Spring Data Neo4j

# Spring Data Neo4j - Examples

This document provides comprehensive, real-world examples of Spring Data Neo4j patterns and implementations.

## Table of Contents

1. [Complete Movie Database Example](#complete-movie-database-example)
2. [Social Network Example](#social-network-example)
3. [E-Commerce Product Catalog](#e-commerce-product-catalog)
4. [Custom Query Examples](#custom-query-examples)
5. [Reactive Neo4j Examples](#reactive-neo4j-examples)
6. [Testing Examples](#testing-examples)

## Complete Movie Database Example

### Entity Classes

```java
@Node("Movie")
public class Movie {
    
    @Id
    private final String imdbId;
    
    private final String title;
    
    @Property("tagline")
    private final String description;
    
    private final Integer releaseYear;
    
    private final List<String> genres;
    
    @Relationship(type = "ACTED_IN", direction = Direction.INCOMING)
    private List<ActedIn> actors;
    
    @Relationship(type = "DIRECTED", direction = Direction.INCOMING)
    private List<Person> directors;
    
    public Movie(String imdbId, String title, String description, 
                 Integer releaseYear, List<String> genres) {
        this.imdbId = imdbId;
        this.title = title;
        this.description = description;
        this.releaseYear = releaseYear;
        this.genres = genres;
        this.actors = new ArrayList<>();
        this.directors = new ArrayList<>();
    }
    
    // Getters
    public String getImdbId() { return imdbId; }
    public String getTitle() { return title; }
    public String getDescription() { return description; }
    public Integer getReleaseYear() { return releaseYear; }
    public List<String> getGenres() { return genres; }
    public List<ActedIn> getActors() { return actors; }
    public List<Person> getDirectors() { return directors; }
}

@Node("Person")
public class Person {
    
    @Id @GeneratedValue
    private Long id;
    
    private final String name;
    
    private final Integer birthYear;
    
    @Relationship(type = "ACTED_IN", direction = Direction.OUTGOING)
    private List<ActedIn> actedIn;
    
    @Relationship(type = "DIRECTED", direction = Direction.OUTGOING)
    private List<Movie> directed;
    
    public Person(String name, Integer birthYear) {
        this.name = name;
        this.birthYear = birthYear;
        this.actedIn = new ArrayList<>();
        this.directed = new ArrayList<>();
    }
    
    public Person withId(Long id) {
        if (this.id != null && this.id.equals(id)) {
            return this;
        }
        Person newPerson = new Person(this.name, this.birthYear);
        newPerson.id = id;
        return newPerson;
    }
    
    // Getters
    public Long getId() { return id; }
    public String getName() { return name; }
    public Integer getBirthYear() { return birthYear; }
    public List<ActedIn> getActedIn() { return actedIn; }
    public List<Movie> getDirected() { return directed; }
}

@RelationshipProperties
public class ActedIn {
    
    @Id @GeneratedValue
    private Long id;
    
    @TargetNode
    private final Movie movie;
    
    private final List<String> roles;
    
    private final Integer screenTime;  // in minutes
    
    public ActedIn(Movie movie, List<String> roles, Integer screenTime) {
        this.movie = movie;
        this.roles = roles;
        this.screenTime = screenTime;
    }
    
    // Getters
    public Long getId() { return id; }
    public Movie getMovie() { return movie; }
    public List<String> getRoles() { return roles; }
    public Integer getScreenTime() { return screenTime; }
}
```

### Repository Interfaces

```java
@Repository
public interface MovieRepository extends Neo4jRepository<Movie, String> {
    
    // Simple query derivation
    Optional<Movie> findByTitle(String title);
    
    List<Movie> findByReleaseYear(Integer year);
    
    List<Movie> findByReleaseYearBetween(Integer startYear, Integer endYear);
    
    List<Movie> find