Using Comparable To Compare and sort TreeSet in Descending Of JPA Entity Id

2022-05-04 10:22 user3462941 imported from Stackoverflow

I am trying to sort my TreeSet using JPA Auto Generated Id. Here, Note is an Entity class.

@Entity
@Table(name="NOTE")
@Getter
@Setter
public class Note implements Comparable<Note> {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;
    private String note;
    @ManyToOne
    @JoinColumn(name = "noteDetailsId")
    private NoteDetails noteDetails;
     
   @override
   public int compareTo(Note myNote) {
   return myNote.getId().intValue() - this.getId().intValue();
  }
   
}

@Entity
@Table(name="NOTE_DETAILS")
@Getter
@Setter

class NoteDetails  {
  @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;
@OneToMany(mappedBy = "noteOperation", cascade = Cascadetype.ALL, orphanRemoval = true, fetch=fetchType.EAGER)
private Set<Note> notes = new TreeSet<>();

public void addNote(String note) {
   this.notes.add(new Note().setNote("note1"));
}

}

My problem is that, I am getting JPA Ids as null in compareTo() method. Hence thowing nullPointerException. My purpose is to sort TreeSet in descending order of JPA Ids. But those Ids are coming null.

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I have a file that has student names, age, and an id number. I have a student class that holds the everything above for each student object. I stored all the names, id numbers. and age separately in an array list. Now im trying to assign the info to create a student object.

public class Student {
    private String lName;
    private int idNumber;
    private int age;

    public Student() {
        lName = "";
        idNumber = 0;
        age = 0;
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My Text File looks something like this: This info is stored in parallel array lists. I don't quite get how to implement this into an object to pass it into my second contractor method.

  Josh          2134         19
  Smith         5256         21
  Rogers        9248         19
  Andrew        7742         20

Here's what I've tried;

public static void main(String[] args) {
    String file = "studentData.txt";
    Scanner reader = new Scanner(file);

    ArrayList<String> lastNames = lNames(file);
    ArrayList<Integer> idNumbers = idNum(file);
    ArrayList<Integer> ageList = ages(file);

    Scanner input = new Scanner(System.in);

    Student s1 = new Student();

    // confused about how to implement this constructor with the textile info
    for (int i = 0; i<idNumbers.size(); i++) {
        Student user = new Student(lastNames.get(i), idNumbers.get(i), ageList.get(i));
    }

    //user enters idNumber to display age
    System.out.println("Enter ID Number"); //exception handling to be added
    int idNum = input.nextInt();

    for (int i = 0; i<idNumbers.size(); i++) {
        if (idNum == idNumbers.get(i)) {
            s1.setAge(ageList.get(i));
            System.out.println(s1.getAge());

        }
    }
}

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I have recycleview xml in my project with in many sub cardview layouts(which is scrollable) and I want to create item in the bottom nav which is called "Goto". When the "Goto" item is clicked i want it to pop-up like the screenshot. And when user enters a number(according to the cardviews i.e if the number of cardview is 40 user must enter 1-40) I want to search the cardview by its ID. Thank you and I hope u got it, If u have any questions let me know [1]: https://i.stack.imgur.com/grK8P.jpg

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 <LinearLayout>
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<LinearLayout>
  <androidx.cardview.widget.CardView>
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  <LinearLayout>
  <androidx.cardview.widget.CardView>
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 </androidx.cardview.widget.CardView>
 </LinearLayout>
 
  ..
  ..

  ..
  ..
  many more..
```
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I'm having a big problem that a few rows of the table are not returning by the native query of hibernate (Spring Data), although if I put the same query in the database it returns. No exceptions or warnings appear in the log. My database is MySQL.

Follows the query:

    @Query(value = "SELECT MID(UUID(),1,36) as unique_key, " +
        "TRIM(avio_sinr.num_sinr) as num_sinr, " +
        "avio_sinr.dat_alte_regc, " +
        "avio_sinr.dat_cria_sinr, " +
        "avio_sinr.vlr_limi_inde, " +
        "avio_sinr.vlr_pgto_sinr, " +
        "TRIM(avio_sinr.cod_apol_prco) as cod_apol_prco, " +
        "ctto_usua_prco.nom_emai_usua_prco, " +
        "ctto_usua_prco.num_cell_usua_prco, " +
        "ctto_usua_prco.cod_ddi_tel_usua_prco, " +
        "ctto_usua_prco.cod_ddd_tel_usua_prco, " +
        "ctto_usua_prco.cod_ddi_cell_usua_prco, " +
        "ctto_usua_prco.cod_ddd_cell_usua_prco, " +
        "dado_pgto.bco, " +
        "dado_pgto.cod_tipo_cont_bace, " +
        "dado_pgto.agencia, " +
        "dado_pgto.num_cont_clie, " +
        "dado_pgto.num_digt_verf, " +
        "ende_prco.id_cep_logr, " +
        "ende_prco.nom_bair_usua_prco, " +
        "ende_prco.nom_cida_usua_prco, " +
        "ende_prco.nom_logr_usua_prco, " +
        "ende_prco.num_ende_usua_prco, " +
        "ende_prco.sg_uf, " +
        "ende_prco.txt_cmpl_usua_prco, " +
        "even_ocro.cod_ramo_sega, " +
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        "gara_disi.cod_gara_sinr, " +
        "gara_disi.cod_cobt, " +
        "gara_disi.cod_prod_segu, " +
        "gara_disi.des_gara_sinr, " +
        "gara_disi.nom_gara_sinr, " +
        "prco_abet_sinr.num_prco_sinr, " +
        "prco_abet_sinr.dat_hor_abet_prco, " +
        "prco_abet_sinr.dat_ocor_sinr, " +
        "prco_abet_sinr.hor_ocor_sinr, " +
        "prco_abet_sinr.num_funl_cola_cogl, " +
        "prco_abet_sinr.num_funl_rspl_regc, " +
        "prco_abet_sinr.txt_ocor_sinr, " +
        "situ_prco.nom_situ_prco, " +
        "situ_sinr.nom_situ_sinr, " +
        "tipo_rela_solt_benf.cod_tipo_rela, " +
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        "LEFT JOIN gara_disi gara_disi ON (avio_sinr.cod_gara_sinr = gara_disi.cod_gara_sinr) " +
        "LEFT JOIN tipo_rela_solt_benf tipo_rela_solt_benf ON (usua_prco.cod_tipo_rela = tipo_rela_solt_benf.cod_tipo_rela) " +
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        "LEFT JOIN decs_avio_sinr decs_avio_sinr ON (avio_sinr.num_sinr = decs_avio_sinr.num_sinr) " +
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List<MovimentacaoSinistroEntity> findByProtocoloSinistroPaginacao(Long limit, Long offset);

Follows the class:

@Entity
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class MovSiEntity {

    @EmbeddedId
    private MovPK movSiPK;

    @Column(name = "num_sinr")
    private String numberSi;

    @Column(name = "cod_gara_sinr")
    private Integer codeWarrantSi;

    @Column(name = "dat_alte_regc")
    private LocalDate dateAlteracaoRegistroSi;

    @Column(name = "dat_cria_sinr")
    private LocalDateTime dateCriacaoSi;

    @Column(name = "vlr_limi_inde")
    private BigDecimal valueLimiteIndenizacaoSi;

    @Column(name = "vlr_pgto_sinr")
    private BigDecimal valuePagamentoSi;

    @Column(name = "dat_hor_abet_prco")
    private LocalDateTime dateOpenProtocol;

    @Column(name = "dat_ocor_sinr")
    private LocalDate dateOcorrenciaSi;

    @Column(name = "hor_ocor_sinr")
    private Time hourOcorrenciaSi;

    @Column(name = "vlr_ofrt_clie")
    private BigDecimal valueOfferClient;

    @Column(name = "dat_hor_decs")
    private LocalDateTime dateHourdecision;

    @Column(name = "nom_emai_usua_prco")
    private String emailUserProtocol;

    @Column(name = "cod_ddi_tel_usua_prco")
    private Short codeDdiTelUserProtocol;

    @Column(name = "cod_ddd_tel_usua_prco")
    private Short codeDddTelUserProtocol;

    @Column(name = "cod_ddi_cell_usua_prco")
    private Short codeDdiCelUserProtocol;

    @Column(name = "cod_ddd_cell_usua_prco")
    private Short codeDddCelUserProtocol;

    @Column(name = "bco")
    private String codeBanco;

    @Column(name = "cod_tipo_cont_bace")
    private String codeTipoAccountBacen;

    @Column(name = "agencia")
    private String agencia;

    @Column(name = "num_cont_clie")
    private String numberAccountClient;

    @Column(name = "num_digt_verf")
    private String numberDigitoVerify;

    @Column(name = "id_cep_logr")
    private String cepplace;

    @Column(name = "nom_bair_usua_prco")
    private String bairroUserProtocol;

    @Column(name = "nom_cida_usua_prco")
    private String cidadeUserProtocol;

    @Column(name = "nom_logr_usua_prco")
    private String placeUserProtocol;

    @Column(name = "sg_uf")
    private String siglaUnidadeFederacao;

    @Column(name = "txt_cmpl_usua_prco")
    private String complementoplaceUserProtocol;

    @Column(name = "nom_even_infd")
    private String nomeEventoInformado;

    @Column(name = "des_gara_sinr")
    private String descWarrant;

    @Column(name = "nom_gara_sinr")
    private String nomeWarrant;

    @Column(name = "num_funl_cola_cogl")
    private String funcionalColaboradorConglomerado;

    @Column(name = "num_funl_rspl_regc")
    private String funcionalResponsavelRegulacao;

    @Column(name = "txt_ocor_sinr")
    private String textoOcorrenciaSi;

    @Column(name = "des_tipo_rela")
    private String descriptionTipoRelacao;

    @Column(name = "nom_tipo_rela")
    private String nomeTipoRelacao;

    @Column(name = "cod_sexo")
    private String codeSexo;

    @Column(name = "cod_tipo_pess")
    private String codeTipoPessoa;

    @Column(name = "nom_cpto_usua_prco")
    private String nomeCompletoUserProtocol;

    @Column(name = "num_cpf_cnpj_usua_prco")
    private String numberCpfCnpjUserProtocol;

    @Column(name = "num_cell_usua_prco")
    private Integer numberCelularUserProtocol;

    @Column(name = "num_ende_usua_prco")
    private Integer numberEnderecoUserProtocol;

    @Column(name = "cod_ramo_sega")
    private Integer codeRamoSeguradora;

    @Column(name = "cod_tipo_rela")
    private Integer codeTipoRelacao;

    @Column(name = "cod_cobt")
    private Integer codeCobertura;

    @Column(name = "cod_prod_segu")
    private Integer codeProdutoSeguro;

    @Column(name = "nom_situ_prco")
    private String nomeSituacaoProtocol;

    @Column(name = "nom_situ_sinr")
    private String nomeSituacaoSi;

    @Column(name = "txt_decs_anai")
    private String decisionAnalista;


}

follows the Embeddable class:

@Embeddable
@Getter
@Setter
@Builder
@EqualsAndHashCode
@AllArgsConstructor
@NoArgsConstructor
public class MovSiPK  implements Serializable {

    @Column(name = "unique_key")
    private String uniqueKey;

    @Column(name = "num_prco_sinr", nullable = false)
    private String numberProtocolSi;

    @Column(name = "cod_apol_prco")
    private String codeApoliceProtocol;


}

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    else if ((exp == o.exp) || (fraction - o.fraction > SMALL))
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}
```
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    else
        System.out.println("error");
}
```
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I am trying to solve a problem wherein I am given a bunch of days and some jobs to do within those days. Each job has a day deadline before which it has to be finished. As such, when I am assigning jobs to days I can assign the particular job to any day on or before its deadline. I can do this by maintaining an array of days and checking which day is available from deadline going back to day 1 (will have to do this for each job). Hence this method would take up O(N^2) time. However if I can use something like a TreeSet in Java which returns the floor value of a searched day (so if I search for day 5 but it already has a job assigned to it and the next free day is day 3, TreeSet.floor(5) returns 3), that would take up only log N time for the search part reducing it to an O(N log N) operation.

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I know that TreeSet in Java sort its elements in ascending order. For integer it would be 1, 2, 3, 4, 5, for String it would be alphabetical. However, what if I want to input objects in that TreeSet, how it is going to be sorted by default?

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Using Comparable To Compare and sort TreeSet in Descending Of JPA Entity Id

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