通过Java中的用户请求从数组中删除/读取特定元素

Question

Can someone tell me whats wrong with my public Employee deleteEmployeeID and my public Employee readEmployeeID methods. The user should be able to delete or read more information about a specific employee ID they request. I can't seem to find whats wrong with my two methods.

SubClass

package WorkIDServerStorage;

public class EmployeeList{
    private Employee[] theEmployee;
    private int arrayEmployee;

    public EmployeeList(){
        theEmployee = new Employee[100];
        arrayEmployee = 0;
    }

    public EmployeeList(int arraySize){
        theEmployee = new Employee[arraySize];
        arrayEmployee = 0;
    }

    public void setTheEmployee(Employee[] inputTheEmployee){
        theEmployee = inputTheEmployee;
    }

    public void setArrayEmployee(int inputArrayEmployee){
        arrayEmployee = inputArrayEmployee;
    }

    public Employee[] getTheEmployee(){
        return theEmployee;
    }

    public int getArrayEmployee(){
        return arrayEmployee;
    }

    public Employee addEmployeeID(Employee employeeAdd){
        return theEmployee[arrayEmployee++] = employeeAdd;
    }

    public Employee deleteEmployeeID(int employeeDelete){        
        for(int i = employeeDelete + 1; i < theEmployee.length; i++){
            theEmployee[i-1] = theEmployee[i];
        }
        return null;
    }

    public Employee readEmployeeInfo(int employeeRead){
        return theEmployee[employeeRead];
    }

    @Override
    public String toString(){
        StringBuilder sb = new StringBuilder();
        for(int x = 0; x < arrayEmployee; x++){
            sb.append(theEmployee[x].toString()).append("\n");
        }return sb.toString();
    }
}

Main Class

package WorkIDServerStorage;
import java.util.Scanner;

public class EmployeeListTest{
    public static void main(String[] args){
        EmployeeList EmployeeListObject = new EmployeeList();
        Scanner input = new Scanner(System.in);

        System.out.println("► Initiating Employee Information Server Storage ◄");
        System.out.println("► Type 'EXIT' at any moment to close the program ◄\n");

        for(int x = 1; x < 6; x++){
            Employee EmployeeObject = new Employee("Employee " + x, 1234 + x, 15 + x);
            EmployeeListObject.addEmployeeID(EmployeeObject);
        }
        System.out.println(EmployeeListObject);

        System.out.print("\nType 'ADD' to add a new employee\n");
        System.out.print("Type 'DELETE' to delete an employee record\n");
        System.out.print("Type 'READ' to read the data of an employee ");
        String menuOption = input.next();

        if(menuOption.equalsIgnoreCase("EXIT")){
            EmployeeListObject.toString();
        }else if(menuOption.equalsIgnoreCase("ADD")){
            System.out.print("\nInsert employee ID: ");
            String addEmployeeID = input.next();
            EmployeeListObject.addEmployeeID(addEmployeeID);
        }else if(menuOption.equalsIgnoreCase("DELETE")){
            System.out.print("\nInsert employee ID: ");
            String deleteEmployeeID = input.next();
            EmployeeListObject.deleteEmployeeID(deleteEmployeeID);
        }else if(menuOption.equalsIgnoreCase("READ")){
            System.out.print("\nInsert employee ID: ");
            String readEmployeeID = input.next();
            EmployeeListObject.readEmployeeInfo(readEmployeeID);
        }      
    }
}

Answer 1

The main issue I see, which may or may not be the cause of your problem is in your main class. Observe how when the user asks to Read data, nothing is ever actually printed into the console.

The line

EmployeeListObject.readEmployeeInfo(readEmployeeID);

Calls the method

public Employee readEmployeeInfo(int employeeRead){
    return theEmployee[employeeRead];
}

Which just returns and Employee object but never prints anything. Therefore the user will never be able to read employee data.

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The other issue in your code is what @popiandro commented. However I do not think it is the one causing your program to break.

public Employee deleteEmployeeID(int employeeDelete){        
    for(int i = employeeDelete + 1; i < theEmployee.length; i++){
        theEmployee[i-1] = theEmployee[i];
    }
    return null;
}

This method will always return null , and there is no point in doing that. Set the method to void .

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