jdk8-mips64-public/langtools: src/share/classes/com/sun/tools/javac/util/GraphUtils.java@af8417e590f4 (annotated)

src/share/classes/com/sun/tools/javac/util/GraphUtils.java@af8417e590f4 (annotated)

src/share/classes/com/sun/tools/javac/util/GraphUtils.java

Sun, 17 Feb 2013 16:44:55 -0500

author: dholmes
date: Sun, 17 Feb 2013 16:44:55 -0500
changeset 1571: af8417e590f4
parent 1562: 2154ed9ff6c8
child 2000: 4a6acc42c3a1
permissions: -rw-r--r--

Merge

 /*
  * Copyright (c) 1999, 2013, 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.javac.util;
 /** <p><b>This is NOT part of any supported API.
  *  If you write code that depends on this, you do so at your own risk.
  *  This code and its internal interfaces are subject to change or
  *  deletion without notice.</b>
  */
 public class GraphUtils {
     /**
      * This class is a basic abstract class for representing a node.
      * A node is associated with a given data.
      */
     public static abstract class Node<D> {
         public final D data;
         public Node(D data) {
             this.data = data;
         }
         public abstract Iterable<? extends Node<D>> getDependencies();
         public abstract String printDependency(Node<D> to);
         @Override
         public String toString() {
             return data.toString();
         }
     }
     /**
      * This class specialized Node, by adding elements that are required in order
      * to perform Tarjan computation of strongly connected components.
      */
     public static abstract class TarjanNode<D> extends Node<D> implements Comparable<TarjanNode<D>> {
         int index = -1;
         int lowlink;
         boolean active;
         public TarjanNode(D data) {
             super(data);
         }
         public abstract Iterable<? extends TarjanNode<D>> getDependencies();
         public int compareTo(TarjanNode<D> o) {
             return (index < o.index) ? -1 : (index == o.index) ? 0 : 1;
         }
     }
     /**
      * Tarjan's algorithm to determine strongly connected components of a
      * directed graph in linear time. Works on TarjanNode.
      */
     public static <D, N extends TarjanNode<D>> List<? extends List<? extends N>> tarjan(Iterable<? extends N> nodes) {
         ListBuffer<List<N>> cycles = ListBuffer.lb();
         ListBuffer<N> stack = ListBuffer.lb();
         int index = 0;
         for (N node: nodes) {
             if (node.index == -1) {
                 index += tarjan(node, index, stack, cycles);
             }
         }
         return cycles.toList();
     }
     private static <D, N extends TarjanNode<D>> int tarjan(N v, int index, ListBuffer<N> stack, ListBuffer<List<N>> cycles) {
         v.index = index;
         v.lowlink = index;
         index++;
         stack.prepend(v);
         v.active = true;
         for (TarjanNode<D> nd: v.getDependencies()) {
             @SuppressWarnings("unchecked")
             N n = (N)nd;
             if (n.index == -1) {
                 tarjan(n, index, stack, cycles);
                 v.lowlink = Math.min(v.lowlink, n.lowlink);
             } else if (stack.contains(n)) {
                 v.lowlink = Math.min(v.lowlink, n.index);
             }
         }
         if (v.lowlink == v.index) {
             N n;
             ListBuffer<N> cycle = ListBuffer.lb();
             do {
                 n = stack.remove();
                 n.active = false;
                 cycle.add(n);
             } while (n != v);
             cycles.add(cycle.toList());
         }
         return index;
     }
     /**
      * Debugging: dot representation of a set of connected nodes. The resulting
      * dot representation will use {@code Node.toString} to display node labels
      * and {@code Node.printDependency} to display edge labels. The resulting
      * representation is also customizable with a graph name and a header.
      */
     public static <D> String toDot(Iterable<? extends TarjanNode<D>> nodes, String name, String header) {
         StringBuilder buf = new StringBuilder();
         buf.append(String.format("digraph %s {\n", name));
         buf.append(String.format("label = \"%s\";\n", header));
         //dump nodes
         for (TarjanNode<D> n : nodes) {
             buf.append(String.format("%s [label = \"%s\"];\n", n.hashCode(), n.toString()));
         }
         //dump arcs
         for (TarjanNode<D> from : nodes) {
             for (TarjanNode<D> to : from.getDependencies()) {
                 buf.append(String.format("%s -> %s [label = \" %s \"];\n",
                         from.hashCode(), to.hashCode(), from.printDependency(to)));
             }
         }
         buf.append("}\n");
         return buf.toString();
     }
 }

Mercurial > jdk8-mips64-public > langtools / annotate

src/share/classes/com/sun/tools/javac/util/GraphUtils.java@af8417e590f4 (annotated)

src/share/classes/com/sun/tools/javac/util/GraphUtils.java