Neo4j Repository - Writing query with a dynamic where clause - neo4j

Question

I am relatively new to Neo4j, and have a doubt regarding writing of dynamic queries in Neo4j with spring.
From what I have read, the queries are annotated with #Query parameter in an interface that extends the GraphRepository class, and the dynamic parameters are supplied as argument.
But my requirement is such that I have to dynamically generate the number of where clauses.
For example,
#Query("match n where n.__type__='com.connectme.domain.Person' and n.age > {0} return n.id)
public List<Object> getPeopleWithAge(Integer age);//
My query can also change wherein age can also be less than some value, in which case, the query can become :
#Query("match n where n.__type__='com.connectme.domain.Person' and n.age > {0} and n.age <{1} return n.id)
public List<Object> getPeopleWithAge(Integer age1, Integer age2);//
In similar way, many clauses around the age parameter can lead to variation in where clauses.
How can i dynamically handle this as currently I am only aware of this annotated way of executing queries.
Can I override and write my own custom queries ?

Answer 1

You can write your own custom query logic. First you create an extra interface containing the custom query method, so you get two repository interfaces
public interface YourRepository extends GraphRepository<SomeClass> implements YourRepositoryExtension{
//inferred queries, annotated queries
}
public interface YourRepositoryExtension {
EndResult<SomeClass> customQuery();
Iterable<SomeClass> customTraversal();
}
Then you make an implementation:
#Repository
public class YourRepositoryImpl implements YourRepositoryExtension {
#Autowired
private YourRepository yourRepository;
#Override
public EndResult<SomeClass> customQuery(){
//your query logic, using yourRepository to make cypher calls.
return yourRepository.query("START n.. etc.. RETURN n", <optional params>);
}
#Override
public Iterable<SomeClass> customTraversal(){
SomeClass startNode = yourRepository.findOne(123);
return yourRepository.findAllByTraversal(startNode, <some custom traversal>);
}
}