Index: src/test/org/apache/lucene/index/TestTermVectorsReader.java
===================================================================
--- src/test/org/apache/lucene/index/TestTermVectorsReader.java	(revision 590149)
+++ src/test/org/apache/lucene/index/TestTermVectorsReader.java	(working copy)
@@ -329,6 +329,32 @@
       }
     }
 
+    // test setDocumentNumber()
+    IndexReader ir = IndexReader.open(dir);
+    DocNumAwareMapper docNumAwareMapper = new DocNumAwareMapper();
+    assertEquals(-1, docNumAwareMapper.getDocumentNumber());
+
+    ir.getTermFreqVector(0, docNumAwareMapper);
+    assertEquals(0, docNumAwareMapper.getDocumentNumber());
+    docNumAwareMapper.setDocumentNumber(-1);
+
+    ir.getTermFreqVector(1, docNumAwareMapper);
+    assertEquals(1, docNumAwareMapper.getDocumentNumber());
+    docNumAwareMapper.setDocumentNumber(-1);
+
+    ir.getTermFreqVector(0, "f1", docNumAwareMapper);
+    assertEquals(0, docNumAwareMapper.getDocumentNumber());
+    docNumAwareMapper.setDocumentNumber(-1);
+
+    ir.getTermFreqVector(1, "f2", docNumAwareMapper);
+    assertEquals(1, docNumAwareMapper.getDocumentNumber());
+    docNumAwareMapper.setDocumentNumber(-1);
+
+    ir.getTermFreqVector(0, "f1", docNumAwareMapper);
+    assertEquals(0, docNumAwareMapper.getDocumentNumber());
+
+    ir.close();
+
   }
 
 
@@ -364,4 +390,33 @@
       fail();
     }
   }
+
+
+  public static class DocNumAwareMapper extends TermVectorMapper {
+
+    public DocNumAwareMapper() {
+    }
+
+    private int documentNumber = -1;
+
+    public void setExpectations(String field, int numTerms, boolean storeOffsets, boolean storePositions) {
+      if (documentNumber == -1) {
+        throw new RuntimeException("Documentnumber should be set at this point!");
+      }
+    }
+
+    public void map(String term, int frequency, TermVectorOffsetInfo[] offsets, int[] positions) {
+      if (documentNumber == -1) {
+        throw new RuntimeException("Documentnumber should be set at this point!");
+      }
+    }
+
+    public int getDocumentNumber() {
+      return documentNumber;
+    }
+
+    public void setDocumentNumber(int documentNumber) {
+      this.documentNumber = documentNumber;
+    }
+  }
 }
Index: src/java/org/apache/lucene/index/TermVectorMapper.java
===================================================================
--- src/java/org/apache/lucene/index/TermVectorMapper.java	(revision 590149)
+++ src/java/org/apache/lucene/index/TermVectorMapper.java	(working copy)
@@ -85,4 +85,12 @@
     return ignoringOffsets;
   }
 
+  /**
+   * Passes down the index of the document whose term vector is currently beeing mapped,
+   * once for each top level call to a term vector reader.
+   * @param documentNumber index of document currently beeing mapped
+   */
+  public void setDocumentNumber(int documentNumber) {
+  }
+
 }
Index: src/java/org/apache/lucene/index/TermVectorsReader.java
===================================================================
--- src/java/org/apache/lucene/index/TermVectorsReader.java	(revision 590149)
+++ src/java/org/apache/lucene/index/TermVectorsReader.java	(working copy)
@@ -163,6 +163,7 @@
         for (int i = 0; i <= found; i++)
           position += tvd.readVLong();
 
+        mapper.setDocumentNumber(docNum);
         readTermVector(field, position, mapper);
       } else {
         //System.out.println("Fieldable not found");
@@ -228,7 +229,7 @@
           tvfPointers[i] = position;
         }
 
-        result = readTermVectors(fields, tvfPointers);
+        result = readTermVectors(docNum, fields, tvfPointers);
       }
     } else {
       //System.out.println("No tvx file");
@@ -268,6 +269,7 @@
           tvfPointers[i] = position;
         }
 
+        mapper.setDocumentNumber(docNumber);
         readTermVectors(fields, tvfPointers, mapper);
       }
     } else {
@@ -276,12 +278,13 @@
   }
 
 
-  private SegmentTermVector[] readTermVectors(String fields[], long tvfPointers[])
+  private SegmentTermVector[] readTermVectors(int docNum, String fields[], long tvfPointers[])
           throws IOException {
     SegmentTermVector res[] = new SegmentTermVector[fields.length];
     for (int i = 0; i < fields.length; i++) {
       ParallelArrayTermVectorMapper mapper = new ParallelArrayTermVectorMapper();
-       readTermVector(fields[i], tvfPointers[i], mapper);
+      mapper.setDocumentNumber(docNum);
+      readTermVector(fields[i], tvfPointers[i], mapper);
       res[i] = (SegmentTermVector) mapper.materializeVector();
     }
     return res;