如何验证我是否将属性添加到相等的列表中？

Question

import entidades.*;

public class Main {

    public static void main(String[] args) {
        Profissional prof = new Profissional(null, null);
        List<Profissional> profissional = new ArrayList<Profissional>();
        Scanner sc = new Scanner(System.in);
        boolean loop = true;
        while(loop == true) {
            String comando = sc.next().toUpperCase();

            if (comando.contentEquals("RP")) {
                String nomePro = sc.nextLine();
                String categoriaPro = sc.nextLine();
                prof.NomeVerificacao(profissional, nomePro, categoriaPro);
            }
            if(comando.contentEquals("SAIR")) {
                break;
            }
        }

        for(Profissional pro : profissional) {
            System.out.println(pro);

This is my Main, it's running fine but i don´t think it is adding the atributes to the list and not verifying either.

i want to add the atributes to a list so i can create different objets but they can not have at least the name equal.

public class Profissional {
    private String nome;
    private String categoria;

    public Profissional(String nome, String categoria) {
        this.nome = nome;
        this.categoria = categoria;
    }


        public void NomeVerificacao(List<Profissional> profissional ,String nome, String categoria) {
        if(profissional.isEmpty() == true) {
            profissional.add(new Profissional(nome, categoria));
        }else {
            for(Profissional pro : profissional) {
                if(pro.nome.contentEquals(nome)) {
                    System.out.println("Já Exite esse nome");

                }else {
                    profissional.add(new Profissional(nome, categoria));    
                }
            }
        }
    }

    @Override
    public String toString() {
        return "nome=" + nome + ", categoria=" + categoria;
    }


}

this is the Profissional Class.

I'm almost there i think but the output keeps saying that the name exists even though it is the first name i'm inserting.

Answer 1

I ran your code on my machine and made 3 changes into it, and it's working for me now,

1)

String nomePro = sc.next(); String categoriaPro = sc.next();

2) In professional class just changed this function a bit:

public void NomeVerificacao(List<Profissional> profissional, String nome, String categoria) {
    if (profissional.isEmpty() == true) {
        profissional.add(new Profissional(nome, categoria));
    } else {
        int i = 0;
        for (; i < profissional.size(); i++) {
            if (profissional.get(i).nome.equals(nome)) {
                System.out.println("Já Exite esse nome");
                break;
            }
        }
        if (i == profissional.size()) {
            profissional.add(new Profissional(nome, categoria));
        }
    }
}

3) At the end of the class Main, wrote sc.close(); to close the scanner.

i/p and o/p : 
1) RP
   red
   color
2) RP
   orange
   color
3) RP
   orange
   paint
   Já Exite esse nome

4) SAIR
   nome=red, categoria=color
   nome=orange, categoria=color

As you can see in above i/p and o/p, nome=red and nome=orange with categoria=color are added in the list but when we tried to add the same nome=orange again but with different category as paint it didn't add it and printed the message "Já Exite esse nome". and after entering SAIR, the toString(); printed the list content at the end. So the message will be printed only if we try to add the object with the same name again int list (not the first or any other times).

Further optimizations are possible but for now, it will work!

Answer 2

package javaapplication8;

import java.lang.reflect.Constructor;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class JavaApplication8 {

    public static class Profissional {
        private String nome;
        private String categoria;

        public Profissional(String nome, String categoria) {
            this.nome = nome;
            this.categoria = categoria;
        }
    }

    public static void main(String[] args) {
        try {            
            List<Profissional> profissionalList= new ArrayList<>();

            Scanner sc = new Scanner(System.in);
            while(true) {

                System.out.print("\r\nEnter comando:");
                String comando = sc.next().toUpperCase();

                if (comando.contentEquals("RP")) {                
                    System.out.print("nome: ");              
                    String nome = sc.next();
                    sc.nextLine(); // wait enter

                    System.out.print("categoria: ");              
                    String categoria = sc.next();
                    sc.nextLine(); // wait enter

                    // access constructor of Profissional
                    Constructor profCtor =  Profissional.class.getConstructor(String.class, String.class);
                    profCtor.setAccessible(true);                        
                    // create instance of Profissional
                    Profissional newItem = (Profissional) profCtor.newInstance(nome, categoria);

                    // avoid duplicate nome in profissionalList
                    boolean isExist = false;
                    for(Profissional pro : profissionalList) {
                       if(pro != null){
                           if(pro.nome.toLowerCase().equals(newItem.nome.toLowerCase())){
                               isExist = true;
                               break;
                           }
                       }
                    }
                    if(!isExist){
                        profissionalList.add(newItem );
                    }
                }
                if(comando.contentEquals("SAIR")) {
                    break;
                }
            }

            for(Profissional pro : profissionalList) {
                if(pro != null) {
                    System.out.println("nome: " + pro.nome + " categoria: " + pro.categoria);
                }
            }
        }
        catch(Exception ex){
            System.out.println(ex.getMessage());             
        }
    }

}

Answer 3

I can propose the following solution:

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    // Set is a data structure that makes sure you don't have a duplicated elements
    // in this case we use TreeSet structure that accepts comparator which tells that
    // we need to compare elements only by professional's name
    Set<Profissional> profissionals = new TreeSet<>(Comparator.comparing(Profissional::getNome));

    while (true) {
        String comando = sc.next().toUpperCase();

        if (comando.contentEquals("RP")) {
            String nomePro = sc.next();
            String categoriaPro = sc.next();
            
            // add function returns true in case the element we're going to add
            // was not presented in Set structure yet. False otherwise.
            boolean isNew = profissionals.add(new Profissional(nomePro, categoriaPro));
            if (!isNew) {
                System.out.println("Professional with name " + nomePro + " already exists");
            } else {
                System.out.println("Professional with name " + nomePro + " was added");
            }
        } else if (comando.contentEquals("SAIR")) {
            break;
        }
    }
    
    // just prints all professionals at the end of the program
    profissionals.forEach(System.out::println);
}

public static class Profissional {

    private String nome;
    private String categoria;

    public Profissional(String nome, String categoria) {
        this.nome = nome;
        this.categoria = categoria;
    }

    // getters and setters

    @Override
    public String toString() {
        return "nome=" + nome + ", categoria=" + categoria;
    }
}

The output will be the following:

RP

test test

Professional with name test was added

RP

test1 test1

Professional with name test1 was added

RP

test test3

Professional with name test already exists

SAIR

nome=test, categoria=test

nome=test1, categoria=test1