Introduction to Neo4j (#1098)

* Nashorn

* Nashorn x2

* Nashorn added trailing newlines

* Cleanup

* Formatted script lines

* Change system outs to asserts

* Change Nashorn to be Junit tests

* Remove empty test

* Added Neo4j section

* Revert NashornTest

core-java/pom.xml

@@ -1,5 +1,5 @@
 <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">
+         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>com.baeldung</groupId>
     <artifactId>core-java</artifactId>
@@ -10,6 +10,44 @@
 
     <dependencies>
 
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j</artifactId>
+            <version>3.1.0</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j.driver</groupId>
+            <artifactId>neo4j-java-driver</artifactId>
+            <version>1.1.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j-jdbc-driver</artifactId>
+            <version>3.0.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j-ogm-core</artifactId>
+            <version>2.1.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j-ogm-embedded-driver</artifactId>
+            <version>2.1.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.google.inject</groupId>
+            <artifactId>guice</artifactId>
+            <version>4.1.0</version>
+            <classifier>no_aop</classifier>
+            <scope>test</scope>
+        </dependency>
+
         <!-- utils -->
         <dependency>
             <groupId>net.sourceforge.collections</groupId>
@@ -63,7 +101,6 @@
             <artifactId>grep4j</artifactId>
             <version>${grep4j.version}</version>
         </dependency>
-        
         <!-- web -->
 
         <!-- marshalling -->
@@ -263,7 +300,8 @@
                         <configuration>
                             <shadedArtifactAttached>true</shadedArtifactAttached>
                             <transformers>
-                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                <transformer
+                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                     <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
                                 </transformer>
                             </transformers>

core-java/src/main/java/com/baeldung/graph/Car.java

@@ -0,0 +1,50 @@
+package com.baeldung.graph;
+
+import org.neo4j.ogm.annotation.GraphId;
+import org.neo4j.ogm.annotation.NodeEntity;
+import org.neo4j.ogm.annotation.Relationship;
+
+/**
+ * @author Danil Kornishev (danil.kornishev@mastercard.com)
+ */
+@NodeEntity
+public class Car {
+    @GraphId
+    private Long id;
+
+    private String make;
+
+    @Relationship(direction = "INCOMING")
+    private Company company;
+
+    public Car(String make, String model) {
+        this.make = make;
+        this.model = model;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getMake() {
+        return make;
+    }
+
+    public void setMake(String make) {
+        this.make = make;
+    }
+
+    public String getModel() {
+        return model;
+    }
+
+    public void setModel(String model) {
+        this.model = model;
+    }
+
+    private String model;
+}

core-java/src/main/java/com/baeldung/graph/Company.java

@@ -0,0 +1,45 @@
+package com.baeldung.graph;
+
+import org.neo4j.ogm.annotation.NodeEntity;
+import org.neo4j.ogm.annotation.Relationship;
+
+/**
+ * @author Danil Kornishev (danil.kornishev@mastercard.com)
+ */
+@NodeEntity
+public class Company {
+    private Long id;
+
+    private String name;
+
+    @Relationship(type="owns")
+    private Car car;
+
+    public Company(String name) {
+        this.name = name;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Car getCar() {
+        return car;
+    }
+
+    public void setCar(Car car) {
+        this.car = car;
+    }
+}

core-java/src/test/java/com/baeldung/graph/Neo4JServerTest.java

@@ -0,0 +1,60 @@
+package com.baeldung.graph;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.Statement;
+
+import org.junit.Ignore;
+import org.junit.Test;
+import org.neo4j.driver.v1.AuthTokens;
+import org.neo4j.driver.v1.Driver;
+import org.neo4j.driver.v1.GraphDatabase;
+import org.neo4j.driver.v1.Session;
+import org.neo4j.driver.v1.StatementResult;
+import org.testng.Assert;
+
+@Ignore
+public class Neo4JServerTest {
+
+    @Test
+    public void standAloneDriver() {
+        Driver driver = GraphDatabase.driver("bolt://localhost:7687", AuthTokens.basic("neo4j", "12345"));
+        Session session = driver.session();
+
+        session.run("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        StatementResult result = session.run("MATCH (company:Company)-[:owns]-> (car:Car)" +
+                "WHERE car.make='tesla' and car.model='modelX'" +
+                "RETURN company.name");
+
+        Assert.assertTrue(result.hasNext());
+        Assert.assertEquals(result.next().get("company.name").asString(), "Baeldung");
+
+        session.close();
+        driver.close();
+    }
+    
+    @Test
+    public void standAloneJdbc() throws Exception {
+        Connection con = DriverManager.getConnection("jdbc:neo4j:bolt://localhost/?user=neo4j,password=12345,scheme=basic");
+
+        // Querying
+        try (Statement stmt = con.createStatement()) {
+            stmt.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                    "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                    "RETURN baeldung, tesla");
+
+            ResultSet rs = stmt.executeQuery("MATCH (company:Company)-[:owns]-> (car:Car)" +
+                    "WHERE car.make='tesla' and car.model='modelX'" +
+                    "RETURN company.name");
+
+            while (rs.next()) {
+                Assert.assertEquals(rs.getString("company.name"), "Baeldung");
+            }
+        }
+        con.close();
+    }
+}

core-java/src/test/java/com/baeldung/graph/Neo4jOgmTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.graph;
+
+import org.junit.Test;
+import org.neo4j.ogm.config.Configuration;
+import org.neo4j.ogm.model.Result;
+import org.neo4j.ogm.session.Session;
+import org.neo4j.ogm.session.SessionFactory;
+import org.testng.Assert;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author Danil Kornishev (danil.kornishev@mastercard.com)
+ */
+public class Neo4jOgmTest {
+
+    @Test
+    public void testOgm() {
+        Configuration conf = new Configuration();
+        conf.driverConfiguration().setDriverClassName("org.neo4j.ogm.drivers.embedded.driver.EmbeddedDriver");
+
+        SessionFactory factory = new SessionFactory(conf, "com.baeldung.graph");
+        Session session = factory.openSession();
+
+        Car tesla = new Car("tesla", "modelS");
+        Company baeldung = new Company("baeldung");
+
+        baeldung.setCar(tesla);
+
+        session.save(baeldung);
+
+        Map<String, String> params = new HashMap<>();
+        params.put("make", "tesla");
+        Result result = session.query("MATCH (car:Car) <-[:owns]- (company:Company)" +
+                " WHERE car.make=$make" +
+                " RETURN company", params);
+
+        Map<String, Object> firstResult = result.iterator().next();
+
+        Assert.assertEquals(firstResult.size(), 1);
+
+        Company actual = (Company) firstResult.get("company");
+        Assert.assertEquals(actual.getName(), baeldung.getName());
+    }
+}

core-java/src/test/java/com/baeldung/graph/Neo4jTest.java

@@ -0,0 +1,167 @@
+package com.baeldung.graph;
+
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.neo4j.graphdb.GraphDatabaseService;
+import org.neo4j.graphdb.Label;
+import org.neo4j.graphdb.Node;
+import org.neo4j.graphdb.NotFoundException;
+import org.neo4j.graphdb.RelationshipType;
+import org.neo4j.graphdb.Result;
+import org.neo4j.graphdb.factory.GraphDatabaseFactory;
+import org.testng.Assert;
+
+public class Neo4jTest {
+
+    private static GraphDatabaseService graphDb;
+
+    @Before
+    public void setUp() {
+        GraphDatabaseFactory graphDbFactory = new GraphDatabaseFactory();
+        graphDb = graphDbFactory.newEmbeddedDatabase(new File("data/cars"));
+    }
+
+    @After
+    public void tearDown() {
+        graphDb.shutdown();
+    }
+
+    @Test
+    public void testPersonCar() {
+        graphDb.beginTx();
+        Node car = graphDb.createNode(Label.label("Car"));
+        car.setProperty("make", "tesla");
+        car.setProperty("model", "model3");
+
+        Node owner = graphDb.createNode(Label.label("Person"));
+        owner.setProperty("firstName", "baeldung");
+        owner.setProperty("lastName", "baeldung");
+
+        owner.createRelationshipTo(car, RelationshipType.withName("owner"));
+
+        Result result = graphDb.execute("MATCH (c:Car) <-[owner]- (p:Person) " +
+                "WHERE c.make = 'tesla'" +
+                "RETURN p.firstName, p.lastName");
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertEquals("baeldung", firstResult.get("p.firstName"));
+    }
+
+    @Test
+    public void testCreateNode() {
+
+        graphDb.beginTx();
+
+        Result result = graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"})" +
+                "RETURN baeldung");
+
+        Map<String, Object> firstResult = result.next();
+        Node firstNode = (Node) firstResult.get("baeldung");
+        Assert.assertEquals(firstNode.getProperty("name"), "Baeldung");
+    }
+
+    @Test
+    public void testCreateNodeAndLink() {
+        graphDb.beginTx();
+
+        Result result = graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertTrue(firstResult.containsKey("baeldung"));
+        Assert.assertTrue(firstResult.containsKey("tesla"));
+    }
+
+    @Test
+    public void testFindAndReturn() {
+        graphDb.beginTx();
+
+        graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        Result result = graphDb.execute("MATCH (company:Company)-[:owns]-> (car:Car)" +
+                "WHERE car.make='tesla' and car.model='modelX'" +
+                "RETURN company.name");
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertEquals(firstResult.get("company.name"), "Baeldung");
+    }
+
+    @Test
+    public void testUpdate() {
+        graphDb.beginTx();
+
+        graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        Result result = graphDb.execute("MATCH (car:Car)" +
+                "WHERE car.make='tesla'" +
+                " SET car.milage=120" +
+                " SET car :Car:Electro" +
+                " SET car.model=NULL" +
+                " RETURN car");
+
+        Map<String, Object> firstResult = result.next();
+        Node car = (Node) firstResult.get("car");
+
+        Assert.assertEquals(car.getProperty("milage"), 120L);
+        Assert.assertEquals(car.getLabels(), Arrays.asList(Label.label("Car"), Label.label("Electro")));
+
+        try {
+            car.getProperty("model");
+            Assert.fail();
+        } catch (NotFoundException e) {
+            // expected
+        }
+    }
+
+    @Test
+    public void testDelete() {
+        graphDb.beginTx();
+
+        graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        graphDb.execute("MATCH (company:Company)" +
+                " WHERE company.name='Baeldung'" +
+                " DELETE company");
+
+        Result result = graphDb.execute("MATCH (company:Company)" +
+                " WHERE company.name='Baeldung'" +
+                " RETURN company");
+
+        Assert.assertFalse(result.hasNext());
+    }
+
+    @Test
+    public void testBindings() {
+        graphDb.beginTx();
+
+        Map<String, Object> params = new HashMap<>();
+        params.put("name", "baeldung");
+        params.put("make", "tesla");
+        params.put("model", "modelS");
+
+        Result result = graphDb.execute("CREATE (baeldung:Company {name:$name}) " +
+                "-[:owns]-> (tesla:Car {make: $make, model: $model})" +
+                "RETURN baeldung, tesla", params);
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertTrue(firstResult.containsKey("baeldung"));
+        Assert.assertTrue(firstResult.containsKey("tesla"));
+
+        Node car = (Node) firstResult.get("tesla");
+        Assert.assertEquals(car.getProperty("model"), "modelS");
+    }
+}