I use spring and hibernate. The following situation occured and I don't know if it's really possible to implement. Will appreciate any help.
For example, there is a hibernate entity
#Entity
public class TestEntity {
private String field1;
private String field2;
private String specField;
#Column(name = "field1")
public String getField1() {
return field1;
}
#Column(name = "field2")
public String getField2() {
return field2;
}
public String getSpecField() {
return (field1 != null ? field1 : field2);
}
}
And I need the value for specField to be generated by SQL query and not by java code.
Something like this
#Entity
public class TestEntity {
private String field1;
private String field2;
private String specField;
#Column(name = "field1")
public String getField1() {
return field1;
}
#Column(name = "field2")
public String getField2() {
return field2;
}
#Query(value= "COALESCE(field1, field2)")
public String getSpecField() {
return specField;
}
}
I was told that there should be ability to do so. But didn't find anything that approves this.
it's not actually important what exactly query does. I need that specField will be taken by some query and not by java code. Is it possible?
Thanks for help.
UPDATE Thanks to #premkumar, for advicing to use #Formula
So now I have
#Entity
public class TestEntity {
private String field1;
private String field2;
private String specField;
#Column(name = "field1")
public String getField1() {
return field1;
}
#Column(name = "field2")
public String getField2() {
return field2;
}
#Formula("COALESCE(field2, field2)")
public String getSpecField() {
return (field1 != null ? field1 : field2);
}
}
But app fails to start on bean initialization with
NullPointerException at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory
I tried also the following:
Put formula above "private String specField" - app started, but hibernate failed on could not find spec_field in database
Put #Formula and #Transient on getter - app started, no errors, but specField is always null. It looks like hibernate totally ignored it
If you are using hibernate, try the following:
#Formula("COALESCE(field1, field2)")
public String getSpecField() {
return specField;
}
Note:- As far as I know there is no alternative in JPA. Beware this will mixup hibernate and jpa annotations.
Why not:
public String getSpecField() {
return MoreObjects.firstNonNull(field1,field2);
}
You can leverage the JPA Callback methods:
Create a EntityListener:
public class MyEntityListener {
#PrePersist
#PreUpdate
public void prePersist(Object object) {
if(object instanceOf TestEntity ) {
object.specField = object.field1 != null ? object.field1 : object.field2
}
}
}
Annotate your class with #EntityListener:
#Entity
#EntityListeners(MyEntityListener .class)
public class TestEntity {
private String field1;
private String field2;
private String specField;
//default cons - getters and setters
}
Related
I am trying to use JPA to fetch records from database. However I am able to insert records indatabse and even get all the records using createQuery method of class EntityManager.
But in below case I am not getting why the condition in where clause is not working.
Please help me figure it out.
POJO class :
#Entity
#Table(name = "frameworks_filter")
public class FilteredFrameworksDbStructure {
#Id
#Column(name="id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(name = "regular_name")
private String regularName;
#Column(name = "component_name")
private String componentName;
#Column(name = "component_owner")
private String componentOwner;
#Column(name = "frameworks")
private String frameworks;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getRegularName() {
return regularName;
}
public void setRegularName(String regularName) {
this.regularName = regularName;
}
public String getComponentName() {
return componentName;
}
public void setComponentName(String componentName) {
this.componentName = componentName;
}
public String getComponentOwner() {
return componentOwner;
}
public void setComponentOwner(String componentOwner) {
this.componentOwner = componentOwner;
}
public String getFrameworks() {
return frameworks;
}
public void setFrameworks(String frameworks) {
this.frameworks = frameworks;
}
}
DAO class method:
public List<FilteredFrameworksDbStructure> getFilteredFrameworks(String regularName) {
EntityManager entityManager = entityManagerFactory.createEntityManager();
List<FilteredFrameworksDbStructure> filteredFrameworksDbStructureList = entityManager
.createQuery("from FilteredFrameworksDbStructure F where F.regularName = :regular", FilteredFrameworksDbStructure.class)
.setParameter("regular", regularName)
.getResultList();
return filteredFrameworksDbStructureList;
}
Issue : Condition in where clause does not work. It simply fetch all the records irrespective of the regularName provided.
Regards,
Parag Vinchurkar
Why don't you use the JpaRepository or CrudRepository to fetch your results? Check out this tutorial here and here on how to use them.
And you can use your where clause. Please see below the example repository you can use to obtain the same results as the entityManager
public interface FilteredFrameworksDbStructureRepo extends JpaRepository<FilteredFrameworksDbStructure , Integer>{
List<FilteredFrameworksDbStructure> findAllByRegularName(String regularName)
}
Please note that you will have to change your id member variable from int to Integer
I am trying to have a class that has a certain list of objects (specified by another class) persisted in the database as a string (use JPA Converter - all good).
And then I want to use Specification to search inside that string.
What is the best way to create the predicates? I don't seem to understand the connection bettween the AttributeConverter and the Expression in the Specification.
The parent class:
#Entity #Table
public class A {
#Column #Id #GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
#Column
private String name;
#Enumerated(EnumType.STRING)
private SomeType type;
#Column(length=1000) #Convert(converter = BConverter.class)
private List<B> bList;
private Integer no;
}
The listed object class:
public class B{
private String type;
private Integer quantity;
}
The converter:
#Converter
public class BConverter implements AttributeConverter<List<B>, String> {
private static final String SEPARATOR = ":";
private static final String LIST_SEPARATOR = ";";
#Override public String convertToDatabaseColumn(List<B> bList) {
return bList.stream().map(e->convertToString(e)).collect(Collectors.joining(LIST_SEPARATOR));
}
#Override public List<B> convertToEntityAttribute(String str) {
if(str==null || str.isEmpty() ) return null;
return Arrays.stream(str.split(LIST_SEPARATOR)).map(e->convertFromString(e)).collect(Collectors.toList());
}
private String convertToString(B b){
if(entity==null) return null;
return b.getType().toString() +SEPARATOR+ b.getQuantity().toString();
}
private B convertFromString(String subStr){
if(subStr==null || subStr.isEmpty() ) return null;
String[] pair = subStr.split(SEPARATOR);
return new B(pair[0],Integer.valueOf(pair[1]));
}
}
In the database should look something like:
Table A:
id: 1;
name: "Some Name";
type: "THISTYPE";
blist: "TYPE1:11;TYPE2:22";
no: 0;
id: 2;
name: "Other Name";
type: "THISTYPE";
blist: "TYPE1:45;TYPE2:56";
no: 12;
I would then like to create Specifications to search over this table for the attributes inside the bList.
For example, search by an entity that contains a B object where type=TYPE1 and a quantity>=30.
public static Specification<A> customSpecification(String type, Integer value) {
return (root, query, builder) -> ///?????????
}
Is there a way to use such specifications where the DB attribute is a String but JAVA only sees the objects?
I am new to Spring Data JPA and Hibernate. By looking at different examples I built a working model for CRUD operations on one entity, I am having trouble in joining two tables to extract AF_NAME using AF_ID from another table which is Foreign key. A null column is created with the names of and while accessing, null is returned.please check if I am following preocedure for joins and point me to any tutorial know.
I followed this solution and still there is no progress.
#Entity
#Configuration
#EnableAutoConfiguration
#Table(name = "AFF_CONFIG")
public class AFF_CONFIG implements Serializable {
#Id
#Column(name = "AFF_CONFIG_ID")
private String AFF_CONFIG_ID;
#Column(name = "AFF_ID")
private String AFF_ID;
#Column(name = "CH_ID")
private String CH_ID;
#Column(name = "M_ID")
private Long M_ID;
#Column(name = "KEY")
private String KEY;
#Column(name = "VALUE")
private String VALUE;
#Column(name = "SYSTEM")
private String SYSTEM;
private AFF aff;
#LazyCollection(LazyCollectionOption.TRUE)
#ManyToOne
#JoinColumn(name = "AFF_ID")
public AFF getAff() {
return aff;
}
public void setAffiliate(AFF aff) {
this.aff = aff;
}
public String getAFF_CONFIG_ID() {
return AFF_CONFIG_ID;
}
public void setAFF_CONFIG_ID(String aFF_CONFIG_ID) {
AFF_CONFIG_ID = aFF_CONFIG_ID;
}
public String getAFF_ID() {
return AFF_ID;
}
public void setAFF_ID(String aFF_ID) {
AFF_ID = AFF_ID;
}
public String getCH_ID() {
return CH_ID;
}
public void setCHANNEL_ID(String cH_ID) {
CH_ID = cH_ID;
}
public Long getM_ID() {
return M_ID;
}
public void setM_ID(Long m_ID) {
M_ID = m_ID;
}
public String getKEY() {
return KEY;
}
public void setKEY(String kEY) {
KEY = kEY;
}
public String getVALUE() {
return VALUE;
}
public void setVALUE(String vALUE) {
VALUE = vALUE;
}
public String getSYSTEM() {
return SYSTEM;
}
public void setSYSTEM(String sYSTEM) {
SYSTEM = sYSTEM;
}
Second entity is:
#Entity
#Table(name = "AFF")
public class AFF implements Serializable {
#Column(name = "AFF_NAME")
private String AFF_NAME;
#Column(name = "AFF_CODE")
private String AFF_CODE;
#Id
#Column(name = "AFF_ID")
private String AFF_ID;
private Set<AFF_CONFIG> someAff = new HashSet<AFF_CONFIG>();
#LazyCollection(LazyCollectionOption.TRUE)
#OneToMany(cascade = CascadeType.ALL, mappedBy = "aff")
public Set<AFF_CONFIG> getSomeAff() {
return someAff;
}
public void setSomeAff(Set<AFF_CONFIG> someAff) {
this.someAff = someAff;
}
public String getAFF_ID() {
return AFF_ID;
}
public void setAFF_ID(String aFF_ID) {
AFF_ID = aFF_ID;
}
public String getAFF_NAME() {
return AFF_NAME;
}
public void setAFF_NAME(String aFF_NAME) {
AFF_NAME = aFF_NAME;
}
public String getAFF_CODE() {
return AFF_CODE;
}
public void setAFF_CODE(String aFF_CODE) {
AFF_CODE = aFF_CODE;
}
Since this is many to one relation I created set type in one and object type in another as defined in other places.Created a repository by extending crud and added a query. Excise the bunch of different annotations, I included them in hoping to solve the null entry.
#Repository
public interface MarketRepository extends CrudRepository<AFF_CONFIG,String> {
Page<AFF_CONFIG> findAll(Pageable pageable);
#Query("Select a,b from AFF_CONFIG a, AFF b where a.AFF_ID = b.AFF_ID" )
public List<AFF_CONFIG> getAffData();
}
the applicatoin is working fine even after some tinkering until I Included these annotations. Now there is this error:
Caused by: org.hibernate.MappingException: Could not determine type for: java.util.Set, at table: aff.
I solved the issue with the help of my Supervisor. Looks like we have to follow naming specifications for Class and variables. And one more correction is to remove collection type object and change it to just object (removed set in aff class).I will post the corrected later, to compare and contrast.
i'm using spring data jpa with hibernate as provider.
i'm trying to persist my enums on varchar(enum.tostring) instead of (0,1,2)
my enum class:
public enum MagasinType {
PRINCIPAL {
#Override
public String toString() {
return "Principale".toUpperCase();
}
},
SECONDARY {
#Override
public String toString() {
return "Secondaire".toUpperCase();
}
},
MOBILE {
#Override
public String toString() {
return "Mobile".toUpperCase();
}
};
public abstract String toString();
}
my converter
#Converter(autoApply = true)
public class MagasinConverter implements attributeConverter <MagasinType,String>{
#Override
public String convertToDatabaseColumn(MagasinType magasinType) {
switch (magasinType){
case MOBILE:return "MOBILE";
case PRINCIPAL:return "PRINCIPAL";
case SECONDARY:return "SECONDARY";
default:throw new IllegalArgumentException("valeur incorrecte" + magasinType);
}
}
#Override
public MagasinType convertToEntityAttribute(String s) {
switch (s){
case "MOBILE": return MagasinType.MOBILE;
case "SECONDARY": return MagasinType.SECONDARY;
case "PRINCIPAL": return MagasinType.PRINCIPAL;
default:throw new IllegalArgumentException("valeur incorrecte" + s);
}}}
my entity
#Entity
#Table(name = "MAGASIN")
public class Magasin extends AbstractEntity {
#Column(name = "LIBELLE", nullable = false)
private String libelle;
#Column(name = "DESCR")
private String descr;
#Convert(converter = MagasinConverter.class)
private MagasinType type;
#Column(name = "LOCATION")
private String localisation;
#Version
private long version;
//getters setters omitted
}
my java config : https://gist.github.com/anonymous/480ef7a58cdcc50e7481
my app.properties : https://gist.github.com/anonymous/685eaca98fcba9c33872
and finally my test method : https://gist.github.com/anonymous/8bb60fee39a201558e19
please help me on it, i want to use #convert new jpa2.1 feature instead of
#enumerated
i tried to put the annotation on the getter and it works.
now i can call the #convert to convert enums to strings and visversa when pulling from database.
the same problem happened when i added #manytoOne on my class attribute, i got a weired problem, no column was added to the table entity.
but when i annotated the getter. every thing was ok.
please take a look at my github repo to further infos
https://github.com/zirconias/RFID_REWRITE
My application has entities with nameEn and nameDe for english and german. But only english being used now. Since there are so many entities available, I wanted to have a generic class which can return the selected language entries,but for multiple entries my approach didn't work.
#Entity
#Table(name="employee")
public class Employee implements java.io.Serializable {
// Fields
private Integer id;
private String nameEn;
private String nameDe;
//Getter, Setter Methods
}
#Entity
#Table(name="address")
public class Address implements
java.io.Serializable {
private String descriptionEn;
private String descriptionDe;
}
public interface ILabelText {
String getNameEn();
String getNameDe();
String getDescriptionEn();
String getDescriptionDe();
}
public abstract class LabelText implements ILabelText, Serializable {
private static final long serialVersionUID = 1L;
protected String descriptionEn;
protected String descriptionDe;
private Logger log = Logger.getLogger(LabelText.class);
String language = FacesContext.getCurrentInstance().getViewRoot().getLocale().getLanguage();
public String getDescription() {
log.info("Language Selected is " + language);
if (language.equals("De")) {
return getDescriptionDe();
} else {
return getDescriptionEn();
}
}
public String getName() {
log.info("Language Selected is " + language);
if (language.equals("De")) {
return getNameDe();
} else {
return getNameEn();
}
}
}
//In Xhtml, based on selected locale, display value accordingly
<h:outputText value="#{emp.getName()}" />
<h:outputText value="#{add.getDescription()}" />
You can create an entity Lang like this
#Entity
public class Lang implements Serializable
{
#Id #GeneratedValue(strategy=GenerationType.IDENTITY)
private long id;
#NotNull
private String key;
#NotNull
private String translation;
}
and use it in your Address like this
#OneToMany(cascade = CascadeType.ALL, fetch=FetchType.EAGER)
#MapKey(name = "key")
protected Map<String, Lang> name;
Then you are able to access the correct language in JSF:
<h:outputText value="#{emp.name[userLocale].translation}" />
The expression userLocale should be resolved to your language key (en, de, ...) or can be hardcoded e.g. #{emp.name['en'].translation}.
Is more easy you create a table with translations:
e.g:
People -> All of your persons
PersonTranslations
People | id
PersonTranslations | locale; person_id;
then on your Person class you set the language for all attributes on predicate
Person.description (this will search on PersonTranslation using a person_id key, and a locale)
some like that PersonTranslation.find(1, 'en');