CRUD operation using yFilesAPI

yFiles API is used do manipulation Graphml files, this sample program is doing CRUD operation .graphml formatted Files


package project1;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import java.util.HashMap;
import java.util.Map;

import y.base.Edge;
import y.base.Graph;
import y.base.Node;
import y.base.NodeCursor;
import y.base.NodeMap;

import y.io.GraphMLIOHandler;
import y.io.graphml.Future;
import y.io.graphml.GraphMLHandler;
import y.io.graphml.KeyScope;
import y.io.graphml.KeyType;


public class GraphMLCURD {
    public GraphMLCURD() {
        super();
    }

    public static void main(String[] args) throws Exception {
        GraphMLCURD graphmlCURD = new GraphMLCURD();
      graphmlCURD.createGraphML();
       graphmlCURD.readGraphML();
        graphmlCURD.deleteGraphMLContent(new Integer(3));

    }

    /**
     *method to create .graphml File using graph structure
     */
    public void createGraphML() throws Exception {
        //creating a empty graph
        Graph graph = new Graph();

        //creating nodes
        Node[] nodes = new Node[5];
        for (int i = 0; i < nodes.length; i++) {
            nodes[i] = graph.createNode();
        }

        //creating edges
        Edge[] edges = new Edge[4];
        for (int i = 0; i < edges.length; i++) {
            edges[i] = graph.createEdge(nodes[i], nodes[i + 1]);
        }

        //creating keys inform of NodeMaps
        NodeMap nodeMap = graph.createNodeMap();
        int nodeValue = 0;
        for (NodeCursor nc = graph.nodes(); nc.ok(); nc.next()) {
            nodeMap.setInt(nc.node(), nodeValue++);
        }

        //creating graphml handler from GraphMLIOHandler.graphml handler will be useful for reading/writing graph data
        GraphMLIOHandler ioh = new GraphMLIOHandler();
        GraphMLHandler graphMLHandler = ioh.getGraphMLHandler();
        //below is for attribute data provider
        graphMLHandler.addOutputDataProvider("mykey", nodeMap, KeyScope.NODE,
                                             KeyType.INT);

        //writing graph to .graphml file
        graphMLHandler.write(graph,
                             new FileOutputStream(new File("mygraph.graphml")));


    }

    public void updateGraphML() {
        //This funtionality is covered as part of delete
    }

    /**
     *method read .graphml and populate graph object
     */
    public Map readGraphML() throws Exception {
        //creating graphml handler from GraphMLIOHandler.graphml handler will be useful for reading/writing graph data
        GraphMLIOHandler ioh = new GraphMLIOHandler();
        GraphMLHandler graphMLHandler = ioh.getGraphMLHandler();

        //creating a empty graph, later which will be populated with .graphml data
        Graph graph = new Graph();

        //adding data accepator which will read attribute data
        Future future =
            graphMLHandler.addInputDataAcceptorFuture("mykey", KeyScope.ALL,
                                                      KeyType.INT);
        //reading graphml data and populating it to Graph object
        graphMLHandler.read(graph,
                            new FileInputStream(new File("mygraph.graphml")));
        System.out.println("Printing populated graph object ::: " + graph);

        //constructing graph and attribute data details
        Map map = new HashMap();
        map.put("GRAPH", graph);
        map.put("NODE_DATA", future);
        return map;

    }

    /**
     *method to delete and update .graphml file with provided data
     */
    public void deleteGraphMLContent(Integer nodeData) throws Exception {
        //load graph and future
        Map map = readGraphML();
        Graph graph = (Graph)map.get("GRAPH");
        Future future = (Future)map.get("NODE_DATA");

        GraphMLIOHandler ioh = new GraphMLIOHandler();
        GraphMLHandler graphMLHandler = ioh.getGraphMLHandler();
        graphMLHandler.addOutputDataProvider("mykey",
                                             (NodeMap)future.getValue(),
                                             KeyScope.NODE, KeyType.INT);
        for (NodeCursor nc = graph.nodes(); nc.ok(); nc.next()) {
            NodeMap nodeMap1 = (NodeMap)future.getValue();
            if (((Integer)nodeMap1.get(nc.node())).intValue() == nodeData) {
                graph.removeNode(nc.node());
            }

        }
        graphMLHandler.write(graph,
                             new FileOutputStream(new File("updatedmygraph.graphml")));

    }
}