I have 2 Entities: Employee and Specialty.
Every Employee can have some Specialties.
POJOs are generated.
#Entity(indices = {#Index(value = {"f_name", "l_name", "birthday",
"avatarLink"}, unique = false)}, inheritSuperIndices = true)
public class Employee implements Serializable {
#PrimaryKey(autoGenerate = true)
private int employeeId;
private String f_name;
private String l_name;
private String birthday;
#Ignore
private int age;
private String avatarLink;
#Embedded
private List<Specialty> specialty;
private final static long serialVersionUID = -8824149947485321362L;
#Ignore
public Employee() {
}
public Employee(int employeeId, String f_name, String l_name, String
birthday, String avatarLink, List<Specialty> specialty) {
this.employeeId = employeeId;
this.f_name = f_name;
this.l_name = l_name;
this.birthday = birthday;
this.avatarLink = avatarLink;
this.specialty = specialty;
}
public int getEmployeeId() {
return employeeId;
}
public void setEmployeeId(int employeeId) {
this.employeeId = employeeId;
}
And some more setters\getters...
And Specialty
#Entity
public class Specialty implements Serializable {
#PrimaryKey
private int specId;
private String specName;
private final static long serialVersionUID = 4288061416169200241L;
public Specialty(int specId, String specName) {
this.specId = specId;
this.specName = specName;
}
#Ignore
public Specialty() {
}
public int getSpecId() {
return specId;
}
And some more setters\getters...
I have this error:
error: Entities and Pojos must have a usable public constructor. You can have an empty constructor or a constructor whose parameters match the fields (by name and type).
I check so many questions and read docs, but it not helps me. Thank you
you should add #Ignore to serialVersionUID fields.
In view of Room, it's just another column.
#Ignore
private final static long serialVersionUID = 4288061416169200241L;
Related
I have thought extensively about it and came up with these 2 classes:
public class Drone {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#NotEmpty(message = "Serial Number is required")
#Size(max = 100)
private String serial_number;
private ModelType model;
#Max(500)
private int weight_limit;
#NotEmpty(message = "Battery capacity is required")
private BigDecimal battery_capacity;
private StateType state;
}
and
public class Medication {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Pattern(regexp = "^[a-zA-Z0-9_-]*$")
private String name;
private float weight;
#Pattern(regexp = "^[a-zA-Z0-9_]*$")
private String code;
#Column(nullable = true, length = 64)
private String image;
}
But I just can't figure out how to link them since each drone will be carrying medications. I still think I'm missing something. Any ideas?
I was trying to add data to my tableView in my JavaFX app. I am using hibernate to do operations on my Database. I used a query to get all the orders and store each order in an object and added the object to the observable list of the tableView. I created the orders class and mapped it to my database. This is the class of the orders:
#Entity
#Table(name = "orders")
public class orders implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "order_id")
private int order_id;
#JoinColumn(name = "item_id")
#ManyToOne
#NotNull
private items item_id;
#Column(name = "quantity")
#NotNull
private int quantity;
#Column(name = "price_per_unit")
#NotNull
private double price_per_unit;
#Column(name = "total_price")
#NotNull
private double total_price;
#Column(name = "order_date")
#NotNull
private Date order_date;
#JoinColumn(name = "user_id")
#ManyToOne
#NotNull
private users user_id;
public orders() {
}
public orders(int order_id, items item_id, int quantity, double price_per_unit, double total_price, Date order_date, users user_id) {
this.order_id = order_id;
this.item_id = item_id;
this.quantity = quantity;
this.price_per_unit = price_per_unit;
this.total_price = total_price;
this.order_date = order_date;
this.user_id = user_id;
}
public int getOrder_id() {
return order_id;
}
public void setOrder_id(int order_id) {
this.order_id = order_id;
}
public items getItem_id() {
return item_id;
}
public void setItem_id(items item_id) {
this.item_id = item_id;
}
public int getQuantity() {
return quantity;
}
public void setQuantity(int quantity) {
this.quantity = quantity;
}
public double getPrice_per_unit() {
return price_per_unit;
}
public void setPrice_per_unit(double price_per_unit) {
this.price_per_unit = price_per_unit;
}
public double getTotal_price() {
return total_price;
}
public void setTotal_price(double total_price) {
this.total_price = total_price;
}
public Date getOrder_date() {
return order_date;
}
public void setOrder_date(Date order_date) {
this.order_date = order_date;
}
public users getUser_id() {
return user_id;
}
public void setUser_id(users user_id) {
this.user_id = user_id;
}
}
And the below code is the code of the view in which I have the tableView that loads the orders and displays the orders from the database:
public class OrdersPageController implements Initializable {
private Main app;
private Session session;
private Transaction transaction = null;
#FXML
private TableView<orders> table;
public void setApp(Main app) {
this.app = app;
}
/**
* Initializes the controller class.
*/
#Override
public void initialize(URL url, ResourceBundle rb) {
session = HibernateUtil.getSessionFactory().openSession();
transaction = session.beginTransaction();
//Fill the table view
getOrders();
}
public void goBack(ActionEvent event){
session.close();
transaction = null;
app.goToHomePage();
}
public void processLogout(ActionEvent event){
session.close();
transaction = null;
app.userLogout();
}
public void addOrder(ActionEvent event){
session.close();
transaction = null;
app.addOrdersPage();
}
public void deleteOrder(ActionEvent event){
session.close();
transaction = null;
app.closeOrdersPage();
}
public void getOrders(){
try{
String hql = "FROM orders";
Query query = session.createQuery(hql);
List<orders> list = query.getResultList();
for (orders o : list) {
//Create an order object
orders order = new orders();
order.setOrder_id(o.getOrder_id());
order.setItem_id(o.getItem_id());
order.setPrice_per_unit(o.getPrice_per_unit());
order.setQuantity(o.getQuantity());
order.setOrder_date(o.getOrder_date());
order.setTotal_price(o.getTotal_price());
order.setUser_id(o.getUser_id());
//Create an observable list for the table
ObservableList<orders> tableList = table.getItems();
//Add the order object to the list
tableList.add(order);
//Set the created list to the table to show data
table.setItems(tableList);
}
}catch(Exception e){
System.out.println(e.getMessage());
}
finally{
session.close();
}
}
}
Note that the getOrders method is the method that gets the orders from the database and sets the observable list of the tableView.
I am having problem displaying the item_id and the user_id of the order. I think the problem is that they both are objects of type items and users respectively and the table displays the address of the objects. Instead I want to display the numbers of the ids of the item ordered and the user that made the order. If you know what I can do to fix my problem please share it with me.
Add cellFactorys to the relevant columns. You haven't shown the FXML in the question, so I don't know the names you assigned to the appropriate TableColumn instances, but you can do something like this:
public class OrdersPageController implements Initializable {
// ...
#FXML
private TableView<orders> table;
#FXML
private TableColumn<orders, users> userColumn ;
#Override
public void initialize(URL url, ResourceBundle rb) {
userColumn.setCellFactory(tc -> new TableCell<>() {
#Override
protected void updateItem(users user, boolean empty) {
super.updateItem(user, empty);
if (empty || user == null) {
setText("");
} else {
String text = /* anything you need based on user */
setText(text);
}
}
});
session = HibernateUtil.getSessionFactory().openSession();
transaction = session.beginTransaction();
//Fill the table view
getOrders();
}
}
Just override toString method in users and items Classes:
Example: in your users Class ->
#Override
public String toString() {
return user_id.toString();
}
As James_D stated, have a look on java conventions. Java Classes should be always be with Capital Letter.
I am trying to achieve many-to-many relationship in Room Persistence Library. I am trying to create a Notes App with Tags.
The idea is:
A note will have multiple tags.
A tag will have multiple notes.
Show all notes in RecyclerView along with Tags.
To achieve this, I have created two models Note.java, Tag.java and TagJoin model to store the relationship b/w notes and tags. Achieving one-to-one is very easy using #Relation annotation.
Here are my models
#Entity(tableName = "notes")
public class Note {
#PrimaryKey
#NonNull
public final String id;
#ColumnInfo(name = "note")
public String note;
#Ignore
public List<Tag> tags;
#Ignore
public Note(String note) {
this(UUID.randomUUID().toString(), note);
}
public Note(String id, String note) {
this.id = id;
this.note = note;
}
public String getId() {
return id;
}
public String getNote() {
return note;
}
public void setNote(String note) {
this.note = note;
}
public List<Tag> getTags() {
return tags;
}
public void setTags(List<Tag> tags) {
this.tags = tags;
}
#Entity(tableName = "note_tag_join",
primaryKeys = {"noteId", "tagId"},
foreignKeys = {
#ForeignKey(
entity = Note.class,
parentColumns = "id",
childColumns = "noteId",
onDelete = CASCADE),
#ForeignKey(
entity = Tag.class,
parentColumns = "id",
childColumns = "tagId",
onDelete = CASCADE)},
indices = {
#Index(value = "noteId"),
#Index(value = "tagId")
}
)
public static class TagJoin {
#NonNull
public final String noteId;
#NonNull
public final String tagId;
public TagJoin(String noteId, String tagId) {
this.noteId = noteId;
this.tagId = tagId;
}
}
}
Tags Model:
#Entity(tableName = "tags", indices = {#Index(value = "name", unique = true)})
public class Tag {
#PrimaryKey
#NonNull
public String id;
#ColumnInfo(name = "name")
public String name;
#Ignore
public Tag(String name) {
this(UUID.randomUUID().toString(), name);
}
public Tag(String id, String name) {
this.id = id;
this.name = name;
}
public String getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
Notes Dao:
#Dao
public interface NoteDao {
#Query("SELECT * FROM notes ORDER BY id DESC")
LiveData<List<Note>> getAllNotes();
#Insert
long insert(Note note);
#Update
void update(Note note);
#Delete
void delete(Note note);
#Query("DELETE FROM notes")
void deleteAll();
#Query("SELECT COUNT(*) FROM notes")
int getNotesCount();
#Query("SELECT notes.* FROM notes\n" +
"INNER JOIN note_tag_join ON notes.id=note_tag_join.noteId\n" +
"WHERE note_tag_join.tagId=:tagId")
List<Note> getAllNotesOfTag(String tagId);
#Insert
void insert(Note.TagJoin... joins);
#Delete
void delete(Note.TagJoin... joins);
}
So far everything is good. Now I want to show the Notes in RecyclerView but I can't find a way to fetch all Notes along with Tags at once. One way is, getting the tags of each note in onBindViewHolder method which I think is wrong as we have to query the db each time row is displayed.
Please provide me suggestions.
PS: I have followed the code provided in this article
https://commonsware.com/AndroidArch/previews/mn-relations-in-room
I have two classes related by ManyToOne, I have the id of "Chantier" and I'd like to find all the Lots which have this chantier's id.
public class Chantier implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String titre_aff;
private String num_aff;
private String ville;
public class Lots implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
List<String> numero_lot;
List<String> designation;
#ManyToOne
private Chantier chantier;
I tried with this in my LotsREST but it is looking for Lots with this id and not chantier :
#GET
#Path("{id}")
#Produces(MediaType.APPLICATION_JSON)
public Lots getLotByChantier(#PathParam("id") String id) {
return faL.find(Long.parseLong(id));
}
I just created this function to return what i wanted
#GET
#Path("{id}")
#Produces(MediaType.APPLICATION_JSON)
public List<Lots> getLotByChantier(#PathParam("id") String id) {
List<Lots> listLots = faL.findAll();
for (Lots lot : listLots) {
if (!lot.getChantier().getId().equals(Long.parseLong(id))) {
listLots.remove(lot);
}
}
return listLots;
}
I am trying to get the user's friends list from Facebook.
The problem seems to be the Javabean...
FBUser fbuser = new Gson().fromJson(jsonStr, FBUser.class);
public class FBUser implements Serializable {
private static final long serialVersionUID = -3154429420153433117L;
private String id;
private String name;
private String email;
private Friends friendsList = new Friends();
private FBUser() { }
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public List<Data> getFriendsList() {
return friendsList.getData();
}
public static class Friends implements Serializable {
private static final long serialVersionUID = 6991758772193514527L;
private List<Data> data;
private Friends() { }
public List<Data> getData() {
return data;
}
public void setData(List<Data> data) {
this.data = data;
}
public class Paging implements Serializable {
private static final long serialVersionUID = 1689816298710621080L;
private String next;
private Paging() { }
public String getNext() {
return next;
}
public void setNext(String next) {
this.next = next;
}
}
}
public class Data implements Serializable {
private static final long serialVersionUID = -5008541658519841090L;
private String id;
private String name;
private Data() { }
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
}
Json:
json: {"id":"10861234","name":"Whatever","email":"whatever\u0040gmail.com","friends":{"data":[{"name":"Someone","id":"10861234"},{"name" ...43"}],"paging":{"next":"https:\/\/graph.facebook.com\/10861234\/friends..."}}}
The fields ID, Name and Email I can retrieve succesfully... but the friendsList is null... =(
Maybe it is the way I am trying to get it from the nested class, any suggestions on that?
There is no friendsList in your JSON (or, there's no friends in your Java class - whichever way you'd like to look at it). Gson silently ignores anything in the JSON that is not present in your classes.
You have a field friends whose value is an object. That object has a field data which is an array of objects and a field paging which is another object.
You need to write Java classes that match that structure. You're ... close.
In your FBUser class change:
private Friends friendsList = new Friends();
to:
private Friends friends = new Friends();
or:
#SerializedName("friends")
private Friends friendsList = new Friends();
Then in your Friends class you need to add:
private Paging paging = new Paging();
Also note that you don't have to initialize these values unless you specifically don't want them to be non-null when using these classes elsewhere.