Develop Reference

Android Room Database: stmt.bindLong(1, value.ID);

I can not fix the error when creating Room Database in Android Studio. Error: stmt.bindLong(1, value.ID);
Also in the database sql queries: "notes", "title", "id" are highlighted in red, as if there is an error here. When trying to compile, it transfers to a file - MainDAO_Impl.java. Shown in the screenshotRoom code:
package com.example.applicationnotes.DataBase;
import android.content.Context;
import androidx.room.Database;
import androidx.room.Room;
import androidx.room.RoomDatabase;
import com.example.applicationnotes.Models.Notes;
#Database(entities = Notes.class, version = 1, exportSchema = false)
public abstract class RoomDB extends RoomDatabase {
private static RoomDB database;
private static String DATABASE_NAME = "NoteApp";
public synchronized static RoomDB getInstance(Context context){
if (database == null) {
database = Room.databaseBuilder(context.getApplicationContext(),
RoomDB.class, DATABASE_NAME)
.allowMainThreadQueries()
.fallbackToDestructiveMigration()
.build();
}
return database;
}
public abstract com.example.applicationnotes.DataBase.MainDAO mainDao();
}
MainDAO:
package com.example.applicationnotes.DataBase;
import static androidx.room.OnConflictStrategy.REPLACE;
import androidx.room.Dao;
import androidx.room.Delete;
import androidx.room.Insert;
import androidx.room.Query;
import java.util.List;
import com.example.applicationnotes.Models.Notes;
#Dao
public interface MainDAO {
#Insert (onConflict = REPLACE)
void insert (Notes notes);
#Query ("SELECT * FROM notes ORDER BY id DESC")
List<Notes> getAll();
#Query("UPDATE notes SET title = :title, notes = :notes WHERE ID = :id")
void update (int id, String title, String notes);
#Delete
void delete (Notes notes);
#Query("UPDATE notes SET pinned = :pin WHERE ID = :id")
void pin (int id, boolean pin);
}
More in screenshot:-
https://i.stack.imgur.com/fEkRg.png
https://i.stack.imgur.com/VxDll.png
I tried to change requests, selectors, file names, rummaged through the SQL forums, did not find a solution to my particular problem.
Screenshots with error and SQL-request:
https://i.stack.imgur.com/fEkRg.png
https://i.stack.imgur.com/VxDll.png

I believe that you have removed the member ID from Notes (or possibly removed the Class entirely) and without then compiling the project looked at the MainDAO_Impl.
For example consider:-
#Entity
class Notes {
#PrimaryKey(autoGenerate = true)
long ID;
String title;
String notes;
String date;
boolean pinned;
}
After compiling then MainDAO_Impl is:-
Now if Notes is changed to (long ID; commented out):-
#Entity
class Notes {
#PrimaryKey(autoGenerate = true)
//long ID; /*<<<<<<<<<< COMMENTED OUT >>>>>>>>>>*/
String title;
String notes;
String date;
boolean pinned;
}
Then without compiling MainDAO_Impl is:-

Swagger UI not showing all the fields from user defined model

I am learning Swagger. I have a simple Spring Boot REST API to display employee. The Employee model has an association of employee addresses. All I am trying is to display the employee details for the documentation using Swagger.
This is my Employee model:
package com.example.documentation.model;
import io.swagger.v3.oas.annotations.media.Schema;
import java.util.Arrays;
import java.util.List;
public class Employee<T> {
#Schema(type = "int", description = "id for employee")
private int id;
#Schema(type = "string", description = "name of employee")
private String name;
private List<T> listOfAddresses;
public Employee(int id, String name, List<T> listOfAddresses) {
this.listOfAddresses = listOfAddresses;
this.id = id;
this.name = name;
}
public List<T> getListOfAddresses() {
listOfAddresses = (List<T>) Arrays.asList(new Address(2201,"Street 1","UB12
1TT"), new Address(3201,"Street 1","KK12 1TP"));
return listOfAddresses;
}
public void setListOfAddresses(List<T> listOfAddresses) {
this.listOfAddresses = listOfAddresses;
}}
where Address is a normal POJO with houseNumber, Streetname and postcode.
Below is my controller:
package com.example.documentation.controller;
import com.example.documentation.model.Address;
import com.example.documentation.model.Employee;
import io.swagger.v3.oas.annotations.Operation;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.Arrays;
import java.util.List;
#RestController
public class EmployeeController {
private Employee<Address> employee;
#RequestMapping("/employee/{id}")
#Operation(
tags = {"Employee"}
)
public Employee<Address> getEmployeeDetailsById(#PathVariable(name = "id", required = true) int id,
#PathVariable(name = "name", required = false) String name) {
List<Address> list = Arrays.asList(new Address(101,"T1","Test 1"),
new Address(201,"T2","Test 2"));
employee = new Employee<>(101,"David", list);
return employee;
}
}
I am using Gradle.
When I access Swagger UI, I see the following:
As you can see the ID and the name of the employee is missing. Any idea how to resolve this?

Save List as JSON array in postgresql

I have a List private List<Lesson> lessons; and I need to save this list to PostgreSQL database column with data type _json or json[] (JSON array). But I get one of these errors:
ERROR: column "lessons" is of type json[] but the expression is of
type character varyingorERROR: malformed array literal:
"[{"id":17,"title":"Lesson 1","part":1.0}]
How correctly serialize List to get the correct format of Postgresql JSON array?

You might need to use JsonBinaryType class from com.vladmihalcea:hibernate-types library and apply json (or jsonb) to the column definition:
// LessonList.java
import com.vladmihalcea.hibernate.type.json.JsonBinaryType;
import java.util.List;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import org.hibernate.annotations.Type;
import org.hibernate.annotations.TypeDef;
#Entity
#Table(name = "lessons")
#Getter
#Setter
#Builder
#AllArgsConstructor
#NoArgsConstructor
#TypeDef(name = "json", typeClass = JsonBinaryType.class)
public class LessonList {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#Type(type = "json")
#Column(columnDefinition = "json")
private List<Lesson> lessons;
}
SQL Script to create the table:
CREATE TABLE "lessons" (
"id" Serial NOT NULL,
"lessons" JSON NOT NULL,
"created_at" Timestamp Without Time Zone DEFAULT NOW() NOT NULL,
PRIMARY KEY ("id")
);
The rest of the classes are to provide working example:
// Lesson.java
#Getter
#Setter
#Builder
#AllArgsConstructor
#NoArgsConstructor
#ToString
public class Lesson {
private int id;
private String title;
private double part;
}
A repository extending Spring CrudRepository interface and DAO class are trivial.
A command line runner to run test:
#Slf4j
#Component
public class TestJson implements CommandLineRunner {
#Autowired
private LessonListDao dao;
#Override
public void run(String[] args) {
List<Lesson> lessons = Arrays.asList(
Lesson.builder().id(11).title("Physics").part(1.0).build(),
Lesson.builder().id(12).title("Chemistry").part(2.0).build(),
Lesson.builder().id(13).title("Biology").part(3.0).build()
);
LessonList list = LessonList.builder().lessons(lessons).build();
LessonList result = dao.save(list);
LOGGER.info("result: " + result);
List<LessonList> all = dao.findAll();
all.forEach(a -> LOGGER.info("item #" + a.getId() + "; lessons=" + a.getLessons()));
}
}
Output:
lesson.TestJson : result: lesson.LessonList#6166aac5
lesson.TestJson : item #1; lessons=[Lesson(id=1, title=Math, part=1.0), Lesson(id=2, title=English, part=2.0), Lesson(id=3, title=Informatics, part=3.0)]
lesson.TestJson : item #2; lessons=[Lesson(id=11, title=Physics, part=1.0), Lesson(id=12, title=Chemistry, part=2.0), Lesson(id=13, title=Biology, part=3.0)]
DB Data: SELECT * FROM "public".lessons:
**id** **lessons** **created_at**
[PK] Integer json timestamp without timezone
1 [{"id":1,"title":"Math","part":1.0}, 2020-06-03 18:08:55.948007
{"id":2,"title":"English","part":2.0},
{"id":3,"title":"Informatics","part":3.0}]
2 [{"id":11,"title":"Physics","part":1.0}, 2020-06-03 18:27:06.565191
{"id":12,"title":"Chemistry","part":2.0},
{"id":13,"title":"Biology","part":3.0}]
Update
This library does not support json[] type because it could be rather redundant.
The example below uses plain JDBC + ObjectMapper to handle specific PostgreSQL array of json
Main point is that you need to use getArray method of ResultSet and then convert the String values inside PGobject to your object
ConfigurableEnvironment environment = (ConfigurableEnvironment) applicationContext.getEnvironment();
DataSource ds = DataSourceBuilder.create()
.username(environment.getProperty("ds.pgsql.username"))
.password(environment.getProperty("ds.pgsql.password"))
.url(environment.getProperty("ds.pgsql.url")).build();
try (Connection connection = ds.getConnection();
PreparedStatement ps = connection.prepareStatement("SELECT id, lessons FROM lesson");
ResultSet rs = ps.executeQuery()) {
while (rs.next()) {
int id = rs.getInt("id");
Object[] arrLessons = (Object[]) rs.getArray("lessons").getArray();
List<Lesson> jsonLessons = Arrays.stream(arrLessons)
.map(PGobject.class::cast)
.map(lesson -> convert(lesson.getValue()))
.collect(Collectors.toList());
System.out.println(id + "; converted: " + jsonLessons);
}
}
//...
private Lesson convert(String value) {
try {
return mapper.readValue(value, Lesson.class);
} catch (JsonProcessingException e) {
throw new IllegalArgumentException(e);
}
}
Output
1; converted: [Lesson(id=1, title=Math, part=0.0), Lesson(id=2, title=English, part=0.0)]
2; converted: [Lesson(id=3, title=Physics, part=0.0), Lesson(id=4, title=Chemistry, part=0.0)]

Java Spring JPA magical update

I am having two Entities:
Aircraft
import javax.persistence.Entity;
import javax.persistence.ManyToOne;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.jpa.domain.AbstractPersistable;
#Entity
#Data
#NoArgsConstructor
#AllArgsConstructor
//#ToString
public class Aircraft extends AbstractPersistable<Long> {
private String name;
#ManyToOne
private Airport airport;
#Override
public String toString(){
return name;
}
}
And Airport:
public class Airport extends AbstractPersistable<Long> {
private String identifier;
private String name;
#OneToMany(mappedBy = "airport")
private List<Aircraft> aircrafts = new ArrayList<>();
#Override
public String toString(){
String aircraftString = aircrafts.stream().map(r -> r.toString()).collect(Collectors.joining(", "));
return "airport " + name + " " + "[" + aircraftString + "]";
}
}
And a #PostMapping in #Controller like this:
#PostMapping("/aircrafts/{aircraftId}/airports")
public String assignAirport(#RequestParam Long airportId,#PathVariable Long aircraftId){
Aircraft aircraft = aircraftRepository.getOne(aircraftId);
Airport airport = airportRepository.getOne(airportId);
aircraft.setAirport(airport);
aircraftRepository.save(aircraft)
System.out.println(airport.toString());
System.out.println(aircraft.toString());
return "redirect:/aircrafts";
}
This works. But I can not figure out how does this
private List<Aircraft> aircrafts = new ArrayList<>();
List get updated?
I first figured it should work like this in #Controller
airport.getAircrafts().add(aircraft);
But that does not do anything.

The OneToMany relation in the airport class only reflecting what is persisted in the ManyToOne relation in the aircraft class so whenever you will add a new plane that has an airport, this airport planes List will be updated.
Side Note:
If you want to achieve the behavior you were expecting you can add
#OneToMany(mappedBy = "airport", cascade = CascadeType.ALL)
private List<Aircraft> aircrafts = new ArrayList<>();
public void addAircraft(Aircraft aircraft){
aircraft.setAirport(this);
aircrafts.add(aircraft);
}
to your airport class and then save the airport entity.
but I think this isn't what you want and also it's not beneficial in your current case

spring JPA incrementally save an entity

I am trying to persist an entity incrementally.
Here is an overview of the Entity class
package aop.web.teacher.rmodels;
// Generated 11 Feb, 2011 3:57:41 PM by Hibernate Tools 3.2.2.GA
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import org.hibernate.validator.constraints.NotEmpty;
/**
* AopTeacherMaster generated by hbm2java
*/
#Entity
#Table(name="aop_teacher_master"
,schema="public"
)
public class AopTeacherMaster implements java.io.Serializable {
private long id;
private AopTeachersDistrictMaster aopTeachersDistrictMasterByCurrDistrict;
private AopInstitutionmaster aopInstitutionmaster;
private AopTeachersDistrictMaster aopTeachersDistrictMasterByPermDistrict;
#NotEmpty(message="Fathers name is mandatory")
private String fathersName;
#NotEmpty
private String currAddLine1;
private String currAddLine21;
private String currAddLine22;
private String currAddLine3;
private String currDevelopmentBlock;
private String currPoliceStation;
private String currCity;
private String currPin;
private String currState;
private String currCountry;
private String permAddLine1;
private String permAddLine21;
private String permAddLine22;
private String permAddLine3;
private String permDevelopmentBlock;
private String permPoliceStation;
private String permCity;
private String permPin;
private String permState;
private String permCountry;
private Date dateOfBirth;
private Character gender;
private Character maritalStatus;
private String religion;
private String caste;
private String landLineNumber;
private String mobileNumber;
private String email;
private String uidNum;
private String bankName;
private String bankBranch;
private String bankAccountNum;
private String gpfNum;
private Set aopTeachersSanctionedPostDetailsForCurrentIncumbentId = new HashSet(0);
private Set aopTeachersSanctionedPostDetailsForFirstIncumbentId = new HashSet(0);
public AopTeacherMaster() {
}
public AopTeacherMaster(long id) {
this.id = id;
}
Now I have a 2 step wizard like process where in the first screen
user enters some of the properties of the entity and the entity gets merged,
In the second step additional or rest of the properties are filled.
I am using spring 3 annotation based controller where I am using the entity class
as the command object.
On the first go entity gets saved with screen one values then I am sending the
reference from merge as command object for second screen.
However, second screen seems to populate the entries there but nullifies the
existing properties which were from the first screen.
Here is the controller code for the same
#RequestMapping(value = "/insertteacher.html", method = RequestMethod.POST)
public
String testEm(#Valid AopTeacherMaster teacher, BindingResult result,
Map model) {
logger.info("Checking Teacher for error");
if (result.hasErrors()) {
logger.info("User data has:" + result.getErrorCount() + " errors!");
// ////////////////////
for (Object object : result.getAllErrors()) {
if (object instanceof FieldError) {
FieldError fieldError = (FieldError) object;
logger.error("Error on field::" + fieldError.getField()
+ " || error type ::" + fieldError.getCode());
}
}
model.put("smessage", "There was an error");
return "teachersmasterInsert";
}
logger.info("Attemped saving!");
teacher=schoolMasterService.add(teacher);//recieved the reference after merge! Will be used for command object in the next screen
model.put("teacher", teacher);//This is the command object for second screen
model.put("smessage", "teacher inserted successfully");
return "teachersmasterInsert2";
// List myList=testDaoService.findAllTeachers();
// for(Teachermaster t:myList){logger.info("Got::"+t.getId());}
}
#RequestMapping(value = "/insertteacher2.html", method = RequestMethod.POST)
public
String testEm2(#Valid AopTeacherMaster teacher, BindingResult result,
Map model) {
logger.info("Checking Teacher for error second insert");
if (result.hasErrors()) {
logger.info("User data has:" + result.getErrorCount() + " errors!");
// ////////////////////
for (Object object : result.getAllErrors()) {
if (object instanceof FieldError) {
FieldError fieldError = (FieldError) object;
logger.error("Error on field::" + fieldError.getField()
+ " || error type ::" + fieldError.getCode());
}
}
model.put("smessage", "There was an error");
return "teachersmasterInsert";
}
logger.info("Attemped saving!");
teacher=schoolMasterService.add(teacher);
model.put("teacher", teacher);
model.put("smessage", "teacher second instance inserted successfully");
return "teachersmasterInsert";
// List myList=testDaoService.findAllTeachers();
// for(Teachermaster t:myList){logger.info("Got::"+t.getId());}
}
Is this the correct way to do it? Otherwise
how can I achieve this incremental save?
Please suggest!
thanks in advance.

The typical way to implement wizards in annotation based controller is to store partially constructed object in the session, and save it only after the last step:
#Controller
// Model attribute with name "aopTeacherMaster" is transparently stored in the session
#SessionAttribute("aopTeacherMaster")
public class TeacherController {
...
#RequestMapping(value = "/insertteacher2.html", method = RequestMethod.POST)
public String testEm2(#Valid AopTeacherMaster teacher, BindingResult result, Map model) {
...
// No need to save teacher here
}
#RequestMapping(value = "/insertteacherLast.html", method = RequestMethod.POST)
public String testEmLast(#Valid AopTeacherMaster teacher, BindingResult result,
Map model, SessionStatus status) {
...
// Save teacher at the last step
teacher=schoolMasterService.add(teacher);
// Remove it from the session
status.setComplete();
}
}
Alternatively, if you really need incremental save for some reason, you can load the current state of the entity from the database and copy fields with data from the model object manually.