--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/text/undo/DocumentUndoManagerRegistry.d	Sat Aug 23 19:10:48 2008 +0200
@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2008 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwtx.text.undo.DocumentUndoManagerRegistry;
+
+import dwt.dwthelper.utils;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import dwtx.core.runtime.Assert;
+import dwtx.jface.text.IDocument;
+
+
+/**
+ * This document undo manager registry provides access to a document's
+ * undo manager. In order to connect a document a document undo manager
+ * call <code>connect</code>. After that call has successfully completed
+ * undo manager can be obtained via <code>getDocumentUndoManager</code>.
+ * The undo manager is created on the first connect and disposed on the last
+ * disconnect, i.e. this registry keeps track of how often a undo manager is
+ * connected and returns the same undo manager to each client as long as the
+ * document is connected.
+ * <p>
+ * <em>The recoding of changes starts with the first {@link #connect(IDocument)}.</em></p>
+ *
+ * @since 3.2
+ * @noinstantiate This class is not intended to be instantiated by clients.
+ */
+public final class DocumentUndoManagerRegistry {
+    
+    private static final class Record {
+        public Record(IDocument document) {
+            count= 0;
+            undoManager= new DocumentUndoManager(document);
+        }
+        private int count;
+        private IDocumentUndoManager undoManager;
+    }
+    
+    private static Map fgFactory= new HashMap();
+    
+    private DocumentUndoManagerRegistry() {
+        //  Do not instantiate  
+    }
+
+    
+    /**
+     * Connects the file at the given location to this manager. After that call
+     * successfully completed it is guaranteed that each call to <code>getFileBuffer</code>
+     * returns the same file buffer until <code>disconnect</code> is called.
+     * <p>
+     * <em>The recoding of changes starts with the first {@link #connect(IDocument)}.</em></p>
+     *
+     * @param document the document to be connected
+     */
+    public static synchronized void connect(IDocument document) {
+        Assert.isNotNull(document);
+        Record record= (Record)fgFactory.get(document);
+        if (record is null) {
+            record= new Record(document);
+            fgFactory.put(document, record);
+        }
+        record.count++;
+    }
+
+    /**
+     * Disconnects the given document from this registry.
+     *
+     * @param document the document to be disconnected
+     */
+    public static synchronized void disconnect(IDocument document) {
+        Assert.isNotNull(document);
+        Record record= (Record)fgFactory.get(document);
+        record.count--;
+        if (record.count is 0)
+            fgFactory.remove(document);
+            
+    }
+
+    /**
+     * Returns the file buffer managed for the given location or <code>null</code>
+     * if there is no such file buffer.
+     * <p>
+     * The provided location is either a full path of a workspace resource or
+     * an absolute path in the local file system. The file buffer manager does
+     * not resolve the location of workspace resources in the case of linked
+     * resources.
+     * </p>
+     *
+     * @param document the document for which to get its undo manager
+     * @return the document undo manager or <code>null</code>
+     */
+    public static synchronized IDocumentUndoManager getDocumentUndoManager(IDocument document) {
+        Assert.isNotNull(document);
+        Record record= (Record)fgFactory.get(document);
+        if (record is null)
+            return null;
+        return record.undoManager;
+    }
+
+}