diff -r 6dc10c88c07a -r 91c05eb19277 langtools/test/tools/javac/defaultMethods/fd/shapegen/TTNode.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/defaultMethods/fd/shapegen/TTNode.java	Sun Nov 04 10:59:42 2012 +0000
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2012, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 shapegen;
+
+import shapegen.ClassCase.Kind;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+import static shapegen.ClassCase.Kind.*;
+
+/**
+ * Type Template Node
+ *
+ * @author Robert Field
+ */
+public class TTNode {
+
+    final List<TTNode> supertypes;
+    final boolean canBeClass;
+
+    private int currentKindIndex;
+    private Kind[] kinds;
+
+    public TTNode(List<TTNode> subtypes, boolean canBeClass) {
+        this.supertypes = subtypes;
+        this.canBeClass = canBeClass;
+    }
+
+    public void start(boolean includeClasses) {
+        kinds =
+             supertypes.isEmpty()?
+                (new Kind[]{IDEFAULT, IPRESENT})
+             :  ((includeClasses && canBeClass)?
+                  new Kind[]{CNONE, IVAC, IDEFAULT, IPRESENT}
+                : new Kind[]{IVAC, IDEFAULT, IPRESENT});
+        currentKindIndex = 0;
+
+        for (TTNode sub : supertypes) {
+            sub.start(includeClasses);
+        }
+    }
+
+    public boolean next() {
+        ++currentKindIndex;
+        if (currentKindIndex >= kinds.length) {
+            currentKindIndex = 0;
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+    public void collectAllSubtypes(Set<TTNode> subs) {
+        subs.add(this);
+        for (TTNode n : supertypes) {
+            n.collectAllSubtypes(subs);
+        }
+    }
+
+    private Kind getKind() {
+        return kinds[currentKindIndex];
+    }
+
+    boolean isInterface() {
+        return getKind().isInterface;
+    }
+
+    boolean isClass() {
+        return !isInterface();
+    }
+
+    boolean hasDefault() {
+        return getKind() == IDEFAULT;
+    }
+
+    public boolean isValid() {
+        for (TTNode n : supertypes) {
+            if (!n.isValid() || (isInterface() && n.isClass())) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public ClassCase genCase() {
+        ClassCase subclass;
+        List<TTNode> ttintfs;
+        if (isClass() && !supertypes.isEmpty() && supertypes.get(0).isClass()) {
+            subclass = supertypes.get(0).genCase();
+            ttintfs = supertypes.subList(1, supertypes.size());
+        } else {
+            subclass = null;
+            ttintfs = supertypes;
+        }
+        List<ClassCase> intfs = new ArrayList<>();
+        for (TTNode node : ttintfs) {
+            intfs.add(node.genCase());
+        }
+        return new ClassCase(getKind(), subclass, intfs);
+    }
+}