--- /dev/null	Fri Sep  9 14:16:51 2011
+++ new/agent/src/share/classes/sun/jvm/hotspot/runtime/VirtualBaseConstructor.java	Fri Sep  9 14:17:12 2011
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+package sun.jvm.hotspot.runtime;
+
+import java.util.*;
+import sun.jvm.hotspot.debugger.*;
+import sun.jvm.hotspot.debugger.cdbg.CDebugger;
+import sun.jvm.hotspot.debugger.cdbg.ClosestSymbol;
+import sun.jvm.hotspot.debugger.cdbg.LoadObject;
+import sun.jvm.hotspot.types.*;
+import sun.jvm.hotspot.HotSpotTypeDataBase;
+
+/** This provides a factory to create instances where the base virtual
+ * type is know and the expected subclasses are within a particular
+ * package. */
+
+public class VirtualBaseConstructor<T> extends InstanceConstructor {
+  private TypeDataBase db;
+  private HashMap      map; // Map<String, Class>
+  private Type         baseType;
+  private Class        unknownTypeHandler;
+
+  public VirtualBaseConstructor(TypeDataBase db, Type baseType, String packageName, Class unknownTypeHandler) {
+    this.db = (HotSpotTypeDataBase)db;
+    map     = new HashMap();
+    this.baseType = baseType;
+    this.unknownTypeHandler = unknownTypeHandler;
+    // Try to find mirror types for each of the types.  If there isn't
+    // a direct mirror then try to find an instantiable superclass and
+    // treat it as that.
+    for (Iterator iter = db.getTypes(); iter.hasNext(); ) {
+      Type t = (Type) iter.next();
+      Type superType = t;
+      while (superType != null && superType != baseType) {
+        superType = superType.getSuperclass();
+      }
+      if (superType == baseType) {
+        superType = t;
+        Class c = null;
+        while (c == null && superType != null) {
+          try {
+            c = Class.forName(packageName + "." + superType.getName());
+          } catch (Exception e) {
+          }
+          if (c == null) superType = superType.getSuperclass();
+        }
+        if (c == null) {
+          c = unknownTypeHandler;
+        }
+        map.put(t.getName(), c);
+      }
+    }
+  }
+
+  /** Instantiate the most-precisely typed wrapper object available
+      for the type of the given Address. If no type in the mapping
+      matched the type of the Address, throws a WrongTypeException.
+      Returns null for a null address (similar behavior to
+      VMObjectFactory). */
+  public VMObject instantiateWrapperFor(Address addr) throws WrongTypeException {
+    if (addr == null) {
+      return null;
+    }
+
+    Type type = db.findDynamicTypeForAddress(addr, baseType);
+    if (type != null) {
+        return (VMObject) VMObjectFactory.newObject((Class) map.get(type.getName()), addr);
+    } else if (unknownTypeHandler != null) {
+        return (VMObject) VMObjectFactory.newObject(unknownTypeHandler, addr);
+    }
+
+    throw newWrongTypeException(addr);
+  }
+}