I'm developing a Spring web application whose persistence layer consists in Spring Roo generated JPA entities, with Hibernate as persistence provider and MySql as underlying DB.
Among my entities I have a class Detection with a tstamp java.util.Date field generated in Roo as follows:
entity jpa --class ~.data.Detection
...
field date --fieldName tstamp --type java.util.Date
...
finder add findDetectionsByTstampBetween
(the finder method was of course chosen after executing finder list)
In my controller code, at a point I invoke:
List<Detection> detections = Detection.findDetectionsByTstampBetween(from, to).getResultList();
Where from and to are two valid java.util.Date(s). When testing sample data though (after ensuring that for a given choice of from, to the returned list shouldn't be empty), I got an empty list and investigated the reasons.
I found in tomcat logs that Hibernate was generating the following SQL:
Hibernate: select detection0_.id as id1_3_, ...etc..., detection0_.tstamp as tstamp4_3_ from detection detection0_ where detection0_.tstamp>=?
I would expect the where clause should contain a trailing "AND detection0_.tstamp<=?", checking the other date range limit. I took a look at the generated Detection.findDetectionsByTstampBetween(Date minTstamp, Date maxTstamp) method in Detection_Roo_Finder.aj and actually the "AND" is present in the invocation to createQuery.
public static TypedQuery<Detection> Detection.findDetectionsByTstampBetween(Date minTstamp, Date maxTstamp) {
if (minTstamp == null) throw new IllegalArgumentException("The minTstamp argument is required");
if (maxTstamp == null) throw new IllegalArgumentException("The maxTstamp argument is required");
EntityManager em = Detection.entityManager();
TypedQuery<Detection> q = em.createQuery("SELECT o FROM Detection AS o WHERE o.tstamp BETWEEN :minTstamp AND :maxTstamp", Detection.class);
q.setParameter("minTstamp", minTstamp);
q.setParameter("maxTstamp", maxTstamp);
return q;
}
Any idea what could cause the problem?
I've finally found the solution to the riddle and, as it turned out, the issue had nothing to do with JPA.
The problem was that the call to the persistence layer was inserted inside a Rest service controller with the following mapping:
#ResponseBody
#RequestMapping(value="/detections", method=RequestMethod.GET, params="from, to" )
public Object getDetectionsInRange(
#RequestParam(required=true) #DateTimeFormat(pattern="yyyy-MM-dd HH:mm") final Date from,
#RequestParam(required=true) #DateTimeFormat(pattern="yyyy-MM-dd HH:mm") final Date to
)
{
...
List<Detection> detections = Detection.findDetectionsByTstampBetween(from, to).getResultList();
...
}
The error was in the definition of the params= argument in #RequestMapping, the correct format being as follows:
#RequestMapping(value="/detections", method=RequestMethod.GET, params={"from", "to"} )
This error caused another version of the controller method for /detections. In this second version I called a different finder method, which appeared to generate the wrong SQL in Hibernate.
#ResponseBody
#RequestMapping(value="/detections", method=RequestMethod.GET )
public Object getDetections(
#RequestParam(required=false, defaultValue="0") int days,
#RequestParam(required=false, defaultValue="0") int hours,
#RequestParam(required=false, defaultValue="0") int minutes
)
{
...
List<Detection> detections = Detection.findDetectionsByTstampGreaterThanEquals( ... ).getResultList();
...
}
Related
I am trying to migrate to neo4j 6. Whats the equivalent of this method in neo4j6?
The Result here contains: {ref=Employee.... etc, so the actual Java objects.
//org.neo4j.ogm.session.Session is autowired
#GetMapping("/companies/{companyId}/refs")
public Result getCompanyRefs(#PathVariable final String companyId)
{
String query = "MATCH (company:Company)-[ref]-(refObj) where company.id=\"" + companyId + "\" RETURN company,ref,refObj";
return this.session.query(query, Collections.emptyMap());
}
I tried with the new neo4j driver like so:
//org.neo4j.driver.Driver is autowired
#GetMapping("/persons/{personId}/refs")
public Result getPersonRefs(#PathVariable final String personId)
{
String query = "MATCH (person:Person)-[ref]-(refObj) where person.id=\"" + personId + "\" RETURN person,ref,refObj";
return this.driver.session().run(query, Collections.emptyMap());
}
but this gives a Result which is not convertable to my #Node (entity) classes. The previous version gave a Result which contained the actual java objects(mapped to classes).
the result here is:Record<{person: node<7>, ref: relationship<8>, refObj: node<0>}>
Basically the main thing is: i need the nodes mapped to java objects. But i need them via a cypher query, because i need to do some things on the (Result) Nodes before deleting the relationships between them.
so it turns out it does give back the things i need.
Result result = this.getPersonRefs(id);
result.list().forEach((entry) -> {
The problem was that for example neither entry.get("refObj").asObject(), nor asNode() actually gave back what i thought it was supposed to give back.
The Solution:
entry.get("refObj").asMap()
this gives back the actual properties of the object. Then you just need to convert it to MyClass.class with an ObjectMapper.
I am developing Spring Boot app to connect to Cassandra using Spring Data for Cassandra v1.5.10.Release.
I cannot find any reference that shows how to retrieve max(col) from Cassandra table using CassandraOperations and QueryBuilder. I tried below but it returns -
Undefined column name "max(id)"
public class CassandraTest{
#Autowired
private CassandraOperations cassandraTemplate;
public void execute() {
Select sel = QueryBuilder.select("max(id)").from("table").;
Integer maxId= cassandraTemplate.queryForObject(sel, Integer.class);
System.out.println("maxid ===> " + maxId);
}
}
After going through reference doc, I found out another way of doing it -old fashioned way without using QueryBuilder.
String selectQuery = "select max(id) as maxId from table";
Integer maxId= csOps.selectOne(selectQuery, Integer.class);
System.out.println("maxid ===> " + maxId);
I still want to know if it is possible with QueryBuilder. Interestingly, datastax driver Select api supports max function.
public Select.SelectionOrAlias max(Object column)
Description copied from class: Select.Selection
Creates a max(x) built-in function call.
Overrides:
max in class Select.Selection
Returns:
the function call.
This should work (although not tested):
Select sel = QueryBuilder.select().max(column("id")).from("table").;
So, I've already done this using the standard Spring Data JPA interface which extends PagingAndSortingRepository in order to achieve pagination and sorting for a REST API. The thing is, now I want to achieve the very same thing but now using just vanilla JPA and so far so good I managed to get my API to paginate but the sorting doesn't work at all. Every time I try to set the parameter (from a pageable object using pageable.getSort()) it ends with a query error (either if I just send a string as parameter like "name" or just send the sort object, it shows errors).
Here's some code:
My repo implementation:
#Override
public List<Project> findByAll(Pageable pageable) {
Query query = em.createQuery("SELECT project FROM Project project ORDER BY :sort");
query.setParameter("sort", pageable.getSort());
query.setMaxResults(pageable.getPageSize());
query.setFirstResult(pageable.getPageSize() * pageable.getPageNumber());
return query.getResultList();
}
My service:
#Override
public Page<Project> findAll(Pageable pageable) {
objects = Lists.newArrayList(repository.findByAll(pageable));
PageImpl<Project> pages= new PageImpl<Project>(objects, pageable, repository.count());
return pages;
}
To be clear, I'm filling the Pageable object via URI and from the console I can say it's actually getting the data, so I assume the problem is with the repo.
Edit: This is the error I get when I replace the setParameter("sort", ...) for a hardcoded string aka query.setParameter("sort", "name"):
java.lang.NumberFormatException: For input string: "name"
And I think this method should stand for strings as well. If I use query.setParameter("sort", pageable.getSort()), the error is the same.
The order by cannot be set as a query parameter. Also, the Pageable.getSort().toString() likely won't return a string suitable for use in an order by clause as it will result in a String that represents the Order as property: ORDER, note the colon.
Here are some modifications that will work, assuming Java 8...
String order = StringUtils.collectionToCommaDelimitedString(
StreamSupport.stream(sort.spliterator(), false)
.map(o -> o.getProperty() + " " + o.getDirection())
.collect(Collectors.toList()));
Query query = em.createQuery(
String.format("SELECT project FROM Project project ORDER BY %s", order));
I'm using Spring Data Neo4j in my project and I'm having issues with naming conventions for repositories.
This is a simple class containing only one field and the getters/setters
#RelationshipEntity
public class ScoredRelationship
{
protected Float score;
}
and the class below extends it with other kind of fields
#RelationshipEntity(
type = RecommenderRelTypes.GOV_CONSUMER_TO_GOV_CONSUMER_SIMILARITY)
public class GovConsumerToGovConsumerSimilarity extends ScoredRelationship
{ // Other fields}
To access the relationship, I'm using the usual repository class
public interface GovConsumerToGovConsumerSimilarityRepository extends
GraphRepository<GovConsumerToGovConsumerSimilarity>
{
public Set<GovConsumerToGovConsumerSimilarity> findByScoreGreaterThan(Float value);
public Set<GovConsumerToGovConsumerSimilarity>
findByScoreGreaterThanOrderByScoreDesc(Float value);
public Set<GovConsumerToGovConsumerSimilarity>
findTopXByScoreGreaterThanOrderByScoreDesc(int limit, Float score);
}
This code compiles well. However, whenever I'm trying to use one of the methods, Spring return a series of exception or doesn't act as intended.
F.e. #findByScoreGreaterThan(0.3f) always returns an empty set. However, invoking a findAll() and printing all the scores it actually has a lot of objects with a score greater than 0.3.
In the second and third case, it always throws an exception saying
Caused by: Unknown identifier `score`.
at org.neo4j.cypher.internal.symbols.SymbolTable.evaluateType(SymbolTable.scala:60)
at org.neo4j.cypher.internal.commands.expressions.Identifier.evaluateType(Identifier.scala:51)
at org.neo4j.cypher.internal.commands.expressions.Expression.assertTypes(Expression.scala:53)
at org.neo4j.cypher.internal.pipes.SortPipe$$anonfun$assertTypes$1.apply(SortPipe.scala:34)
at org.neo4j.cypher.internal.pipes.SortPipe$$anonfun$assertTypes$1.apply(SortPipe.scala:33)
at scala.collection.LinearSeqOptimized$class.foreach(LinearSeqOptimized.scala:59)
at scala.collection.immutable.List.foreach(List.scala:45)
at org.neo4j.cypher.internal.pipes.SortPipe.assertTypes(SortPipe.scala:33)
at org.neo4j.cypher.internal.pipes.PipeWithSource.<init>(PipeWithSource.scala:27)
at org.neo4j.cypher.internal.pipes.SortPipe.<init>(SortPipe.scala:29)
at org.neo4j.cypher.internal.executionplan.builders.SortBuilder.apply(SortBuilder.scala:33)
at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl.prepareExecutionPlan(ExecutionPlanImpl.scala:49)
at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl.<init>(ExecutionPlanImpl.scala:33)
at org.neo4j.cypher.ExecutionEngine$$anonfun$prepare$1.apply(ExecutionEngine.scala:67)
at org.neo4j.cypher.ExecutionEngine$$anonfun$prepare$1.apply(ExecutionEngine.scala:67)
at org.neo4j.cypher.internal.LRUCache.getOrElseUpdate(LRUCache.scala:37)
at org.neo4j.cypher.ExecutionEngine.prepare(ExecutionEngine.scala:67)
at org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:59)
at org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:63)
at org.neo4j.cypher.javacompat.ExecutionEngine.execute(ExecutionEngine.java:79)
at org.springframework.data.neo4j.support.query.CypherQueryEngine.parseAndExecuteQuery(CypherQueryEngine.java:61)
How could be possible? I mean, the class obviously has the score field. Also, executing the simple #findByScoreGreaterThan(float value) doesn't throw any exception, but at the same the latter method always returns an empty set.
EDIT:
These are the queries used by Spring. Actually, they seems right
Executing cypher query: START `govConsumerToGovConsumerSimilarity`=node:__types__(className="it.cerict.recommender.persistence.neo4j.GovConsumerToGovConsumerSimilarity") WHERE `govConsumerToGovConsumerSimilarity`.`score`! > {0} RETURN `govConsumerToGovConsumerSimilarity` params {0=0.3}
Executing cypher query: START `govConsumerToGovConsumerSimilarity`=node:__types__(className="it.cerict.recommender.persistence.neo4j.GovConsumerToGovConsumerSimilarity") WHERE `govConsumerToGovConsumerSimilarity`.`score`! > {0} RETURN `govConsumerToGovConsumerSimilarity` ORDER BY score DESC params {0=0.3}
EDIT2: I've also tried to change the score type from Float to float with no further improvements.
This seems to be a bug related to Spring Data Neo4j. Looking to the query executed, it is clear that it searches for nodes, while it should search for relationships.
I changed the #findByScoreGreaterThanOrderByScoreDesc() method using the #Query annotation that specifies the following Cypher query
START `govConsumerToGovConsumerSimilarity`=rel:__rel_types__(className="it.cerict.recommender.persistence.neo4j.GovConsumerToGovConsumerSimilarity") WHERE `govConsumerToGovConsumerSimilarity`.`score`! > 0.3 RETURN `govConsumerToGovConsumerSimilarity` ORDER BY `govConsumerToGovConsumerSimilarity`.`score` DESC;
Short Description
How do I make findBy<Field>In work with IN when the array list input is null. e.g. ignore it. What would your DAO for this look like?
Longer description.
Imagine you have creating a search for users page.
in the application. You have various options to filter on.
created (date range always given)
Country (when null ignore and search all countries)
AgeRange
Job Title
etc...
Now say you want to search for all users in a given date range in a list of countries.
When searching for users I will always search for a date joined however if I have not selected a country I want it to search for all countries.
I am planning on adding several more filter options other than country. So I don't really want to create lots of findBy methods for each possible field combination.
DAO
#Repository
public interface UserDao extends JpaRepository<User, Long> {
public List<BeatRate> findByCreatedBetweenAndCountryIn(Date from, Date to, ArrayList<String> countryList );
}
Test
#Test
public void test() throws ParseException {
Date from = new SimpleDateFormat( "yyyy-MM-dd" ).parse( "2015-01-01" );
Date to = new SimpleDateFormat("yyyy-MM-dd").parse("2015-05-15");
//ArrayList<String> countryList = new ArrayList<String>();
//countryList.add("UK");
//countryList.add("Australia");
//countryList.add("Japan"); // works ok when I have a list
countryList = null; // I want it to search for all countries when this is null -- this errors and doesnt work..
List<BeatRate> beatRates = beatRateDao.findByCreatedBetweenAndRentalCountryIn(from, to, countryList);
Assert.assertTrue(beatRates.size()>0);
}
You can have two methods:
beatRateDao.findByCreatedBetweenAndRentalCountryIn(from, to, countryList);
and
beatRateDao.findByCreatedBetweenAndRental(from, to);
Then simply pick one based on countryList:
List<BeatRate> beatRates = (countryList != null && !countryList.isEmpty())
? beatRateDao.findByCreatedBetweenAndRentalCountryIn(from, to, countryList)
: beatRateDao.findByCreatedBetweenAndRental(from, to);
The IN clause requires a non-nullable and non empty argument list as otherwise the query will fail.
On PostgreSQL, if you try to run a query like this:
select *
from product
where quantity in ( )
you get the following error:
ERROR: syntax error at or near ")"
LINE 3: where quantity in ( )
^
********** Error **********
ERROR: syntax error at or near ")"
SQL state: 42601
Character: 45