• file
• revisions
• annotate
• diff
• comparison
• raw

src/share/classes/com/sun/tools/javac/util/GraphUtils.java@2eb010b6cb22 (annotated)

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

Thu, 31 Aug 2017 15:17:03 +0800

author

aoqi

date

Thu, 31 Aug 2017 15:17:03 +0800

changeset 2525

2eb010b6cb22

parent 2047

5f915a0c9615

parent 0

959103a6100f

child 3295

859dc787b52b

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation. Oracle designates this
aoqi@0	8	* particular file as subject to the "Classpath" exception as provided
aoqi@0	9	* by Oracle in the LICENSE file that accompanied this code.
aoqi@0	10	*
aoqi@0	11	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	12	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	13	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	14	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	15	* accompanied this code).
aoqi@0	16	*
aoqi@0	17	* You should have received a copy of the GNU General Public License version
aoqi@0	18	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	19	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	20	*
aoqi@0	21	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	22	* or visit www.oracle.com if you need additional information or have any
aoqi@0	23	* questions.
aoqi@0	24	*/
aoqi@0	25
aoqi@0	26	package com.sun.tools.javac.util;
aoqi@0	27
aoqi@0	28	/** <p><b>This is NOT part of any supported API.
aoqi@0	29	* If you write code that depends on this, you do so at your own risk.
aoqi@0	30	* This code and its internal interfaces are subject to change or
aoqi@0	31	* deletion without notice.</b>
aoqi@0	32	*/
aoqi@0	33	public class GraphUtils {
aoqi@0	34
aoqi@0	35	/**
aoqi@0	36	* Basic interface for defining various dependency kinds. All dependency kinds
aoqi@0	37	* must at least support basic capabilities to tell the DOT engine how to render them.
aoqi@0	38	*/
aoqi@0	39	public interface DependencyKind {
aoqi@0	40	/**
aoqi@0	41	* Returns the DOT representation (to be used in a {@code style} attribute
aoqi@0	42	* that's most suited for this dependency kind.
aoqi@0	43	*/
aoqi@0	44	String getDotStyle();
aoqi@0	45	}
aoqi@0	46
aoqi@0	47	/**
aoqi@0	48	* This class is a basic abstract class for representing a node.
aoqi@0	49	* A node is associated with a given data.
aoqi@0	50	*/
aoqi@0	51	public static abstract class Node<D> {
aoqi@0	52	public final D data;
aoqi@0	53
aoqi@0	54	public Node(D data) {
aoqi@0	55	this.data = data;
aoqi@0	56	}
aoqi@0	57
aoqi@0	58	/**
aoqi@0	59	* Get an array of the dependency kinds supported by this node.
aoqi@0	60	*/
aoqi@0	61	public abstract DependencyKind[] getSupportedDependencyKinds();
aoqi@0	62
aoqi@0	63	/**
aoqi@0	64	* Get all dependencies, regardless of their kind.
aoqi@0	65	*/
aoqi@0	66	public abstract Iterable<? extends Node<D>> getAllDependencies();
aoqi@0	67
aoqi@0	68	/**
aoqi@0	69	* Get a name for the dependency (of given kind) linking this node to a given node
aoqi@0	70	*/
aoqi@0	71	public abstract String getDependencyName(Node<D> to, DependencyKind dk);
aoqi@0	72
aoqi@0	73	@Override
aoqi@0	74	public String toString() {
aoqi@0	75	return data.toString();
aoqi@0	76	}
aoqi@0	77	}
aoqi@0	78
aoqi@0	79	/**
aoqi@0	80	* This class specialized Node, by adding elements that are required in order
aoqi@0	81	* to perform Tarjan computation of strongly connected components.
aoqi@0	82	*/
aoqi@0	83	public static abstract class TarjanNode<D> extends Node<D> implements Comparable<TarjanNode<D>> {
aoqi@0	84	int index = -1;
aoqi@0	85	int lowlink;
aoqi@0	86	boolean active;
aoqi@0	87
aoqi@0	88	public TarjanNode(D data) {
aoqi@0	89	super(data);
aoqi@0	90	}
aoqi@0	91
aoqi@0	92	public abstract Iterable<? extends TarjanNode<D>> getAllDependencies();
aoqi@0	93
aoqi@0	94	public abstract Iterable<? extends TarjanNode<D>> getDependenciesByKind(DependencyKind dk);
aoqi@0	95
aoqi@0	96	public int compareTo(TarjanNode<D> o) {
aoqi@0	97	return (index < o.index) ? -1 : (index == o.index) ? 0 : 1;
aoqi@0	98	}
aoqi@0	99	}
aoqi@0	100
aoqi@0	101	/**
aoqi@0	102	* Tarjan's algorithm to determine strongly connected components of a
aoqi@0	103	* directed graph in linear time. Works on TarjanNode.
aoqi@0	104	*/
aoqi@0	105	public static <D, N extends TarjanNode<D>> List<? extends List<? extends N>> tarjan(Iterable<? extends N> nodes) {
aoqi@0	106	ListBuffer<List<N>> cycles = new ListBuffer<>();
aoqi@0	107	ListBuffer<N> stack = new ListBuffer<>();
aoqi@0	108	int index = 0;
aoqi@0	109	for (N node: nodes) {
aoqi@0	110	if (node.index == -1) {
aoqi@0	111	index += tarjan(node, index, stack, cycles);
aoqi@0	112	}
aoqi@0	113	}
aoqi@0	114	return cycles.toList();
aoqi@0	115	}
aoqi@0	116
aoqi@0	117	private static <D, N extends TarjanNode<D>> int tarjan(N v, int index, ListBuffer<N> stack, ListBuffer<List<N>> cycles) {
aoqi@0	118	v.index = index;
aoqi@0	119	v.lowlink = index;
aoqi@0	120	index++;
aoqi@0	121	stack.prepend(v);
aoqi@0	122	v.active = true;
aoqi@0	123	for (TarjanNode<D> nd: v.getAllDependencies()) {
aoqi@0	124	@SuppressWarnings("unchecked")
aoqi@0	125	N n = (N)nd;
aoqi@0	126	if (n.index == -1) {
aoqi@0	127	tarjan(n, index, stack, cycles);
aoqi@0	128	v.lowlink = Math.min(v.lowlink, n.lowlink);
aoqi@0	129	} else if (stack.contains(n)) {
aoqi@0	130	v.lowlink = Math.min(v.lowlink, n.index);
aoqi@0	131	}
aoqi@0	132	}
aoqi@0	133	if (v.lowlink == v.index) {
aoqi@0	134	N n;
aoqi@0	135	ListBuffer<N> cycle = new ListBuffer<>();
aoqi@0	136	do {
aoqi@0	137	n = stack.remove();
aoqi@0	138	n.active = false;
aoqi@0	139	cycle.add(n);
aoqi@0	140	} while (n != v);
aoqi@0	141	cycles.add(cycle.toList());
aoqi@0	142	}
aoqi@0	143	return index;
aoqi@0	144	}
aoqi@0	145
aoqi@0	146	/**
aoqi@0	147	* Debugging: dot representation of a set of connected nodes. The resulting
aoqi@0	148	* dot representation will use {@code Node.toString} to display node labels
aoqi@0	149	* and {@code Node.printDependency} to display edge labels. The resulting
aoqi@0	150	* representation is also customizable with a graph name and a header.
aoqi@0	151	*/
aoqi@0	152	public static <D> String toDot(Iterable<? extends TarjanNode<D>> nodes, String name, String header) {
aoqi@0	153	StringBuilder buf = new StringBuilder();
aoqi@0	154	buf.append(String.format("digraph %s {\n", name));
aoqi@0	155	buf.append(String.format("label = \"%s\";\n", header));
aoqi@0	156	//dump nodes
aoqi@0	157	for (TarjanNode<D> n : nodes) {
aoqi@0	158	buf.append(String.format("%s [label = \"%s\"];\n", n.hashCode(), n.toString()));
aoqi@0	159	}
aoqi@0	160	//dump arcs
aoqi@0	161	for (TarjanNode<D> from : nodes) {
aoqi@0	162	for (DependencyKind dk : from.getSupportedDependencyKinds()) {
aoqi@0	163	for (TarjanNode<D> to : from.getDependenciesByKind(dk)) {
aoqi@0	164	buf.append(String.format("%s -> %s [label = \" %s \" style = %s ];\n",
aoqi@0	165	from.hashCode(), to.hashCode(), from.getDependencyName(to, dk), dk.getDotStyle()));
aoqi@0	166	}
aoqi@0	167	}
aoqi@0	168	}
aoqi@0	169	buf.append("}\n");
aoqi@0	170	return buf.toString();
aoqi@0	171	}
aoqi@0	172	}