Fragments from Neo4j demo

fragment-01-db-initialization.java

    protected final static String DBPATH = "./localdb";
    protected GraphDatabaseService db = null;
…
     protected void startup()
    {
        // instantiate the database
        db = new GraphDatabaseFactory().newEmbeddedDatabase(DBPATH);
…

fragment-02-db.shutdown.java

…
    db.shutdown();
…

fragment-03-shutdown-hook.java

        // register shutdown hook
        Runtime.getRuntime().addShutdownHook(new Thread()
        {
            @Override
            public void run()
            {
                db.shutdown();
            }
        });

fragment-04-transaction.java

        try (final Transaction t = db.beginTx())
        {
….
	t.success();
	}

fragment-05-hello-world.java

		… 
            Node n1 = db.createNode();
            n1.setProperty("text", "Hello");
            Node n2 = db.createNode();
            n2.setProperty("text", "World");
            Relationship r = n1.createRelationshipTo(n2, DemoRelationship.linked_to);
            r.setProperty("text", "to all the");
		… 

fragment-06-relationship.java

… 
public enum DemoRelationship implements RelationshipType
{
    linked_to
}
… 

fragment-07-randomperson.java

… 
    private Node randomPerson(String family, int generation)
    {
        Node person = db.createNode(personLabel);
        String sex = Math.random()>.5?"M":"F";
        String name;
        if("F".equals(sex))
        {
            name = fNames[(int)(Math.random()*fNames.length)];
        }
        else
        {
            name = mNames[(int)(Math.random()*mNames.length)];
        }
        person.setProperty("sex", sex);
        person.setProperty("name", name);
        person.setProperty("family", family);
        person.setProperty("generation", generation);
        return person;
    }
… 

fragment-08-initial-fill.java

… 
            ResourceIterable<Node> gotRoot = db.findNodesByLabelAndProperty(rootLabel, "type", "root");
            if(gotRoot==null || !gotRoot.iterator().hasNext())
            {
                Node root = db.createNode(rootLabel);
                root.setProperty("type", "root");
                // initial database fill
                for(int j=0;j<INITIAL_FILL;j++)
                {
                    Node person = randomPerson();
                    person.createRelationshipTo(root, PersonRelationships.initial_setup);
                }
                t.success();
                result = root;
            }
            else
            {
                result = gotRoot.iterator().next();
            }
… 

fragment-09-generation-query.java

… 
    private static final String GENERATION_QUERY = "match (n:person) "
                                                   + "where not (n-[:married_with]->(:person)) "
                                                   + "and n.sex={sex} "
                                                   + "and rand()>{pick} "
                                                   + "and n.generation={generation} "
                                                   + "return n;";
… 

fragment-10-generation.java

… 
                // mate some of same level nodes            
                Node male = (Node) males.columnAs("n").next();
                Node female = (Node) females.columnAs("n").next();
                male.createRelationshipTo(female, PersonRelationships.married_with);
                // add random children to some random mated nodes
                if(Math.random()>BIRTH_RATIO)
                {
                    final double children = Math.random()*MAX_CHLDREN;
                    for(int j=1;j<children;j++)
                    {
                        Node c = randomPerson((String) male.getProperty("family"), generation + 1);
                        c.createRelationshipTo(male, PersonRelationships.child_of);
                        c.createRelationshipTo(female, PersonRelationships.child_of);
                    }
                }
…

more at http://massimomusante.blogspot.it/2014/08/neo4j-and-java-demos-with-embedded.html