Considering an IT with Spring-Boot and JUnit that would test whether a collection returned from database contains all needed elements. What would be the best way to do that?
To illustrate, consider a JPA class/entity such as the following:
class Person {
Integer id;
String name;
String lastName;
Address address;
Account account;
}
Consider that ids of Person, Address and Account would be auto-generated, so I can't infer them.
Any help will be appreciated.
I identity 3 points :
1) Invoke the method under test that is save and flush the entity instance with the JpaRepository dedicated to your entity
2) Make sure that your integration test is reliable/valuable.
Here it matters to clear the first level cache of JPA (EntityManager.clear()) to test the actual retrieval from the database. The cache may hide some issue in your mapping that will be seen only as the object is actually found from the database.
3) Assert the expected behavior that is retrieve the saved entity from the DB and assert its state according to your expected.
For asserting fields of a object AssertJ could interest you.
It doesn't force you to override equals()/hashCode() and it is very simple and meaningful.
As you want to assert nested objects I advise to use a distinct assertThat() by object.
For example :
Person person = new Person()...;
// action
personRepository.saveAndFlush(person);
// clear the first level cache
em.clear();
// assertions
Optional<Person> optPerson = personRepository.findById(person.getId());
// JUnit
Assert.assertTrue(optPerson.isPresent());
// AssertJ
person = optPerson.get();
Assertions.assertThat(person)
.extracting(Person::getName, Person::getLastName)
.containsExactly("expected name", "expected last name");
Assertions.assertThat(person.getAccount())
.extracting(Account::getFoo, Account::getBar)
.containsExactly("expected foo", "expected bar");
Assertions.assertThat(person.getAddress())
.extracting(Address::getStreet, Address::getZip)
.containsExactly("expected street", "expected zip");
Related
developping a new Java Spring MVC microservice i have encountered a minor issue.
When i send a creation request for any entity, the id generated always follows the previous one.
My event entity id configuration
My user entity id configuration
For example, this is what i got from these 2 requests
User creation request (you can see the id value is 1)
Event creation request (you can see the id value is 2)
The created event Id is the last created user Id + 1 which i obviously do not want to happen.
I want separate Id values for each entity. I want to know what i am doing wrong.
Thank you
Your solution worker pretty well ;)
I finally used it and added #SequenceGenerator annotation to initialize the count at 0.
#SequenceGenerator(name = "seq", initialValue = 0)
public class ClassName {
#Id
#GeneratedValue(generator = "seq")
private Integer id;
}
Thank you very much Daniel, that's kind of you.
You are using #GeneratedValue without providing a strategy.
Therefore it uses the AUTO strategy by default which indicates that the persistence provider should pick an appropriate strategy for the particular database.
As both ID columns share the same name I assume that both entities share one and the same generator.
Which results in
Create event entity with ID = 1 as the generator started at one
Create user entity with ID = 1 + 1 as new generated value is requested
You should think about using different sequences for generating separate IDs for each entity.
Following uses a DB sequence to generate an ID
#Id
#GeneratedValue(generator = "my_entity_name_seq")
private long id;
If I would not specify a concrete generator in the annotation hibernate ,for example will, create a default sequence called hibernate_sequence which is then used for all entities which use #GeneratedValue without specifying a generator. This then leads to incremented values over all tables / entities.
I have a domain object in Spring which I am saving using JpaRepository.save method and using Sequence generator from Postgres to generate id automatically.
#SequenceGenerator(initialValue = 1, name = "device_metric_gen", sequenceName = "device_metric_seq")
public class DeviceMetric extends BaseTimeModel {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "device_metric_gen")
#Column(nullable = false, updatable = false)
private Long id;
///// extra fields
My use-case requires to do an upsert instead of normal save operation (which I am aware will update if the id is present). I want to update an existing row if a combination of three columns (assume a composite unique) is present or else create a new row.
This is something similar to this:
INSERT INTO customers (name, email)
VALUES
(
'Microsoft',
'hotline#microsoft.com'
)
ON CONFLICT (name)
DO
UPDATE
SET email = EXCLUDED.email || ';' || customers.email;
One way of achieving the same in Spring-data that I can think of is:
Write a custom save operation in the service layer that
Does a get for the three-column and if a row is present
Set the same id in current object and do a repository.save
If no row present, do a normal repository.save
Problem with the above approach is that every insert now does a select and then save which makes two database calls whereas the same can be achieved by postgres insert on conflict feature with just one db call.
Any pointers on how to implement this in Spring Data?
One way is to write a native query insert into values (all fields here). The object in question has around 25 fields so I am looking for an another better way to achieve the same.
As #JBNizet mentioned, you answered your own question by suggesting reading for the data and then updating if found and inserting otherwise. Here's how you could do it using spring data and Optional.
Define a findByField1AndField2AndField3 method on your DeviceMetricRepository.
public interface DeviceMetricRepository extends JpaRepository<DeviceMetric, UUID> {
Optional<DeviceMetric> findByField1AndField2AndField3(String field1, String field2, String field3);
}
Use the repository in a service method.
#RequiredArgsConstructor
public class DeviceMetricService {
private final DeviceMetricRepository repo;
DeviceMetric save(String email, String phoneNumber) {
DeviceMetric deviceMetric = repo.findByField1AndField2AndField3("field1", "field", "field3")
.orElse(new DeviceMetric()); // create new object in a way that makes sense for you
deviceMetric.setEmail(email);
deviceMetric.setPhoneNumber(phoneNumber);
return repo.save(deviceMetric);
}
}
A word of advice on observability:
You mentioned that this is a high throughput use case in your system. Regardless of the approach taken, consider instrumenting timers around this save. This way you can measure the initial performance against any tunings you make in an objective way. Look at this an experiment and be prepared to pivot to other solutions as needed. If you are always reading these three columns together, ensure they are indexed. With these things in place, you may find that reading to determine update/insert is acceptable.
I would recommend using a named query to fetch a row based on your candidate keys. If a row is present, update it, otherwise create a new row. Both of these operations can be done using the save method.
#NamedQuery(name="getCustomerByNameAndEmail", query="select a from Customers a where a.name = :name and a.email = :email");
You can also use the #UniqueColumns() annotation on the entity to make sure that these columns always maintain uniqueness when grouped together.
Optional<Customers> customer = customerRepo.getCustomersByNameAndEmail(name, email);
Implement the above method in your repository. All it will do it call the query and pass the name and email as parameters. Make sure to return an Optional.empty() if there is no row present.
Customers c;
if (customer.isPresent()) {
c = customer.get();
c.setEmail("newemail#gmail.com");
c.setPhone("9420420420");
customerRepo.save(c);
} else {
c = new Customer(0, "name", "email", "5451515478");
customerRepo.save(c);
}
Pass the ID as 0 and JPA will insert a new row with the ID generated according to the sequence generator.
Although I never recommend using a number as an ID, if possible use a randomly generated UUID for the primary key, it will qurantee uniqueness and avoid any unexpected behaviour that may come with sequence generators.
With spring JPA it's pretty simple to implement this with clean java code.
Using Spring Data JPA's method T getOne(ID id), you're not querying the DB itself but you are using a reference to the DB object (proxy). Therefore when updating/saving the entity you are performing a one time operation.
To be able to modify the object Spring provides the #Transactional annotation which is a method level annotation that declares that the method starts a transaction and closes it only when the method itself ends its runtime.
You'd have to:
Start a jpa transaction
get the Db reference through getOne
modify the DB reference
save it on the database
close the transaction
Not having much visibility of your actual code I'm gonna abstract it as much as possible:
#Transactional
public void saveOrUpdate(DeviceMetric metric) {
DeviceMetric deviceMetric = metricRepository.getOne(metric.getId());
//modify it
deviceMetric.setName("Hello World!");
metricRepository.save(metric);
}
The tricky part is to not think the getOne as a SELECT from the DB. The database never gets called until the 'save' method.
I have entity like:
#Id
#Column_name = "abc"
int pk;
#Column_name = "def"
int id;
And I have Repository as:
interface fetchDataRepository extends jpaRepository<className, int> {
#Query("Select S_Test.nextVal from dual");
Long generateId();
}
In above example S_Test is hardcoded sequence name.
But the problem is that I want to pass sequence name dynamically as follows:
Long generateId(#Param("sequenceName") String sequenceName)
and use inside #Query annotation as:
#Query("Select :sequenceName.nextVal from dual");
Is there anyway to do that? Any suggestion would be appreciated.
Edit: Isn't there possible to use #(#entityName). If yes, then please tell me how?
Unfortunately you can only substitute in things that you could do in JDBC anyway (so, pretty much just values in the INSERT and WHERE clauses). No dynamic table, column, schema names are supported.
There is one exception that may apply, and that is a limited subset of SpEL can be used. There is one variable available - #entityName. So, assuming that the #Entity annotation on your entity class is named identically to the sequence, you could use an #Query like so:
#Query("Select #{#entityName}.nextVal from dual");
Otherwise, since your query is simple and does not involve any object relational mapping, you would probably need to Create a custom repository implementation and inject a JdbcTemplate into it in order to run the query.
Else you could inject an EntityManager and try using the JPA Criteria API - but again you arent actualy trying to map a resultset to an entity so JdbcTemplate will be simpler.
Built-in queries to Spring Data Neo4j (SDN) return objects populated with depth 1 by default. This means that "children" (related nodes) of an object returned by a query are populated. That's good - there are actual objects on the end of references from objects returned by these queries.
Custom queries are depth 0 by default. This is a hassle.
In this answer, it is described how to get springboot neo4j to populate a related element to the target of a custom query - to achieve an extra one level of depth of results from the query.
I am having trouble with this method when the related elements are in a list:
#NodeEntity
public class BoardPosition {
#Relationship(type="PARENT", direction = Relationship.INCOMING)
public List<BoardPosition> children;
I have a query returning a target BoardPosition and I need it's children to be populated.
#Query("MATCH (target:BoardPosition) <-[c:PARENT]- (child:BoardPosition)
WHERE target.play={Play}
RETURN target, c, child")
BoardPosition findActiveByPlay(#Param("Play") String play);
The problem is that the query appears to return one separate result for each child, and those results aren't being used to populate the array of children in the target.
Instead of Spring Neo collating the children into the array on the target, I get "only 1 result expected" error - as if the query is returning multiple results each with one child, rather than one result with the children in it.
org.springframework.dao.IncorrectResultSizeDataAccessException:
Incorrect result size: expected at most 1
How can I have a custom query to populate that target's children list?
(Note that the built-in findByPlay(play) does what I want - the built-in queries have a depth of 1 rather than 0, and it returns a target with populated children - but of course I need to make the query a bit more sophisticated than just "by Play"... that's why I need to solve this)
Versions:
org.springframework.data:spring-data-neo4j:5.1.3.RELEASE
neo4j 3.5.0
=== Edit ======
Your problem arises because you have self-relationship (relationship between nodes of the same label)
This is how Spring treat your query for single node:
org.springframework.data.neo4j.repository.query.GraphQueryExecution
#Override
public Object execute(Query query, Class<?> type) {
Iterable<?> result;
....
Object ret = iterator.next();
if (iterator.hasNext()) {
throw new IncorrectResultSizeDataAccessException("Incorrect result size: expected at most 1", 1);
}
return ret;
}
Spring passes your node class type Class<?> type to neo4j-ogm and have your data read back.
You know, neo4j server will returns multiple rows for your query, one for each matching path:
A <- PARENT - B
A <- PARENT - C
A <- PARENT - D
If your nodes are of different labels, i.e. of different class type then the ogm only return single node correspond to your query return type, no problem.
But your nodes are of the same labels, i.e. same class type => Neo4j OGM cannot distinguish which is the returned node -> All nodes A, B, C, D returned -> Exception
Regard this issue, I think you should file a bug report now.
For workaround, you can can change the query to return only the distinct target.your_identity_property (identity_property is 'primary key' of the node, which uniquely identify your node)
Then have your application call load with the that identity property:
public interface BoardRepository extends CrudRepository<BoardPos, Long> {
#Query("MATCH (target:B) <-[c:PARENT]- (child:B) WHERE target.play={Play} RETURN DISTINCT target.your_identity_property")
Long findActiveByPlay(#Param("Play") String play);
BoardPos findByYourIdentityProperty(xxxx);
}
=== OLD ======
Spring docs says that (highlighted by me):
Custom queries do not support a custom depth. Additionally, #Query does not support mapping a path to domain entities, as such, a path should not be returned from a Cypher query. Instead, return nodes and relationships to have them mapped to domain entities.
So clearly your use-case (populate children nodes by custom query) is supported. Spring framework already maps the results into a single node. (Indeed, my setup on local turnouts that the operation is working properly)
So your exception may be caused by several issues:
You have more than one target:BoardPosition with target.play={play}. So the exception refers to more than one target:BoardPosition instead of one BoardPosition with multiple child result
You have incorrect entity mapping. Do you have your mapping field annotated with #Relationship with correct direction attribute? You might post your entity here.
Here is my local setup:
#NodeEntity(label = "C")
#Data
public class Child {
#Id
#GeneratedValue
private long id;
private String name;
#Relationship(type = "PARENT", direction = "INCOMING")
private List<Parent> parents;
}
public interface ChildRepository extends CrudRepository<Child, Long> {
#Query("MATCH (target:C) <-[p:PARENT]- (child:P) "
+ "WHERE target.name={name} "
+ "RETURN target, p, child")
Child findByName(#Param("name") String name);
}
(:C) <-[:PARENT] - (:P)
Consider the alternative query
MATCH (target:BoardPosition {play:{Play}})
RETURN target, [ (target)<-[c:PARENT]-(child:BoardPosition) | [c, child] ]
which is using list comprehension to return not only the target but also its relations and related nodes of label BoardPosition within one result row. This ensures that the result will be a single row (as long as your attribute play is unique).
I didn't try it with your example but in my application this approach is working fine. Neo4j OGM hydrates the objects as expected. It is important to include the related nodes as well as the relations pointing to the nodes.
If you enable neo4j OGM logs, you can see that the build-in queries with depth 1 use the same approach.
I've modified an existing RESTful/JDBC application i have to work with new features in Spring 4... specifically the JpaRepository. It will:
1) Retrieve a list of transactions for a specified date. This works fine
2) Retrieve a count of transactions by type for a specified date. This is not working as expected.
The queries are setup similarly, but the actual return types are very different.
I have POJOs for each query
My transactions JPA respository looks like:
public interface MyTransactionsRepository extends JpaRepository<MyTransactions, Long>
//My query works like a charm.
#Query( value = "SELECT * from ACTIVITI_TMP.BATCH_TABLE WHERE TO_CHAR(last_action, 'YYYY-MM-DD') = ?1", nativeQuery = true )
List< MyTransactions > findAllBy_ToChar_LastAction( String lastActionDateString );
This returns a list of MyTransactions objects as expected. Debugging, i see the returned object as ArrayList. Looking inside the elementData, I see that each object is, as expected, a MyTransactions object.
My second repository/query is where i'm having troubles.
public interface MyCountsRepository extends JpaRepository<MyCounts, Long>
#Query( value = "SELECT send_method, COUNT(*) AS counter FROM ACTIVITI_TMP.BATCH_TABLE WHERE TO_CHAR(last_action, 'YYYY-MM-DD') = ?1 GROUP BY send_method ORDER BY send_method", nativeQuery = true )
List<MyCounts> countBy_ToChar_LastAction( String lastActionDateString );
This DOES NOT return List as expected.
The object that holds the returned data was originally defined as List, but when I inspect this object in Eclipse, I see instead that it is holding an ArrayList. Drilling down to the elementData, each object is actually an Object[2]... NOT a MyCounts object.
I've modified the MyCountsRepository query as follows
ArrayList<Object[]> countBy_ToChar_LastAction( String lastActionDateString );
Then, inside my controller class, I create a MyCounts object for each element in List and then return List
This works, but... I don't understand why i have to go thru all this?
I can query a view as easily as a table.
Why doesn't JPA/Hibernate treat this as a simple 2 column table? send_method varchar(x) and count (int or long)
I know there are issues or nuances for how JPA treats queries with counts in them, but i've not seen anything like this referenced.
Many thanks for any help you can provide in clarifying this issue.
Anthony
That is the expected behaviour when you're doing a "group by". It will not map to a specific entity. Only way this might work is if you had a view in your database that summarized the data by send_method and you could map an entity to it.