
+    return getDirectory(file, null);
+  }
+
+  /** Returns the directory instance for the named location.
+   * @param file the path to the directory.
+   * @param lockFactory instance of {@link LockFactory} providing the
+   *        locking implementation.
+   * @return the FSDirectory for the named file.  */
+  public static FSDirectory getDirectory(File file, LockFactory lockFactory)
+    throws IOException
+  {
+    return getDirectory(MMapDirectory.class, file, lockFactory);
+  }
+
+
   private static class MMapIndexInput extends IndexInput {
 
     private ByteBuffer buffer;
Index: src/java/org/apache/lucene/store/FSDirectory.java
===================================================================
--- src/java/org/apache/lucene/store/FSDirectory.java	(revision 713425)
+++ src/java/org/apache/lucene/store/FSDirectory.java	(working copy)
@@ -157,7 +157,8 @@
     return getDirectory(file, null);
   }
 
-  /** Returns the directory instance for the named location.
+
+    /** Returns the directory instance for the named location.
    * @param file the path to the directory.
    * @param lockFactory instance of {@link LockFactory} providing the
    *        locking implementation.
@@ -165,6 +166,18 @@
   public static FSDirectory getDirectory(File file, LockFactory lockFactory)
     throws IOException
   {
+    return getDirectory(IMPL, file, lockFactory);
+  }
+
+  /** Returns the directory instance for the named location, using directoryImpl
+   * to create a new FSDirectory class or subclass if one does not already exist.
+   * @param file the path to the directory.
+   * @param lockFactory instance of {@link LockFactory} providing the
+   *        locking implementation.
+   * @return the FSDirectory for the named file.  */
+  protected static FSDirectory getDirectory(Class directoryImpl, File file, LockFactory lockFactory)
+    throws IOException
+  {
     file = new File(file.getCanonicalPath());
 
     if (file.exists() && !file.isDirectory())
@@ -179,7 +192,7 @@
       dir = (FSDirectory)DIRECTORIES.get(file);
       if (dir == null) {
         try {
-          dir = (FSDirectory)IMPL.newInstance();
+          dir = (FSDirectory)directoryImpl.newInstance();
         } catch (Exception e) {
           throw new RuntimeException("cannot load FSDirectory class: " + e.toString(), e);
         }