jGrapht using groovy example

jgrapht_demo.groovy

@Grab('org.jgrapht:jgrapht-core:1.3.1')

import org.jgrapht.*
import org.jgrapht.graph.*
import org.jgrapht.io.*
import org.jgrapht.traverse.*

class Main {

    static void main(args){
        Graph<String, DefaultEdge> stringGraph = createStringGraph()

        // note undirected edges are printed as: {<v1>,<v2>}
        println("-- toString output")
        println(stringGraph.toString())
        println()

        // create a graph based on URI objects
        Graph<URI, DefaultEdge> hrefGraph = createHrefGraph()

        // find the vertex corresponding to www.jgrapht.org
//        URI start = hrefGraph.vertexSet().stream().filter(uri -> uri.getHost().equals("www.jgrapht.org")).findAny().get()
        URI start = hrefGraph.vertexSet().find{ uri -> uri.getHost() == "www.jgrapht.org"}

        // perform a graph traversal starting from that vertex
        println("-- traverseHrefGraph output")
        traverseHrefGraph(hrefGraph, start)
        println()

        println("-- renderHrefGraph output")
        renderHrefGraph(hrefGraph)
        println('done.')
    }

    static Graph<URI, DefaultEdge> createHrefGraph(){

        Graph<URI, DefaultEdge> g = new DefaultDirectedGraph<>(DefaultEdge)

        URI google = new URI("http://www.google.com")
        URI wikipedia = new URI("http://www.wikipedia.org")
        URI jgrapht = new URI("http://www.jgrapht.org")

        // add the vertices
        g.addVertex(google)
        g.addVertex(wikipedia)
        g.addVertex(jgrapht)

        // add edges to create linking structure
        g.addEdge(jgrapht, wikipedia)
        g.addEdge(google, jgrapht)
        g.addEdge(google, wikipedia)
        g.addEdge(wikipedia, google)

        return g
    }
    
    
    static void traverseHrefGraph(Graph<URI, DefaultEdge> hrefGraph, URI start)
    {
        new DepthFirstIterator<>(hrefGraph, start).each { uri ->
            println(uri)
        }
    }
    
    
    static void renderHrefGraph(Graph<URI, DefaultEdge> hrefGraph)
    {

        // use helper classes to define how vertices should be rendered,
        // adhering to the DOT language restrictions
        def vertexIdProvider = { it.host.replace('.', '_') }
        def vertexLabelProvider = { it.toString() }
        
        // Error cannot find class GraphExporter
        /*GraphExporter<URI, DefaultEdge> exporter =
            new DOTExporter<>(vertexIdProvider, vertexLabelProvider, null)
        Writer writer = new StringWriter()
        exporter.exportGraph(hrefGraph, writer)
        println(writer.toString())*/
    }
    
    static Graph<String, DefaultEdge> createStringGraph()
    {
        Graph<String, DefaultEdge> g = new SimpleGraph<>(DefaultEdge)

        String v1 = "v1"
        String v2 = "v2"
        String v3 = "v3"
        String v4 = "v4"

        // add the vertices
        g.addVertex(v1)
        g.addVertex(v2)
        g.addVertex(v3)
        g.addVertex(v4)

        // add edges to create a circuit
        g.addEdge(v1, v2)
        g.addEdge(v2, v3)
        g.addEdge(v3, v4)
        g.addEdge(v4, v1)

        return g
    }
    
}