insert object if it not exist in neo4j db - neo4j

Question

I've got an object that looks like this
import lombok.Data;
import org.neo4j.ogm.annotation.GraphId;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.annotation.Relationship;
import java.util.HashSet;
import java.util.Set;
#Data
#NodeEntity
public class GPlayer {
#GraphId
private Long id;
#Relationship(type = "comrade", direction = Relationship.UNDIRECTED)
private Set<GPlayer> comrades;
// #Indexed(unique = true) doesn't work in v4
private String name;
/**
* Adds new comrade.
*
* #param comrade comrade
*/
public void acquainted(GPlayer comrade) {
if (null == comrades) {
comrades = new HashSet<>();
} else {
if (comrades.contains(comrade)) {
return;
}
}
comrades.add(comrade);
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
if (!super.equals(o)) return false;
GPlayer gPlayer = (GPlayer) o;
if (!id.equals(gPlayer.id)) return false;
return name.equals(gPlayer.name);
}
#Override
public int hashCode() {
int result = super.hashCode();
result = 31 * result + id.hashCode();
result = 31 * result + name.hashCode();
return result;
}
#Override
public String toString() {
return "GPlayer{" +
"id=" + id +
", comrades=" + comrades +
", name='" + name + '\'' +
'}';
}
}
I want to store it in Neo4j with unique name. So when I insert GPlayer - if the object with such name doesn't exist I don't want to insert it.
I have repository that looks like this
public interface GraphPlayerRepository extends GraphRepository<GPlayer> {
List<GPlayer> findAll();
GPlayer findByName(String name);
}
To insert I do like this
private Long createPlayer(String playerName, String comrade, GraphPlayerRepository gRepo) {
GPlayer gPlayer = gRepo.findByName(playerName);
if (null == gPlayer) {
gPlayer = new GPlayer();
gPlayer.setName(playerName);
if (null != comrade) {
gPlayer.acquainted(gRepo.findByName(comrade));
}
gRepo.save(gPlayer);
LOGGER.info("Created new GRAPH player: {}", gPlayer);
} else {
gPlayer.acquainted(gRepo.findByName(comrade));
gRepo.save(gPlayer);
LOGGER.info("Updated player: {}", gPlayer);
}
return gPlayer.getId();
}
But it looks rather verbose. Is there a way to make it simpler?

Answer 1

You could use the name as the id of the entity
#Index(unique=true, primary=true)
private String name;
Then no need to declare the findByName method, just use Neo4jRepository
public interface GraphPlayerRepository extends Neo4jRepository<GPlayer, String> {
...
}
and use repository.findOne(name) to get players from the name.
That said, the implementation of hashCode and Equals is incorrect : it is strongly advised not to use the Long id in these. See here.
Otherwise, not related to SDN, but improvements could include :
use lombok to generate hashcode and equals
initialize the hashSet at the field level
You could also migrate to SDN 5 and make use of Optional return types to avoid the if/else nullity check blocks.