# HG changeset patch
# User Earwin Burrfoot <earwin@gmail.com>
# Date 1269243135 -10800
# Node ID 7fc8fc1c9082d098bece0279ab377c3e59350600
# Parent  9e755a9782abbb4b6b9350d2c96916b6b5b94447
[mq]: LUCENE-2339

diff --git a/src/java/org/apache/lucene/store/Directory.java b/src/java/org/apache/lucene/store/Directory.java
--- a/src/java/org/apache/lucene/store/Directory.java
+++ b/src/java/org/apache/lucene/store/Directory.java
@@ -20,6 +20,10 @@
 import java.io.IOException;
 import java.io.Closeable;
 
+import java.util.ArrayList;
+import static java.util.Arrays.asList;
+import java.util.Iterator;
+import java.util.List;
 import org.apache.lucene.index.IndexFileNameFilter;
 
 /** A Directory is a flat list of files.  Files may be written once, when they
@@ -159,42 +163,56 @@
   }
 
   /**
-   * Copy contents of a directory src to a directory dest.
-   * If a file in src already exists in dest then the
-   * one in dest will be blindly overwritten.
+   * Copy contents of a directory src to a directory dest. If a file in src already exists in dest then the one in dest
+   * will be blindly overwritten.
+   * <p/>
+   * <p><b>NOTE:</b> the source directory cannot change while this method is running.  Otherwise the results are
+   * undefined and you could easily hit a FileNotFoundException.
+   * <p/>
+   * <p><b>NOTE:</b> this method only copies files that look like index files (ie, have extensions matching the known
+   * extensions of index files).
    *
-   * <p><b>NOTE:</b> the source directory cannot change
-   * while this method is running.  Otherwise the results
-   * are undefined and you could easily hit a
-   * FileNotFoundException.
-   *
-   * <p><b>NOTE:</b> this method only copies files that look
-   * like index files (ie, have extensions matching the
-   * known extensions of index files).
-   *
-   * @param src source directory
-   * @param dest destination directory
+   * @param src         source directory
+   * @param dest        destination directory
    * @param closeDirSrc if <code>true</code>, call {@link #close()} method on source directory
-   * @throws IOException
    */
   public static void copy(Directory src, Directory dest, boolean closeDirSrc) throws IOException {
-    final String[] files = src.listAll();
+    List<String> filenames = new ArrayList<String>(asList(src.listAll()));
 
     IndexFileNameFilter filter = IndexFileNameFilter.getFilter();
 
+    for (Iterator<String> iterator = filenames.iterator(); iterator.hasNext();)
+      if (!filter.accept(null, iterator.next()))
+        iterator.remove();
+
+    copy(src, dest, filenames);
+
+    if (closeDirSrc)
+      src.close();
+  }
+
+  /**
+   * Copy given files of a directory src to a directory dest. If a file in src already exists in dest then the one in
+   * dest will be blindly overwritten.
+   * <p/>
+   * <p><b>NOTE:</b> the source directory cannot change while this method is running.  Otherwise the results are
+   * undefined and you could easily hit a FileNotFoundException. </p>
+   *
+   * @param src       source directory
+   * @param dest      destination directory
+   * @param filenames file names to be copied
+   */
+  public static void copy(Directory src, Directory dest, Iterable<String> filenames) throws IOException {
     byte[] buf = new byte[BufferedIndexOutput.BUFFER_SIZE];
-    for (int i = 0; i < files.length; i++) {
-
-      if (!filter.accept(null, files[i]))
-        continue;
+    for (String filename : filenames) {
 
       IndexOutput os = null;
       IndexInput is = null;
       try {
         // create file in dest directory
-        os = dest.createOutput(files[i]);
+        os = dest.createOutput(filename);
         // read current file
-        is = src.openInput(files[i]);
+        is = src.openInput(filename);
         // and copy to dest directory
         long len = is.length();
         long readCount = 0;
@@ -215,8 +233,6 @@
         }
       }
     }
-    if(closeDirSrc)
-      src.close();
   }
 
   /**