Index: CHANGES.txt
===================================================================
--- CHANGES.txt	(revision 658890)
+++ CHANGES.txt	(working copy)
@@ -64,6 +64,11 @@
     replacement character U+FFFD.  This is a change to the index file
     format.  (Marvin Humphrey via Mike McCandless)
 
+ 8. LUCENE-1288: Add getVersion() and getGeneration() to IndexCommit.
+    getVersion() returns the same value that IndexReader.getVersion()
+    returns when the reader is opened on the same commit.  (Jason
+    Rutherglen via Mike McCandless)
+
 Bug fixes
     
  1. LUCENE-1134: Fixed BooleanQuery.rewrite to only optimize a single 
Index: src/test/org/apache/lucene/index/TestDeletionPolicy.java
===================================================================
--- src/test/org/apache/lucene/index/TestDeletionPolicy.java	(revision 658890)
+++ src/test/org/apache/lucene/index/TestDeletionPolicy.java	(working copy)
@@ -43,10 +43,17 @@
 public class TestDeletionPolicy extends LuceneTestCase
 {
   private void verifyCommitOrder(List commits) {
-    long last = SegmentInfos.generationFromSegmentsFileName(((IndexCommit) commits.get(0)).getSegmentsFileName());
+    final IndexCommit firstCommit = ((IndexCommit) commits.get(0));
+    long last = SegmentInfos.generationFromSegmentsFileName(firstCommit.getSegmentsFileName());
+    assertEquals(last, firstCommit.getGeneration());
+    long lastVersion = firstCommit.getVersion();
     for(int i=1;i<commits.size();i++) {
-      long now = SegmentInfos.generationFromSegmentsFileName(((IndexCommit) commits.get(i)).getSegmentsFileName());
+      final IndexCommit commit = ((IndexCommit) commits.get(i));
+      long now = SegmentInfos.generationFromSegmentsFileName(commit.getSegmentsFileName());
+      long nowVersion = commit.getVersion();
       assertTrue("SegmentInfos commits are out-of-order", now > last);
+      assertTrue("SegmentInfos versions are out-of-order", nowVersion > lastVersion);
+      assertEquals(now, commit.getGeneration());
       last = now;
     }
   }
Index: src/java/org/apache/lucene/index/DirectoryIndexReader.java
===================================================================
--- src/java/org/apache/lucene/index/DirectoryIndexReader.java	(revision 658890)
+++ src/java/org/apache/lucene/index/DirectoryIndexReader.java	(working copy)
@@ -343,6 +343,8 @@
     private String segmentsFileName;
     Collection files;
     Directory dir;
+    long generation;
+    long version;
 
     ReaderCommit(SegmentInfos infos, Directory dir) throws IOException {
       segmentsFileName = infos.getCurrentSegmentFileName();
@@ -355,6 +357,8 @@
         if (info.dir == dir)
           files.addAll(info.files());
       }
+      version = infos.getVersion();
+      generation = infos.getGeneration();
     }
     public String getSegmentsFileName() {
       return segmentsFileName;
@@ -365,6 +369,12 @@
     public Directory getDirectory() {
       return dir;
     }
+    public long getVersion() {
+      return version;
+    }
+    public long getGeneration() {
+      return generation;
+    }
   }
 
   /**
Index: src/java/org/apache/lucene/index/IndexCommit.java
===================================================================
--- src/java/org/apache/lucene/index/IndexCommit.java	(revision 658890)
+++ src/java/org/apache/lucene/index/IndexCommit.java	(working copy)
@@ -89,4 +89,17 @@
   public int hashCode() {
     return getDirectory().hashCode() + getSegmentsFileName().hashCode();
   }
+
+  /** Returns the version for this IndexCommit.  This is the
+      same value that {@link IndexReader#getVersion} would
+      return if it were opened on this commit. */
+  public long getVersion() {
+    throw new UnsupportedOperationException("This IndexCommit does not support this method.");
+  }
+
+  /** Returns the generation (the _N in segments_N) for this
+      IndexCommit */
+  public long getGeneration() {
+    throw new UnsupportedOperationException("This IndexCommit does not support this method.");
+  }
 }
Index: src/java/org/apache/lucene/index/SnapshotDeletionPolicy.java
===================================================================
--- src/java/org/apache/lucene/index/SnapshotDeletionPolicy.java	(revision 658890)
+++ src/java/org/apache/lucene/index/SnapshotDeletionPolicy.java	(working copy)
@@ -109,6 +109,12 @@
           cp.delete();
       }
     }
+    public long getVersion() {
+      return cp.getVersion();
+    }
+    public long getGeneration() {
+      return cp.getGeneration();
+    }
   }
 
   private List wrapCommits(List commits) {
Index: src/java/org/apache/lucene/index/IndexFileDeleter.java
===================================================================
--- src/java/org/apache/lucene/index/IndexFileDeleter.java	(revision 658890)
+++ src/java/org/apache/lucene/index/IndexFileDeleter.java	(working copy)
@@ -577,11 +577,15 @@
     boolean deleted;
     Directory directory;
     Collection commitsToDelete;
+    long version;
+    long generation;
 
     public CommitPoint(Collection commitsToDelete, Directory directory, SegmentInfos segmentInfos) throws IOException {
       this.directory = directory;
       this.commitsToDelete = commitsToDelete;
       segmentsFileName = segmentInfos.getCurrentSegmentFileName();
+      version = segmentInfos.getVersion();
+      generation = segmentInfos.getGeneration();
       int size = segmentInfos.size();
       files = new ArrayList(size);
       files.add(segmentsFileName);
@@ -606,6 +610,14 @@
       return directory;
     }
 
+    public long getVersion() {
+      return version;
+    }
+
+    public long getGeneration() {
+      return generation;
+    }
+
     /**
      * Called only be the deletion policy, to remove this
      * commit point from the index.