--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/runtime/VirtualConstructor.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2000-2005 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.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.*;
+import sun.jvm.hotspot.types.*;
+
+/** This class provides generalized "virtual constructor"
+    functionality for VMObjects. In simple terms, it creates
+    correctly-typed Java wrapper objects for underlying Addresses,
+    using the "RTTI-like" functionality of TypeDataBase. For example,
+    if the given Address really is a DefNewGeneration*, the Java object
+    created for it will be of type
+    sun.jvm.hotspot.memory.DefNewGeneration, assuming the mapping from
+    type "DefNewGeneration" to class
+    sun.jvm.hotspot.memory.DefNewGeneration has been set up. */
+
+public class VirtualConstructor {
+  private TypeDataBase db;
+  private Map          map; // Map<String, Class>
+
+  public VirtualConstructor(TypeDataBase db) {
+    this.db = db;
+    map     = new HashMap();
+  }
+
+  /** Adds a mapping from the given C++ type name to the given Java
+      class. The latter must be a subclass of
+      sun.jvm.hotspot.runtime.VMObject. Returns false if there was
+      already a class for this type name in the map. */
+  public boolean addMapping(String cTypeName, Class clazz) {
+    if (map.get(cTypeName) != null) {
+      return false;
+    }
+
+    map.put(cTypeName, clazz);
+    return true;
+  }
+
+  /** 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;
+    }
+
+    for (Iterator iter = map.keySet().iterator(); iter.hasNext(); ) {
+      String typeName = (String) iter.next();
+      if (db.addressTypeIsEqualToType(addr, db.lookupType(typeName))) {
+        return (VMObject) VMObjectFactory.newObject((Class) map.get(typeName), addr);
+      }
+    }
+
+    String message = "No suitable match for type of address " + addr;
+    CDebugger cdbg = VM.getVM().getDebugger().getCDebugger();
+    if (cdbg != null) {
+      // Most common case: V-table pointer is the first field
+      Address vtblPtr = addr.getAddressAt(0);
+      LoadObject lo = cdbg.loadObjectContainingPC(vtblPtr);
+      if (lo != null) {
+        ClosestSymbol symbol = lo.closestSymbolToPC(vtblPtr);
+        if (symbol != null) {
+          message += " (nearest symbol is " + symbol.getName() + ")";
+        }
+      }
+    }
+
+    throw new WrongTypeException(message);
+  }
+}