Index: IndexWriter.java
===================================================================
RCS file: /home/cvspublic/jakarta-lucene/src/java/org/apache/lucene/index/IndexWriter.java,v
retrieving revision 1.44
diff -u -r1.44 IndexWriter.java
--- IndexWriter.java	12 Dec 2004 20:26:27 -0000	1.44
+++ IndexWriter.java	18 Dec 2004 01:50:20 -0000
@@ -657,6 +657,102 @@
       }
     }
   }
+  
+  /**
+	 * Expunges the deleted documents.
+	 * Compacts and merges all segments containing deleted documents.
+	 * @throws IOException
+	 */
+	public final void expungeDeleted() throws IOException {
+		final Vector segmentsToDelete = new Vector();
+		final SegmentInfos newInfos = new SegmentInfos();
+
+		if (infoStream != null) {
+			infoStream.print("Expunging deleted documents.");
+		}
+		
+		class DeleteItem{
+			SegmentMerger merger;
+			String segmentName;
+		}
+		
+		java.util.LinkedList delItemList=new java.util.LinkedList();
+		
+		// iterate thru all the segment infos
+		for (int i = 0; i < segmentInfos.size(); i++) {
+			SegmentInfo si = segmentInfos.info(i);
+
+			Directory directory = si.dir;
+
+			if (SegmentReader.hasDeletions(si)) { // found a deletion
+
+				// make a new segment and merge itself
+				String newSegment = newSegmentName();
+
+				SegmentReader reader = SegmentReader.get(si);
+				SegmentMerger merger = new SegmentMerger(directory, newSegment);
+				merger.add(reader);
+				int newDocCount = merger.merge();
+				merger.closeReaders();
+				
+				DeleteItem item=new DeleteItem();
+				item.merger=merger;
+				item.segmentName=newSegment;
+				delItemList.add(item);
+				
+				if ((reader.directory() == this.directory) || // if we own the
+															  // directory
+						(reader.directory() == this.ramDirectory)) {
+					segmentsToDelete.add(reader);
+				}
+
+				newInfos
+						.add(new SegmentInfo(newSegment, newDocCount, directory));
+			} else {
+				newInfos.add(si);
+			}
+		}
+
+		// rewrite the segment info if there is something changed
+		if (segmentsToDelete.size() > 0) {
+			synchronized (directory) { // in- & inter-process sync
+				new Lock.With(directory.makeLock(COMMIT_LOCK_NAME),
+						COMMIT_LOCK_TIMEOUT) {
+					public Object doBody() throws IOException {
+						newInfos.write(directory); // commit before deleting
+						deleteSegments(segmentsToDelete); // delete now-unused
+														  // segments
+						return null;
+					}
+				}.run();
+			}
+		}
+		
+//		 do the compound file thing
+		if (useCompoundFile && delItemList.size()>0) {
+			synchronized(directory){
+				java.util.Iterator iter=delItemList.iterator();
+				boolean locked = false;
+				Lock lock = directory.makeLock(COMMIT_LOCK_NAME);
+				try {
+					locked = lock.obtain(COMMIT_LOCK_TIMEOUT);
+					while(iter.hasNext()){
+						DeleteItem item=(DeleteItem)iter.next();
+						Vector filesToDelete = item.merger
+						.createCompoundFile(item.segmentName + ".tmp");
+//				      make compound file visible for SegmentReaders
+						directory.renameFile(item.segmentName+ ".tmp",
+								item.segmentName + ".cfs");
+						// delete now unused files of segment
+						deleteFiles(filesToDelete);
+					}
+				} finally {
+					if (locked)
+						lock.release();
+				}
+			}
+		}
+	}
 
   /*
    * Some operating systems (e.g. Windows) don't permit a file to be deleted