--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/types/basic/BasicVtblAccess.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2002-2005 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.types.basic;
+
+import java.util.*;
+
+import sun.jvm.hotspot.debugger.*;
+import sun.jvm.hotspot.types.*;
+
+public abstract class BasicVtblAccess implements VtblAccess {
+  protected SymbolLookup symbolLookup;
+  protected String[] dllNames;
+
+  private Map typeToVtblMap = new HashMap();
+
+  public BasicVtblAccess(SymbolLookup symbolLookup,
+                         String[] dllNames) {
+    this.symbolLookup = symbolLookup;
+    this.dllNames = dllNames;
+  }
+
+  static Object nullAddress = new Object();
+
+  public Address getVtblForType(Type type) {
+    if (type == null) {
+      return null;
+    }
+    Object result = typeToVtblMap.get(type);
+    if (result == nullAddress) {
+        return null;
+    }
+    if (result != null) {
+      return (Address)result;
+    }
+    String vtblSymbol = vtblSymbolForType(type);
+    if (vtblSymbol == null) {
+      typeToVtblMap.put(type, nullAddress);
+      return null;
+    }
+    for (int i = 0; i < dllNames.length; i++) {
+      Address addr = symbolLookup.lookup(dllNames[i], vtblSymbol);
+      if (addr != null) {
+        typeToVtblMap.put(type, addr);
+        return addr;
+      }
+    }
+    typeToVtblMap.put(type, nullAddress);
+    return null;
+  }
+
+  public void clearCaches() {
+    typeToVtblMap.clear();
+  }
+
+  protected abstract String vtblSymbolForType(Type type);
+}