Index: src/java/org/apache/lucene/index/MultiReader.java
===================================================================
--- src/java/org/apache/lucene/index/MultiReader.java	(revision 611183)
+++ src/java/org/apache/lucene/index/MultiReader.java	(working copy)
@@ -39,6 +39,7 @@
   private Hashtable normsCache = new Hashtable();
   private int maxDoc = 0;
   private int numDocs = -1;
+  private int numDeletedDocs = -1;
   private boolean hasDeletions = false;
   
  /**
@@ -203,6 +204,16 @@
     return numDocs;
   }
 
+  public synchronized int numDeletedDocs() {
+	// Don't call ensureOpen() here (it could affect performance)
+	if (numDeletedDocs == -1) {
+	  for (int i = 0; i < subReaders.length; i++) {
+		numDeletedDocs += subReaders[i].numDeletedDocs();
+	  }
+	}
+	return numDeletedDocs;
+  }
+	  
   public int maxDoc() {
     // Don't call ensureOpen() here (it could affect performance)
     return maxDoc;
@@ -228,6 +239,7 @@
 
   protected void doDelete(int n) throws CorruptIndexException, IOException {
     numDocs = -1;                             // invalidate cache
+    numDeletedDocs = -1;                      // invalidate cache
     int i = readerIndex(n);                   // find segment num
     subReaders[i].deleteDocument(n - starts[i]);      // dispatch to segment reader
     hasDeletions = true;
@@ -238,7 +250,8 @@
       subReaders[i].undeleteAll();
 
     hasDeletions = false;
-    numDocs = -1;                                 // invalidate cache
+    numDocs = -1;                             // invalidate cache
+    numDeletedDocs = -1;                      // invalidate cache
   }
 
   private int readerIndex(int n) {    // find reader for doc n:
Index: src/java/org/apache/lucene/index/FilterIndexReader.java
===================================================================
--- src/java/org/apache/lucene/index/FilterIndexReader.java	(revision 611183)
+++ src/java/org/apache/lucene/index/FilterIndexReader.java	(working copy)
@@ -137,6 +137,11 @@
     return in.numDocs();
   }
 
+  public int numDeletedDocs() {
+    // Don't call ensureOpen() here (it could affect performance)
+    return in.numDeletedDocs();
+  }
+  
   public int maxDoc() {
     // Don't call ensureOpen() here (it could affect performance)
     return in.maxDoc();
Index: src/java/org/apache/lucene/index/ParallelReader.java
===================================================================
--- src/java/org/apache/lucene/index/ParallelReader.java	(revision 611183)
+++ src/java/org/apache/lucene/index/ParallelReader.java	(working copy)
@@ -53,6 +53,7 @@
 
   private int maxDoc;
   private int numDocs;
+  private int numDeletedDocs;
   private boolean hasDeletions;
 
  /** Construct a ParallelReader. 
@@ -94,6 +95,7 @@
     if (readers.size() == 0) {
       this.maxDoc = reader.maxDoc();
       this.numDocs = reader.numDocs();
+      this.numDeletedDocs = reader.numDeletedDocs();
       this.hasDeletions = reader.hasDeletions();
     }
 
@@ -214,6 +216,11 @@
     return numDocs;
   }
 
+  public int numDeletedDocs() {
+    // Don't call ensureOpen() here (it could affect performance)
+	return numDeletedDocs;
+  }
+  
   public int maxDoc() {
     // Don't call ensureOpen() here (it could affect performance)
     return maxDoc;
Index: src/java/org/apache/lucene/index/SegmentReader.java
===================================================================
--- src/java/org/apache/lucene/index/SegmentReader.java	(revision 611183)
+++ src/java/org/apache/lucene/index/SegmentReader.java	(working copy)
@@ -690,6 +690,11 @@
     return n;
   }
 
+  public int numDeletedDocs() {
+    // Don't call ensureOpen() here (it could affect performance)
+	return deletedDocs == null ? 0 : deletedDocs.count();
+  }
+  
   public int maxDoc() {
     // Don't call ensureOpen() here (it could affect performance)
     return si.docCount;
Index: src/java/org/apache/lucene/index/IndexReader.java
===================================================================
--- src/java/org/apache/lucene/index/IndexReader.java	(revision 611183)
+++ src/java/org/apache/lucene/index/IndexReader.java	(working copy)
@@ -509,6 +509,9 @@
   /** Returns the number of documents in this index. */
   public abstract int numDocs();
 
+  /** Returns the number of deleted documents in this index. */
+  public abstract int numDeletedDocs();
+  
   /** Returns one greater than the largest possible document number.
    * This may be used to, e.g., determine how big to allocate an array which
    * will have an element for every document number in an index.
Index: src/java/org/apache/lucene/index/MultiSegmentReader.java
===================================================================
--- src/java/org/apache/lucene/index/MultiSegmentReader.java	(revision 611183)
+++ src/java/org/apache/lucene/index/MultiSegmentReader.java	(working copy)
@@ -39,6 +39,7 @@
   private Hashtable normsCache = new Hashtable();
   private int maxDoc = 0;
   private int numDocs = -1;
+  private int numDeletedDocs = -1;
   private boolean hasDeletions = false;
 
   /** Construct reading the named set of readers. */
@@ -245,6 +246,16 @@
     return numDocs;
   }
 
+  public synchronized int numDeletedDocs() {
+	// Don't call ensureOpen() here (it could affect performance)
+	if (numDeletedDocs == -1) {
+	  for (int i = 0; i < subReaders.length; i++) {
+		numDeletedDocs += subReaders[i].numDeletedDocs();
+	  }
+	}
+	return numDeletedDocs;
+  }
+		  
   public int maxDoc() {
     // Don't call ensureOpen() here (it could affect performance)
     return maxDoc;
@@ -270,6 +281,7 @@
 
   protected void doDelete(int n) throws CorruptIndexException, IOException {
     numDocs = -1;                             // invalidate cache
+    numDeletedDocs = -1;                      // invalidate cache
     int i = readerIndex(n);                   // find segment num
     subReaders[i].deleteDocument(n - starts[i]);      // dispatch to segment reader
     hasDeletions = true;
@@ -281,6 +293,7 @@
 
     hasDeletions = false;
     numDocs = -1;                                 // invalidate cache
+    numDeletedDocs = -1;                                 // invalidate cache
   }
 
   private int readerIndex(int n) {    // find reader for doc n: