org.jgrapht.nio.dot.DOTExporter Maven / Gradle / Ivy
/*
* (C) Copyright 2006-2020, by Trevor Harmon and Contributors.
*
* JGraphT : a free Java graph-theory library
*
* See the CONTRIBUTORS.md file distributed with this work for additional
* information regarding copyright ownership.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the
* GNU Lesser General Public License v2.1 or later
* which is available at
* http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html.
*
* SPDX-License-Identifier: EPL-2.0 OR LGPL-2.1-or-later
*/
package org.jgrapht.nio.dot;
import org.jgrapht.*;
import org.jgrapht.nio.*;
import java.io.*;
import java.util.*;
import java.util.Map.*;
import java.util.function.*;
import java.util.regex.*;
/**
* Exports a graph into a DOT file.
*
*
* For a description of the format see
* http://en.wikipedia.org/wiki/DOT_language.
*
*
* The user can adjust the behavior using the various providers.
*
* @param the graph vertex type
* @param the graph edge type
*
* @author Trevor Harmon
* @author Dimitrios Michail
*/
public class DOTExporter
extends
BaseExporter
implements
GraphExporter
{
/**
* Default graph id used by the exporter.
*/
public static final String DEFAULT_GRAPH_ID = "G";
private static final String INDENT = " ";
private final Map validatedIds;
/**
* Constructs a new DOTExporter object with an integer id provider.
*/
public DOTExporter()
{
this(new IntegerIdProvider<>());
}
/**
* Constructs a new DOTExporter object with the given id provider. Additional providers such as
* attributes can be given using the appropriate setter methods.
*
* @param vertexIdProvider for generating vertex IDs. Must not be null.
*/
public DOTExporter(Function vertexIdProvider)
{
super(vertexIdProvider);
this.validatedIds = new HashMap<>();
}
/**
* Exports a graph into a plain text file in DOT format.
*
* @param g the graph to be exported
* @param writer the writer to which the graph to be exported
*/
@Override
public void exportGraph(Graph g, Writer writer)
{
PrintWriter out = new PrintWriter(writer);
out.println(computeHeader(g));
// graph attributes
for (Entry attr : graphAttributeProvider
.orElse(() -> Collections.emptyMap()).get().entrySet())
{
out.print(INDENT);
out.print(attr.getKey());
out.print('=');
out.print(attr.getValue());
out.println(";");
}
// vertex set
for (V v : g.vertexSet()) {
out.print(INDENT);
out.print(getVertexID(v));
getVertexAttributes(v).ifPresent(m -> {
renderAttributes(out, m);
});
out.println(";");
}
String connector = computeConnector(g);
// edge set
for (E e : g.edgeSet()) {
String source = getVertexID(g.getEdgeSource(e));
String target = getVertexID(g.getEdgeTarget(e));
out.print(INDENT);
out.print(source);
out.print(connector);
out.print(target);
getEdgeAttributes(e).ifPresent(m -> {
renderAttributes(out, m);
});
out.println(";");
}
out.println(computeFooter(g));
out.flush();
}
/**
* Compute the header
*
* @param graph the graph
* @return the header
*/
private String computeHeader(Graph graph)
{
StringBuilder headerBuilder = new StringBuilder();
if (!graph.getType().isAllowingMultipleEdges()) {
headerBuilder.append(DOTUtils.DONT_ALLOW_MULTIPLE_EDGES_KEYWORD).append(" ");
}
if (graph.getType().isDirected()) {
headerBuilder.append(DOTUtils.DIRECTED_GRAPH_KEYWORD);
} else {
headerBuilder.append(DOTUtils.UNDIRECTED_GRAPH_KEYWORD);
}
headerBuilder.append(" ").append(computeGraphId(graph)).append(" {");
return headerBuilder.toString();
}
/**
* Compute the footer
*
* @param graph the graph
* @return the footer
*/
private String computeFooter(Graph graph)
{
return "}";
}
/**
* Compute the connector
*
* @param graph the graph
* @return the connector
*/
private String computeConnector(Graph graph)
{
StringBuilder connectorBuilder = new StringBuilder();
if (graph.getType().isDirected()) {
connectorBuilder.append(" ").append(DOTUtils.DIRECTED_GRAPH_EDGEOP).append(" ");
} else {
connectorBuilder.append(" ").append(DOTUtils.UNDIRECTED_GRAPH_EDGEOP).append(" ");
}
return connectorBuilder.toString();
}
/**
* Get the id of the graph.
*
* @param graph the graph
* @return the graph id
*/
private String computeGraphId(Graph graph)
{
String graphId = getGraphId().orElse(DEFAULT_GRAPH_ID);
if (!DOTUtils.isValidID(graphId)) {
throw new ExportException(
"Generated graph ID '" + graphId
+ "' is not valid with respect to the .dot language");
}
return graphId;
}
private void renderAttributes(PrintWriter out, Map attributes)
{
if (attributes == null) {
return;
}
out.print(" [ ");
final Attribute labelAttribute = attributes.get("label");
if (labelAttribute != null) {
renderAttribute(out, "label", labelAttribute);
}
if (attributes != null) {
for (Map.Entry entry : attributes.entrySet()) {
String name = entry.getKey();
if (name.equals("label")) {
// already handled by special case above
continue;
}
renderAttribute(out, name, entry.getValue());
}
}
out.print("]");
}
private void renderAttribute(PrintWriter out, String attrName, Attribute attribute)
{
out.print(attrName + "=");
final String attrValue = attribute.getValue();
if (AttributeType.HTML.equals(attribute.getType())) {
out.print("<" + attrValue + ">");
} else {
out.print("\"" + escapeDoubleQuotes(attrValue) + "\"");
}
out.print(" ");
}
private static String escapeDoubleQuotes(String labelName)
{
return labelName.replaceAll("\"", Matcher.quoteReplacement("\\\""));
}
/**
* Return a valid vertex ID (with respect to the .dot language definition as described in
* http://www.graphviz.org/doc/info/lang.html
*
*
* Quoted from above mentioned source: An ID is valid if it meets one of the following criteria:
*
*
* - any string of alphabetic characters, underscores or digits, not beginning with a digit;
*
- a number [-]?(.[0-9]+ | [0-9]+(.[0-9]*)? );
*
- any double-quoted string ("...") possibly containing escaped quotes (\");
*
- an HTML string (<...>).
*
*
* @throws ExportException if the given vertexIDProvider didn't generate a valid
* vertex ID.
*/
private String getVertexID(V v)
{
String vertexId = validatedIds.get(v);
if (vertexId == null) {
/*
* use the associated id provider for an ID of the given vertex
*/
vertexId = getVertexId(v);
/*
* test if it is a valid ID
*/
if (!DOTUtils.isValidID(vertexId)) {
throw new ExportException(
"Generated id '" + vertexId + "'for vertex '" + v
+ "' is not valid with respect to the .dot language");
}
validatedIds.put(v, vertexId);
}
return vertexId;
}
}