Code sample from 'Why proponents of marriage equality should love graph databases, Part 2' http://bit.ly/dccCPj

Neo4J Gay Marriage Example

// Creative Commons Attribution-Share Alike 3.0 United States License
// http://creativecommons.org/licenses/by-sa/3.0/us/
// From blog post: http://bit.ly/dccCPj
package net.susanpotter.inclusivemarriage;

import java.text.SimpleDateFormat;
import java.text.ParseException;
import java.util.Date;

import org.neo4j.graphdb.*;
import org.neo4j.kernel.EmbeddedGraphDatabase;

public class NeoBase {
    public enum IMRelationshipTypes implements RelationshipType {
        MARRIED, KNOWS, THINKS
    }

    public static void main(String[] args) {
        GraphDatabaseService graphDb = new EmbeddedGraphDatabase("var/base");
        Transaction tx = graphDb.beginTx();
        try {
            Node harry = toPersonNode(graphDb, "Harry");
            Node mary = toPersonNode(graphDb, "Mary");
            Node teresa = toPersonNode(graphDb, "Teresa");
            Node tony = toPersonNode(graphDb, "Tony");
            Node fredPhelps = toPersonNode(graphDb, "Fred Phelps");
            Node bigotedOpinion = toOpinionNode(graphDb, "Homosexuals are going to hell!");

            Relationship t2mMarriage = toMarriage(graphDb, teresa, mary, "2008-08-08", null);
            Relationship m2hMarriage = toMarriage(graphDb, mary, harry, "2005-05-03", "2010-01-23");
            Relationship hate = fredPhelps.createRelationshipTo(bigotedOpinion, IMRelationshipTypes.THINKS);
            Relationship t2hFriendship = toFriendship(graphDb, tony, harry, "1999-12-31", null);

            // now we can do some queries to demonstrate how graph databases can help with modeling gay and polyamorous relationships
            Traverser marysPartners = mary.traverse(
                Traverser.Order.BREADTH_FIRST,
                StopEvaluator.DEPTH_ONE,
                ReturnableEvaluator.ALL_BUT_START_NODE,
                IMRelationshipTypes.MARRIED,
                Direction.BOTH
            );

            for(Node partner : marysPartners) {
                System.out.println("Mary is married to " + partner.getProperty("name"));
            }

            Traverser tonysFriends = tony.traverse(
                Traverser.Order.BREADTH_FIRST,
                StopEvaluator.DEPTH_ONE,
                ReturnableEvaluator.ALL_BUT_START_NODE,
                IMRelationshipTypes.KNOWS,
                Direction.BOTH
            );

            for (Node friend : tonysFriends) {
                System.out.println("Tony is friends with " + friend.getProperty("name"));
            }

            Traverser fredPhelpsOpinions = fredPhelps.traverse(
                Traverser.Order.BREADTH_FIRST,
                StopEvaluator.DEPTH_ONE,
                ReturnableEvaluator.ALL_BUT_START_NODE,
                IMRelationshipTypes.THINKS,
                Direction.BOTH
            );

            for (Node opinion : fredPhelpsOpinions) {
                System.out.println("Fred Phelps thinks, \"" + opinion.getProperty("content") + "\"");
            }

            tx.success();

        } finally {
            tx.finish();
            graphDb.shutdown();
        }
    }

    private static Relationship toMarriage(GraphDatabaseService gdb, Node firstPartner, Node secondPartner, String createdAt, String expiredAt) {
        Relationship rel = firstPartner.createRelationshipTo(secondPartner, IMRelationshipTypes.MARRIED);
        if (null != createdAt) { rel.setProperty("createdAt", createdAt); }
        if (null != expiredAt) { rel.setProperty("expiredAt", expiredAt); }
        return rel;
    }
    private static Relationship toFriendship(GraphDatabaseService gdb, Node firstFriend, Node secondFriend, String createdAt, String expiredAt) {
        Relationship rel = firstFriend.createRelationshipTo(secondFriend, IMRelationshipTypes.KNOWS);
        if (null != createdAt) { rel.setProperty("createdAt", createdAt); }
        if (null != expiredAt) { rel.setProperty("expiredAt", expiredAt); }
        return rel;
    }

    private static Node toOpinionNode(GraphDatabaseService gdb, String content) {
        Node opinion = gdb.createNode();
        opinion.setProperty("content", content);
        return opinion;
    }

    private static Node toPersonNode(GraphDatabaseService gdb, String name) {
        Node person = gdb.createNode();
        person.setProperty("name", name);
        return person;
    }
}