I just started to use Neo4j with Spring Data and I'm not able to recover graph objects and convert them back to domain objects. I must say I have no previous experience in that kind of databases.
In that way, I'm using Spring Data repositories. For standard queries the repository code is auto-generated but I would like to define some custom methods, so I created my custom repository as explained here.
For example, I would like to be able to update a certain property value (currentValue property in this case) from a given edge between two certain nodes (searchByUserName is a previously defined index in my node entity which represents a user). I'm using the query method from the Neo4j template in my custom repository implementation as follows:
public class TwitterUserRepositoryImpl implements TwitterUserRepositoryCustom{
@Autowired
private Neo4jOperations neo4jTemplate;
public void updateRelationshipValueByUserName(
String userAUserName, String userBUserName, double value){
HashedMap params = new HashedMap();
params.put("userAUserName", userAUserName);
params.put("userBUserName", userBUserName);
params.put("value", value);
String query = "START x=node:searchByUserName(userName = {userAUserName}), " +
"y=node:searchByUserName(userName = {userBUserName})" +
" MATCH (x)-[r:FOLLOWS]->(y)" +
" SET r.currentValue = {value}" +
" RETURN r";
Result<Map<String, Object>> relationships = neo4jTemplate.query(query, params);
/* let's try to recover the relationship entity and do some more stuff */
}
The cypher query returns an "edge" between two users, where its relationship type is "FOLLOWS", simulating a Twitter users network. I have no idea how to convert this QueryResult object back to my RelationshipEntity object. Is that possible?
