--- /dev/null	2016-10-19 15:16:42.000000000 -0700
+++ new/src/jdk.jdeps/share/classes/com/sun/tools/jdeps/ModuleGraphBuilder.java	2016-10-19 15:16:41.000000000 -0700
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2016, 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 com.sun.tools.jdeps;
+
+import java.io.PrintWriter;
+import java.lang.module.ModuleDescriptor;
+import java.util.Deque;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Stream;
+
+import static java.lang.module.ModuleDescriptor.Requires.Modifier.*;
+import static com.sun.tools.jdeps.Module.*;
+
+/**
+ * A builder to create a Graph<Module>
+ */
+public class ModuleGraphBuilder extends Graph.Builder<Module> {
+    final JdepsConfiguration config;
+
+    ModuleGraphBuilder(JdepsConfiguration config) {
+        this.config = config;
+    }
+
+    /**
+     * Adds a module to the graph.
+     */
+    ModuleGraphBuilder addModule(Module module) {
+        addNode(module);
+        return this;
+    }
+
+    /**
+     * Apply transitive reduction on the resulting graph
+     */
+    public Graph<Module> reduced() {
+        Graph<Module> graph = build();
+        // transitive reduction
+        Graph<Module> newGraph = buildGraph(graph.edges()).reduce();
+
+        if (DEBUG) {
+            PrintWriter log = new PrintWriter(System.err);
+            System.err.println("before transitive reduction: ");
+            graph.printGraph(log);
+            System.err.println("after transitive reduction: ");
+            newGraph.printGraph(log);
+        }
+
+        return newGraph;
+    }
+
+    public Graph<Module> buildGraph() {
+        Graph<Module> graph = build();
+        return buildGraph(graph.edges());
+    }
+
+    /**
+     * Build a graph of module from the given dependences.
+     *
+     * It transitively includes all implied read edges.
+     */
+    private Graph<Module> buildGraph(Map<Module, Set<Module>> edges) {
+        Graph.Builder<Module> builder = new Graph.Builder<>();
+        Set<Module> visited = new HashSet<>();
+        Deque<Module> deque = new LinkedList<>();
+        edges.entrySet().stream().forEach(e -> {
+            Module m = e.getKey();
+            deque.add(m);
+            e.getValue().stream().forEach(v -> {
+                deque.add(v);
+                builder.addEdge(m, v);
+            });
+        });
+
+        // read requires public from ModuleDescriptor
+        Module source;
+        while ((source = deque.poll()) != null) {
+            if (visited.contains(source))
+                continue;
+
+            visited.add(source);
+            builder.addNode(source);
+            Module from = source;
+            requiresPublic(from).forEach(m -> {
+                deque.add(m);
+                builder.addEdge(from, m);
+            });
+        }
+        return builder.build();
+    }
+
+    /*
+     * Returns a stream of modules upon which the given module `requires public`
+     */
+    public Stream<Module> requiresPublic(Module m) {
+        // find requires public
+        return m.descriptor()
+                .requires().stream()
+                .filter(req -> req.modifiers().contains(PUBLIC))
+                .map(ModuleDescriptor.Requires::name)
+                .map(config::findModule)
+                .flatMap(Optional::stream);
+    }
+}