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How to map java enum to postgreSQL enum for conditional select query

I am using PostgreSQL and java for building the backend of an application.
In PostgreSQL, I have used an enum here.
and in java I have used enum for layer variable also.
#Entity
#Getter
#Setter
#Table(name = "usecase_details")
#JsonIgnoreProperties
public class UsecaseDetails {
#Id
#Column(name="id", nullable = false)
#SequenceGenerator(name= "usecase_details_sequence", sequenceName
="usecase_details_id_sequence")
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator =
"usecase_details_sequence" )
private Long id;
#Column(columnDefinition = "layer_t", nullable = false)
#Enumerated(EnumType.STRING)
#Type(type = "com.apple.exampleportal.portal.utility.EnumTypePostgreSql")
private Layer layer;
private Long check_id;
private int usecase_id;
private String description;
private String fix_type;
private String radars;
private boolean show_usecase = true;
public UsecaseDetails(Long id, Layer layer, Long check_id, int usecase_id, String description, String fix_type, String radars, boolean show_usecase) {
this.id = id;
this.layer = layer;
this.check_id = check_id;
this.usecase_id = usecase_id;
this.description = description;
this.fix_type = fix_type;
this.radars = radars;
this.show_usecase = show_usecase;
}
// skipping getter setter for brevity
EnumTypePostgreSql. class is
public class EnumTypePostgreSql extends EnumType {
#Override
public void nullSafeSet(
PreparedStatement st,
Object value,
int index,
SharedSessionContractImplementor session)
throws HibernateException, SQLException {
st.setObject(
index,
value != null ?
((Enum) value).name() :
null,
Types.OTHER
);
}
}
and my custom queries are as follows:
public interface UsecaseRepository extends JpaRepository<UsecaseDetails, Long> {
#Query(value = "SELECT description, fix_type, usecase_id, layer FROM public.usecase_details WHERE layer = :layer", nativeQuery = true)
List<UsecaseDetails> findUsecaseByLayer(Layer layer);
#Query(value = "INSERT INTO public.usecase_details(description,fix_type, usecase_id, layer)\n"+
"\tVALUES (?,?,?,?)", nativeQuery = true)
UsecaseDetails insertDetails(UsecaseDetails usecaseDetails);
The insert query is working properly but for findUsecaseByLayer , I am getting the following error.
I am unable to detect my mistake. Please help!

There's probably something wrong with how you declare the type in EnumTypePostgreSql.
I also noticed this in your custom query: WHERE layer: = ?layer is the : wanted before your equal?
The solution I use:
Remove the #Type annotation from your entity column
#Column(columnDefinition = "layer_t", nullable = false)
#Enumerated(EnumType.STRING)
private Layer layer;
Then add to your JDBC URI:
?stringtype=unspecified
This will automatically cast the string to its enum type.

ClassCastException with hibernate

I am trying to fetch specific fields from my entities. I need the result in my entity structure.
Following are my entities:
Country
public class CountryModel {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "CmtID")
private int id;
#Column(name = "CmtName")
private String name;
#JoinColumn(name="CmtStateID")
#OneToMany(targetEntity=StateModel.class,fetch=FetchType.EAGER)
private List<StateModel> state;
}
State
public class StateModel {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "SmtID")
private int id;
#Column(name = "SmtName")
private String name;
}
Following is the HQL query am executing:
Query query = session.createQuery("select c.name, s.name from CountryModel c join c.state s where c.id=2");
CountryModel stateModel = (CountryModel) query.uniqueResult();
But am getting the following error:
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.muziris.entity.CountryModel
Thanks for helping.
Expected result:
Country :
name : india
state :
name : kerala
name : goa
name : Pak
state :
name : karachi

Since your classes are mapped you can try:
Query query = session.createQuery("from CountryModel c where c.id=2");
CountryModel countryModel = (CountryModel) query.uniqueResult();
Let's make use of the mapping and HQL.
From there you can use a DTO to have only the data that you need
public CountryDTO transform(CountryModel cm){
String countryName = cm.getName();
List<String> stateNames = cm.getState().stream.map(StateModel::getName)
.collect(Collectors.toList());
return new CountryDTO(countryName, stateNames);
}
CountryDTO is the result that you need.

Hibernate returns List<Object[]> when you use the projections.
List<Object[]> is a list of specified projection columns.
Some links
https://stackoverflow.com/a/36883968/3405171
How to transform a flat result set using Hibernate

"Fail to convert to internal representation" while accessing changed column data with audit query

I am using envers in my project to audit data.
Now I want to access changed data with audit query.
My pojo class for table is below
#Entity
#Audited(withModifiedFlag=true)
#Table(name = "INSTRUMENT", uniqueConstraints = #UniqueConstraint(columnNames = "INSTRUMENT_NAME"))
public class Instrument implements java.io.Serializable {
private long instrumentId;
private String instrumentName;
private WorkflowState workflowState;
#Id
#Column(name = "INSTRUMENT_ID", unique = true, nullable = false, precision = 22, scale = 0)
public long getInstrumentId() {
return this.instrumentId;
}
public void setInstrumentId(long instrumentId) {
this.instrumentId = instrumentId;
}
#Column(name = "INSTRUMENT_NAME", unique = true, nullable = false, length = 50)
public String getInstrumentName() {
return this.instrumentName;
}
public void setInstrumentName(String instrumentName) {
this.instrumentName = instrumentName;
}
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "STATUS", nullable = false)
public WorkflowState getWorkflowState() {
return this.workflowState;
}
public void setWorkflowState(WorkflowState workflowState) {
this.workflowState = workflowState;
}
}
Now I tried to access this with audit query as
AuditQuery query = reader.createQuery().forRevisionsOfEntity(Instrument.class, false, true)
.add(AuditEntity.property("status").hasChanged());
List list= query.getResultList();
So at the time of accessing getResultList() , Its throwing Exception as follows
SqlExceptionHelper: Fail to convert to internal representation
I figured it out, this is because in my db Instrument.status column is as String data Type. While here I am using Join.
So please tell me how to write query to resolve this problem
PROBLEM is How to write Audit Query if my table has foreign key (class property have join dependency).
Join table WorkflowState discription is as follows
public class WorkflowState implements java.io.Serializable {
private BigDecimal stateId;
private Workflow workflow;
private String stateName;
//getters and setters
And it has a join column too i.e "workflow" .

Use workflowState rather than status. The API is based on you specifying the property name and not the column name.

hibernate filter not working in the case of session.get() but working in the case of session.createQuery()

I am using hibernate 4. I am writing a filter. The strange thing I noticed is the filter is not getting applied if I use session.get() method
public SecurityAgency getSecurityAgencyById(int id) {
Session session = this.sessionFactory.getCurrentSession();
session.enableFilter("byEnabled");
SecurityAgency s = (SecurityAgency)session.get(SecurityAgency.class, new Integer(id));
return s;
}
Filter starts working as soon as I replace the session.get method with session.createQuery method and send a HQL query. I am unable to find any reason for this behaviour in the hibernate documentation.
FIlter declaration in securtiy agency class
#Entity
#Table(name="security_agency")
public class SecurityAgency implements java.io.Serializable {
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(name="name")
private String name;
#Column(name="code")
private String code;
#Column(name="website")
private String website;
#Column(name="tan")
private String tan;
#Column(name="email")
private String email;
#Column(name="pan")
private String pan;
#Column(name="created_at")
private Date createdAt;
#Column(name="created_by")
private long createdBy;
#Column(name="modified_at")
private Date modifiedAt;
#Column(name="modified_by")
private long modifiedBy;
#OneToMany(mappedBy="securityAgency",fetch = FetchType.EAGER)
#JsonIgnoreProperties("securityAgency")
#Filter(name = "byEnabled", condition = "is_enabled= 1")
private Set<ContactPerson> contactPersons = new HashSet<ContactPerson>(0);
public SecurityAgency() {
}
Contact person class
#Entity
#Table(name = "contact_person")
#FilterDefs({
#FilterDef(name="byEnabled"),
#FilterDef(name="bySecurityAgency",parameters = #ParamDef(name="agency_id", type="int"))
})
#Filters({
#Filter(name="byEnabled", condition = "is_enabled = 1"),
#Filter(name="bySecurityAgency", condition = "agency_id= :agency_id ")
})
public class ContactPerson implements java.io.Serializable {

Filter doesn't work if you are fetching using id value.Use Query interface instead. See this thread

if you want to use table column values you need to use filter join table ( #FilterJoinTable ), #Filter is applied to target entity rather than table
try,
#FilterJoinTable(name = "byEnabled", condition = "is_enabled= :enabled")
private Set<ContactPerson> contactPersons = new HashSet<ContactPerson>(0);
get
session.enableFilter("byEnabled").setParameter("enabled", Integer.valueOf(1));

Spring-MVC, Hibernate : Creating DTO objects from Domain objects

I am working on a Spring-MVC application in which I am trying to search for List of GroupNotes in database. The mapping in my project is GroupCanvas has one-to-many mapping with GroupSection and GroupSection has one-to-many mapping with GroupNotes. Because of these mappings, I was getting LazyInitializationException. As suggested on SO, I should be converting the objects to a DTO objects for transfer. I checked on net, but couldnt find a suitable way to translate those.
I have just created a new List to avoid the error, but one field is still giving me an error. I would appreciate if anyone tells me either how to fix this error or convert the objects to a DTO objects so they can be transferred.
Controller code :
#RequestMapping(value = "/findgroupnotes/{days}/{canvasid}")
public #ResponseBody List<GroupNotes> findGroupNotesByDays(#PathVariable("days")int days, #PathVariable("canvasid")int canvasid){
List<GroupNotes> groupNotesList = this.groupNotesService.findGroupNotesByDays(days,canvasid);
List<GroupNotes> toSendList = new ArrayList<>();
for(GroupNotes groupNotes : groupNotesList){
GroupNotes toSendNotes = new GroupNotes();
toSendNotes.setMnotecolor(groupNotes.getMnotecolor());
toSendNotes.setNoteCreationTime(groupNotes.getNoteCreationTime());
toSendNotes.setMnotetag(groupNotes.getMnotetag());
toSendNotes.setMnotetext(groupNotes.getMnotetext());
toSendNotes.setAttachCount(groupNotes.getAttachCount());
toSendNotes.setNoteDate(groupNotes.getNoteDate());
toSendList.add(toSendNotes);
}
return toSendList;
}
GroupNotesDAOImpl :
#Override
public List<GroupNotes> searchNotesByDays(int days, int mcanvasid) {
Session session = this.sessionFactory.getCurrentSession();
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DAY_OF_YEAR, -days);
long daysAgo = cal.getTimeInMillis();
Timestamp nowMinusDaysAsTimestamp = new Timestamp(daysAgo);
GroupCanvas groupCanvas = (GroupCanvas) session.get(GroupCanvas.class,mcanvasid);
Query query = session.createQuery("from GroupSection as n where n.currentcanvas.mcanvasid=:mcanvasid");
query.setParameter("mcanvasid", mcanvasid);
List<GroupSection> sectionList = query.list();
List<GroupNotes> notesList = new ArrayList<GroupNotes>();
for (GroupSection e : sectionList) {
System.out.println("Section name is "+e.getMsectionname());
GroupSection groupSection = (GroupSection) session.get(GroupSection.class,e.getMsectionid());
Query query1 = session.createQuery("from GroupNotes as gn where gn.ownednotes.msectionid=:msectionid and gn.noteCreationTime >:limit");
query1.setParameter("limit", nowMinusDaysAsTimestamp);
query1.setParameter("msectionid",e.getMsectionid());
notesList.addAll(query1.list());
}
// I am getting the data below, but I get JSON errors.
for(GroupNotes groupNotes : notesList){
System.out.println("Group notes found are "+groupNotes.getMnotetext());
}
return notesList;
}
GroupCanvas model :
#Entity
#Table(name = "membercanvas")
public class GroupCanvas{
#OneToMany(mappedBy = "currentcanvas",fetch=FetchType.LAZY, cascade = CascadeType.REMOVE)
#JsonIgnore
private Set<GroupSection> ownedsection = new HashSet<>();
#JsonIgnore
public Set<GroupSection> getOwnedsection() {
return this.ownedsection;
}
public void setOwnedsection(Set<GroupSection> ownedsection) {
this.ownedsection = ownedsection;
}
}
GroupSection model :
#Entity
#Table(name = "membersection")
public class GroupSection{
#OneToMany(mappedBy = "ownednotes", fetch = FetchType.EAGER,cascade = CascadeType.REMOVE)
#JsonIgnore
private Set<GroupNotes> sectionsnotes = new HashSet<>();
public Set<GroupNotes> getSectionsnotes(){
return this.sectionsnotes;
}
public void setSectionsnotes(Set<GroupNotes> sectionsnotes){
this.sectionsnotes=sectionsnotes;
}
}
GroupNotes model :
#Entity
#Table(name="groupnotes")
public class GroupNotes{
#Id
#Column(name="mnoteid")
#GeneratedValue(strategy = GenerationType.SEQUENCE,generator = "mnote_gen")
#SequenceGenerator(name = "mnote_gen",sequenceName = "mnote_seq")
#org.hibernate.annotations.Index(name = "mnoticesidindex")
private int mnoticesid;
#Column(name = "mnotetext")
private String mnotetext;
#Column(name = "mnoteheadline")
private String mnotetag;
#Column(name = "mnotecolor")
private String mnotecolor;
#Column(name = "mnoteorder")
private double mnoteorder;
#Column(name = "attachmentcount")
private int attachCount;
#Column(name = "notedate")
private String noteDate;
#Column(name = "uploader")
private String uploader;
#Column(name = "activeedit")
private boolean activeEdit;
#Column(name = "notedisabled")
private boolean noteDisabled;
#Column(name = "noteinactive")
private boolean noteInActive;
#Column(name = "notecreatoremail")
private String noteCreatorEmail;
#Column(name = "prefix")
private String prefix;
#Column(name = "timestamp")
private Timestamp noteCreationTime;
#Transient
private boolean notRead;
#Transient
private String tempNote;
#Transient
private String canvasUrl;
#ManyToOne
#JoinColumn(name = "msectionid")
#JsonIgnore
private GroupSection ownednotes;
#JsonIgnore
public GroupSection getOwnednotes(){return this.ownednotes;}
public void setOwnednotes(GroupSection ownednotes){this.ownednotes=ownednotes;}
#JsonIgnore
public int getOwnedSectionId(){
return this.ownednotes.getMsectionid();
}
#OneToMany(mappedBy = "mnotedata",fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
#JsonIgnore
private Set<GroupAttachments> mattachments = new HashSet<>();
public Set<GroupAttachments> getMattachments() {
return this.mattachments;
}
public void setMattachments(Set<GroupAttachments> mattachments) {
this.mattachments = mattachments;
}
#OneToMany(mappedBy = "mhistory",fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
#JsonIgnore
private Set<GroupNoteHistory> groupNoteHistorySet = new HashSet<>();
public Set<GroupNoteHistory> getGroupNoteHistorySet(){
return this.groupNoteHistorySet;
}
public void setGroupNoteHistorySet(Set<GroupNoteHistory> groupNoteHistorySet){
this.groupNoteHistorySet = groupNoteHistorySet;
}
#OneToMany(mappedBy = "unreadNotes",fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
#JsonIgnore
private Set<UnreadNotes> unreadNotesSet = new HashSet<>();
public Set<UnreadNotes> getUnreadNotesSet(){
return this.unreadNotesSet;
}
public void setUnreadNotesSet(Set<UnreadNotes> unreadNotesSet){
this.unreadNotesSet = unreadNotesSet;
}
//getters and setters ignored
}
Error log :
org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: (was java.lang.NullPointerException) (through reference chain: java.util.ArrayList[0]->com.journaldev.spring.model.GroupNotes["ownedSectionId"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: java.util.ArrayList[0]->com.journaldev.spring.model.GroupNotes["ownedSectionId"])
Kindly let me know what to do, as I am stuck on that error since some time.

What I think that happens is Jackson tries to serialize all fields in the hierarchy based on getter methods. In some situation NullPointerException is thrown in the following method:
#JsonIgnore
public int getOwnedSectionId(){
return this.ownednotes.getMsectionid();
}
replace it with the following method:
#JsonIgnore
public int getOwnedSectionId(){
if(this.ownednotes != null)
return this.ownednotes.getMsectionid();
return 1;
}
I don't have an explanation why jackson tries to serialize it when is market with #JsonIgnore but you can give a try with my proposal

I would appreciate if anyone tells me either how to fix this error or convert the objects to a DTO objects so they can be transferred.
We use DozerMapper at work for this purpose.

Instead of doing that mapping manually you might want to take a look at Blaze-Persistence Entity Views which can be used to efficiently implement the DTO pattern with JPA. Here a quick code sample how your problem could be solved
First you define your DTO as entity view
#EntityView(GroupNotes.class)
public interface GroupNoteView {
#IdMapping("mnoticesid") int getId();
String getMnotecolor();
String getMnotetag();
String getMnotetext();
String getNoteDate();
Timestamp getNoteCreationTime();
int getAttachCount();
}
Next you adapt your DAO to make use of it
#Override
public List<GroupNoteView> searchNotesByDays(int days, int mcanvasid) {
EntityManager entityManager = // get the entity manager from somewhere
CriteriaBuilderFactory cbf = // factory for query building from Blaze-Persistence
EntityViewManager evm = // factory for applying entity views on query builders
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DAY_OF_YEAR, -days);
long daysAgo = cal.getTimeInMillis();
Timestamp nowMinusDaysAsTimestamp = new Timestamp(daysAgo);
CriteriaBuilder<GroupNotes> cb = cbf.create(entityManager, GroupNotes.class, "note")
.where("noteCreationTime").gt(nowMinusDaysAsTimestamp)
.where("ownednotes.ownedcanvas.mcanvasid").eq(mcanvasid);
return evm.applySetting(EntityViewSetting.create(GroupNoteView.class), cb)
.getResultList();
}
And finally the calling code
#RequestMapping(value = "/findgroupnotes/{days}/{canvasid}")
public #ResponseBody List<GroupNoteView> findGroupNotesByDays(#PathVariable("days")int days, #PathVariable("canvasid")int canvasid){
return this.groupNotesService.findGroupNotesByDays(days, canvasid);
}