JJUG CCC Spring 2018 demo code

Main.java

package demo;

import org.apache.tinkerpop.gremlin.driver.Client;
import org.apache.tinkerpop.gremlin.driver.Cluster;
import org.apache.tinkerpop.gremlin.driver.remote.DriverRemoteConnection;
import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal;
import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversalSource;
import org.apache.tinkerpop.gremlin.structure.Graph;
import org.apache.tinkerpop.gremlin.structure.util.empty.EmptyGraph;

import java.io.Console;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOError;
import java.util.Map;
import java.util.concurrent.ExecutionException;

import static org.apache.tinkerpop.gremlin.process.traversal.P.*;
import static org.apache.tinkerpop.gremlin.process.traversal.Order.decr;
import static org.apache.tinkerpop.gremlin.process.traversal.Scope.local;
import static org.apache.tinkerpop.gremlin.structure.Column.*;

public class Main {
    public static void main(String[] args) {
        // Tinkerpopサーバーへの接続
        Cluster cluster;
        try {
            cluster = Cluster.build(new File("remote-objects.yaml")).create();
        } catch (FileNotFoundException e) {
            throw new IOError(e);
        }

        // 方法1: Gremlinクエリを文字列で投げる
        Client client = cluster.connect();
        String gremlinQuery = "g.V().hasLabel('customer').sample(5).valueMap('customerId', 'name')";
        try {
            client.submit(gremlinQuery).all()
                  .thenAccept(rs -> rs.forEach(r -> {
                      Map<String, Object> data = (Map<String, Object>) r.getObject();
                      System.out.println("Customer ID: " + data.get("customerId") + ", Name: " + data.get("name"));
                  })).get();
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        } finally {
            client.close();
        }

        // 方法2: トラバーサルを直接実行
        Console cons;
        String customerId;
        if ((cons = System.console()) != null) {
            do {
                customerId = cons.readLine( "Customer ID? ");
            } while (customerId == null || customerId.isEmpty());
            System.out.println("Recommendation for " + customerId);

            Graph graph = EmptyGraph.instance();
            GraphTraversalSource g = graph.traversal().withRemote(DriverRemoteConnection.using(cluster, "g"));
            GraphTraversal t = g.V().has("customer", "customerId", customerId).as("customer").
                    out("ordered").out("contains").out("is").aggregate("products").
                    in("is").in("contains").in("ordered").where(neq("customer")).
                    out("ordered").out("contains").out("is").where(without("products")).
                    groupCount().order(local).by(values, decr).
                    select(keys).limit(local, 5).unfold().values("name");

            while (t.hasNext()) {
                System.out.println("> " + t.next());
            }

            try {
                g.close();
            } catch (Exception e) {
                // ignore
            }
        }

        cluster.close();
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>demo</groupId>
    <artifactId>tinkerpop-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.target>1.8</maven.compiler.target>
        <maven.compiler.source>1.8</maven.compiler.source>
        <tinkerpop.version>3.3.3</tinkerpop.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.tinkerpop</groupId>
            <artifactId>gremlin-driver</artifactId>
            <version>${tinkerpop.version}</version>
        </dependency>
    </dependencies>
</project>