I have an Entity class with a column attribute whose type is an abstract class. I want to serialize (object to JSON string) while saving it in the database column and deserialize it into an abstract class (which in turn converts the string to the appropriate concrete class) when it is retrieved from the database.
Here's how I accomplished it:
ProductEntity.java
#Entity
#Table(name="PRODUCT")
#Data
public class ProductEntity{
#Id
#Column(name = "ID", insertable = false)
#GeneratedValue(strategy = GenerationType.IDENTITY)
private BigInteger id;
#Column(name = "DESCRIPTION")
private String description;
#Column(name = "NAME")
private String name;
#Column(name = "PRODUCT_TYPE")
private String productType;
#Column(name = "PRODUCT_SPECS")
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.EXTERNAL_PROPERTY, property =
"productType") // -------------------> Map to concrete class based on productType value
#Convert(converter = ObjectConverter.class) // ------------> custom converter
private ProductSpecification productSpec;
}
NOTE : "PRODUCT_SPECS" database column is of JSON type.
ProductSpecification.java
#NoArgsConstructor
#JsonTypeInfo(use = JsonTypeInfo.Id.MINIMAL_CLASS,
include = JsonTypeInfo.As.WRAPPER_OBJECT,
#JsonSubTypes({
#JsonSubTypes.Type(value = ComputerSpecification.class, name = "computer"),
#JsonSubTypes.Type(value = SpeakerSpecification.class, name = "speaker")
})
public abstract class ProductSpecification{ }
ComputerSpecification.java
#Getter
#Setter
#NoArgsConstructor
#JsonTypeName("computer")
public class ComputerSpecification extends ProductSpecification {
String memory;
String displaySize;
String processor;
#JsonCreator
public ComputerSpecification (#JsonProperty("memory") String memory,
#JsonProperty("displaysize") String displaySize,
#JsonProperty("processor") String processor){
super();
this.memory = memory;
this.displaySize = displaySize;
this.processor = processor;
}
}
SpeakerSpecification.java
#Getter
#Setter
#NoArgsConstructor
#JsonTypeName("computer")
public class SpeakerSpecification extends ProductSpecification {
String dimension;
String sensitivity;
String bassPrinciple;
String amplifierPower;
#JsonCreator
public SpeakerSpecification (#JsonProperty("sensitivity") String sensitivity,
#JsonProperty("dimension") String dimension,
#JsonProperty("bassPrinciple") String bassPrinciple,
#JsonProperty("amplifierPower") String amplifierPower){
super();
this.sensitivity = sensitivity;
this.dimension = dimension;
this.bassPrinciple = bassPrinciple;
this.amplifierPower = amplifierPower;
}
}
ObjectConverter.java
NOTE: I am using Jackson ObjectMapper for serialization and deserialization.
public class ObjectConverter implements AttributeConverter<Object, String>{
private final static Logger LOGGER = LoggerFactory.getLogger(ObjectConverter.class);
private static final ObjectMapper mapper;
static {
mapper = new ObjectMapper();
mapper.setSerializationInclusion(Include.NON_NULL);
}
#Override
public String convertToDatabaseColumn(Object attributeObject) {
if (attributeObject == null) {
return "";
}
try {
return mapper.writeValueAsString(attributeObject);
} catch (JsonProcessingException e) {
LOGGER.error("Could not convert to database column", e);
return null;
}
}
#Override
public Object convertToEntityAttribute(String dbColumnValue) {
try {
if (StringUtils.isBlank(dbColumnValue)) {
return null;
}
return mapper.readValue(dbColumnValue, ProductSpecification.class); // ----> mapped to
abstract class
} catch (Exception e) {
LOGGER.error("Could not convert to entity attribute", e);
return null;
}
}
}
Request body 1:
{
"name" : "Bose Bass Module 700 - Black- Wireless, Compact Subwoofer",
"description" : "This wireless, compact subwoofer is designed to be paired with the Bose sound
bar 700 to bring music, movies, and TV to life with Deep, dramatic bass. ",
"productSpec" : {
"sensitivity" : "90 dB",
"bassPrinciple" : "reflex",
"amplifierPower" : "700 watts",
"dimension" : "14-5/16inW x 42-13/16inH x 16-5/16inD"
}
}
This request gets saved in the database column "PRODUCT_SPECS" as :
{".SpeakerSpecification ":{"sensitivity" : "90 dB","bassPrinciple" : "reflex", "amplifierPower" :"700
watts", "dimension" : "14-5/16inW x 42-13/16inH x 16-5/16inD" }}
Now this solution works perfectly fine. The "SpeakerSpecification " key neither appears in the response of GET API call nor in the swagger doc. But having to store the type info in the database really bothers me.
Is there a better approach to this problem where I could avoid having the typeinfo (".SpeakerSpecification ") in the column value?
Related
There is an entity :
#Entity
#Table(name = "ITMMASTER" , schema = "TOMCTB")
public class Article {
#Id
#Column(name = "ITMREF_0")
private String code_article;
#Column(name = "ACCCOD_0")
private String acccod;
public String getCode_article() {
return code_article;
}
public void setCode_article(String code) {
this.code_article = code;
}
public String getAcccod() {
return acccod;
}
public void setAcccod(String acccod) {
this.acccod = acccod;
}
}
I want to make the schema attribute to be dynamic depending on a properties file property value , for example : env.schema = TOMEXPL.
How to achieve that ?
I didn't tried it but I guess this should work.
public class DynamicNamingStrategy extends DefaultNamingStrategy {
#Value("db.table.name")
private String name;
#Override
public String tableName(String tableName) {
return name;
}
...
}
SessionFactory sessionFactory;
Configuration config = new AnnotationConfiguration()
.configure("hibernate.cfg.xml")
.setNamingStrategy( new DynamicNamingStrategy() );
sessionFactory = config.buildSessionFactory();
session = sessionFactory.openSession();
I have a class in my domain called Activity that looks like the following
#JsonIdentityInfo(generator=ObjectIdGenerators.PropertyGenerator.class, property="id")
#NodeEntity
public class Activity {
#GraphId
private Long id;
private String title;
private String description;
#Relationship(type = "RELATED_TO", direction = Relationship.UNDIRECTED)
private List<Activity> relatedActivities = new ArrayList<>();
public Activity() {
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public String getDescription() {
return description;
}
public Collection<Activity> getRelatedActivities() {
System.out.println("getting relatedActivities");
System.out.println(relatedActivities);
return relatedActivities;
}
public void addRelatedActivity(Activity activity) {
this.relatedActivities.add(activity);
}
}
I create relationships using the following repository class:
#RepositoryRestResource(collectionResourceRel = "relationships", path = "relationships")
public interface RelationshipRepository extends GraphRepository<Relationship> {
#Query("MATCH (a1:Activity), (a2:Activity) " +
"WHERE a1.title = {0} AND a2.title = {1}" +
"CREATE (a1)-[:RELATED_TO]->(a2)")
void addRelationship(String a1Title, String a2Title);
}
I have verified that this code works using the neo4j browser, which lets me see existing nodes and relationships between them. However, when I access getRelatedActivities() on an Activity object, it's always an empty array, even if that Activity has other Activity nodes related to it, clearly visible in neo4j.
How can I get the relatedActivites on an Activity to automatically populate based on its relationships correctly?
The problem in your code is that you define the "target" as an Activity here
#Relationship(type = "RELATED_TO", direction = Relationship.UNDIRECTED)
private List<Activity> relatedActivities = new ArrayList<>();
but you also have a RelationshipEntity class in your code base: Relationship with the same type RELATED_TO.
When OGM gets the result it tries to match every field but since it converts the relationship type RELATED_TO to the RelationshipEntity and not an Activity object, it does not fill the list in the Activity class.
I have two methods (in a Spring boot application) that handle an entity. The entity has two fields, both boolean isDefault and isPdfGenerated. The first method (which is called from a controller) changes the isDefault flag when a new entity is created while the second one (called from a #Scheduled annotated method) changes the isPdfGenrated after it generates a pdf file for that entity.
My problem is that sometimes the second method finds entities with the isPdfGenerated flag set to false even though the file has been generated and saved in the database.
Both the methods have the #Transactional annotation and the repository interface for the entity extends JpARepository.
My guess is that the first method loads the entity from the database before the second method does but saves the entity after the second method does its job, thus overriding the isPdfGenerated flag.
Is this possible ? If the answer is yes, how should one handle such cases ? Shouldn't JPARepository handle the case when an entity gets updated from an external source ?
Bellow is some code to better illustrate the situation.
MyController:
#Controller
#RequestMapping("/customers")
public class MyController {
#Autowired
private EntityService entityService;
#RequestMapping(value = "/{id}/changeDefault", method = RequestMethod.POST)
public String changeDefault(#PathVariable("id") Long customerId, #ModelAttribute EntityForm entityForm, Model model) {
Entity newDefaultEntity = entityService.updateDefaultEntity(customerId, entityForm);
if (newDefaultEntity == null)
return "redirect:/customers/" + customerId;
return "redirect:/customers/" + customerId + "/entity/default;
}
}
EntityService:
import org.springframework.transaction.annotation.Transactional;
#Service
public class EntityService {
#Autowired
private EntityRepository entityRepository;
#Autowired
private CustomerRepository customerRepository;
#Transactional
public Entity updateDefaultEntity(Long customerId, submittedData) {
Customer customer = customerRepository.findById(customerId);
if(customer == null)
return customer; // I know there are better ways to do this
Entity currentDefaultEntity = entityRepository.findUniqueByCustomerAndDefaultFlag(customer, true);
if(currentDefaultEntity == null)
return null; // I know there are better ways to do this also
Entity newDefaultEntity = new Entity();
newDefaultEntity.setField1(submittedData.getField1());
newDefaultEntity.setField2(submittedData.getField2());
newDefaultEntity.setCustomer(customer);
oldDefaultEntity.setDefaultFlag(false);
newDefaultEntity.setDefaultFlag(true);
entityRepository.save(newDefaultEntity);
}
#Transactional
public void generatePdfDocument(Entity entity) {
Document pdfDocument = generateDocument(entity);
if(pdfDocument == null)
return;
documentRepository.save(pdfDocument);
entity.setPdfGeneratedFlag(true);
entityRepository.save(entity);
}
}
ScheduledTasks:
#Component
public class ScheduledTasks {
private static final int SECOND_IN_MILLISECONDS = 1000;
private static final int MINUTE_IN_SECONDS = 60;
#Autowired
private EntityRepository entityRepository;
#Autowired
private DocumentService documentService;
#Scheduled(fixedDelay = 20 * SECOND_IN_MILLISECONDS)
#Transactional
public void generateDocuments() {
List<Quotation> quotationList = entityRepository.findByPdfGeneratedFlag(false);
for(Entity entity : entitiesList) {
documentService.generatePdfDocument(entity);
}
}
}
DocumentService:
#Service
public class DocumentService {
#Autowired
private EntityRepository entityRepository;
#Autowired
private DocumentRepository documentRepository;
#Transactional
public void generatePdfDocument(Entity entity) {
Document pdfDocument = generateDocument(entity);
if(pdfDocument == null)
return;
documentRepository.save(pdfDocument);
entity.setPdfGeneratedFlag(true);
entityRepository.save(entity);
}
}
EntityRepository:
#Repository
public interface EntityRepository extends JpaRepository<Entity, Long> {
Entity findById(#Param("id") Long id);
List<Entity> findByPdfGeneratedFlag(#Param("is_pdf_generated") Boolean pdfGeneratedFlag);
Entity findUniqueByCustomerAndDefaultFlag(
#Param("customer") Customer customer,
#Param("defaultFlag") Boolean defaultFlag
);
}
DocumentRepository:
#Repository
public interface DocumentRepository extends JpaRepository<Document, Long> {
Document findById(#Param("id") Long id);
}
Entity:
#Entity
#Table(name = "entities")
#JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "id")
public class Entity {
private Long id;
private boolean defaultFlag;
private boolean pdfGeneratedFlag;
private String field1;
private String field2;
private Customer customer;
public Entity() { }
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
#Column(name = "is_default")
public boolean isDefaultFlag() {
return defaultFlag;
}
public void setDefaultFlag(boolean defaultFlag) {
this.defaultFlag = defaultFlag;
}
#Column(name = "is_pdf_generated")
public boolean isPdfGeneratedFlag() {
return pdfGeneratedFlag;
}
public void setPdfGeneratedFlag(boolean pdfGeneratedFlag) {
this.pdfGeneratedFlag = pdfGeneratedFlag;
}
#Column(name = "field_1")
public String getField1() {
return field1;
}
public void setField1(String field1) {
this.field1 = field1;
}
#Column(name = "field_2")
public String getField2() {
return field2;
}
public void setField2(String field2) {
this.field2 = field2;
}
#ManyToOne
#JoinColumn(name = "customer_id", referencedColumnName = "id", nullable = false)
public Customer getCustomer() {
return customer;
}
public void setCustomer(Customer customer) {
this.customer = customer;
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Entity quotation = (Entity) o;
return id != null ? id.equals(entity.id) : entity.id == null;
}
#Override
public int hashCode() {
return id != null ? id.hashCode() : 0;
}
#Override
public String toString() {
return "Entity{" +
"id=" + id +
", pdfGeneratedFlag=" + pdfGeneratedFlag +
", defaultFlag=" + defaultFlag +
", field1=" + field1 +
", field2=" + field2 +
", customer=" + (customer == null ? null : customer.getId()) +
"}";
}
}
I have omitted the other classes because they are either POJOs ( EntityForm ) or the same as other domain model classes ( Document ).
If you're talking about a row on the database that is getting updated by another process after the first process has read it but before it has been updated, then you need to put in some sort of optimistic locking strategy.
This will be handled by the underlying ORM api (e.g. Hibernate or Eclipselink) rather than Spring Data (which will just handle an optimistic locking errors thrown by the ORM).
Have a look at this article. Bear in mind that if you want optimistic locking you need some way of determining a row's version. In JPA this is normally done using a column annotated with the #Version tag.
https://vladmihalcea.com/hibernate-locking-patterns-how-does-optimistic-lock-mode-work/
I have an error in spring JPA
org.springframework.data.mapping.PropertyReferenceException: No property CompanyId found for type CompanyUserDetail!
#Embeddable
public class CompanyUserKey implements Serializable {
public CompanyUserKey() {
}
#Column(name = "company_id")
private UUID companyId;
#Column(name = "user_name")
private String userName;
public UUID getCompanyId() {
return companyId;
}
public void setCompanyId(UUID companyId) {
this.companyId = companyId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
}
#Entity
#Table(name = "company_user_detail")
public class CompanyUserDetail {
#EmbeddedId
CompanyUserKey companyUserkey;
public CompanyUserKey getCompanyUserkey() {
return companyUserkey;
}
public void setCompanyUserkey(CompanyUserKey companyUserkey) {
this.companyUserkey = companyUserkey;
}
}
I am trying to access below method Service layer
#Component
public interface CompanyUserRepository extends JpaRepository<CompanyUserDetail, CompanyUserKey> {
public List<CompanyUserDetail> findByCompanyId(UUID companyId);
}
How can I achieve this ?
Thanks
Since in java model your CompanyUserKey is a property in the CompanyUserDetail class, I believe you should use full path (companyUserkey.companyId) to reach companyId:
public List<CompanyUserDetail> findByCompanyUserkeyCompanyId(UUID companyId);
Also note that you have a naming inconsistency: field in CompanyUserDetail is named companyUserkey instead of companyUserKey.
Assuming you are not using spring-data-jpa's auto generated implementations, your method contents might look something like the following:
FROM CompanyUserDetail c WHERE c.companyUserKey.companyId = :companyId
Now simply provide that query to the EntityManager
entityManager.createQuery( queryString, CompanyUserDetail.class )
.setParameter( "companyId", companyId )
.getResultList();
The key points are:
Query uses a named bind parameter called :companyId (not the leading :).
Parameter values are bound in a secondary step using setParameter method variants.
createQuery uses a second argument to influence type safety so that the return value from getResultList is a List<CompanyUserDetail> just like you requested.
Looking at spring-data-jpa's implementation however, I suspect it could look like this:
public interface CustomerUserRepository
extends JpaRepository<CompanyUserDetail, CompanyUserKey> {
#Query("select c FROM CompanyUserDetail c WHERE c.companyUserKey.companyId = :companyId")
List<CompanyUserDetail> findByCompanyId(#Param("companyId") UUID companyId);
}
I have this enum :
public enum DocumentTypes {
PDF("PDF Document"), JPG("Image files (JPG)"), DOC("Microsoft Word documents");
private final String displayName;
DocumentTypes(final String display) {
this.displayName = display;
}
#Override
public String toString() {
return this.displayName;
}
}
And a model like this :
#Entity
#Table(name = "documents")
public class Document extends Model {
#Id
public Long id;
#Constraints.Required
#Formats.NonEmpty
#Enumerated(EnumType.STRING)
#Column(length=20, nullable=false)
public DocumentTypes type;
#Constraints.Required
#Formats.NonEmpty
#Column(nullable=false)
public String document;
}
I match the enum using this in my controller :
DynamicForm form = form().bindFromRequest();
// ...
Document doc = new Document();
doc.type = DocumentTypes.valueOf(form.field("type").value());
doc.save();
The problem is that in database, it's stored as "Microsoft Word documents", but I would prefer to store it as DOC.
How can I do that?
You can define it very fine granular with the Anotation EnumMapping or EnumValue. This works with the old version org.avaje.ebean.
It seems that there was a complete rewrite of the code. In the actual version there is a different approach.