Organizing array list of objects JAVA

Question

I'm having troubling organizing my list of employees. I just need to organize them according to their employee type (first two letters). Each object starts with the employee code which are the first two letters. This is what I need to separate the position types but for some reason I can't grab them.

Here is the file that I am creating the objects out of and storing them in the arrays.

PW_1234,James,Bond,01/02/10,1,10 PW_1235,John,Brown,02/03/10,2,10.5 PW_1236,Howard,Johnson,03/04/10,3,11 PW_1237,Francis,Themule,04/05/11,4,10.75 PW_1238,Mathew,Lewis,05/06/11,1,12.75 PW_1239,Mark,Bixton,05/13/11,2,13 PW_1242,Sarah,Glover,05/14/11,1,13.75 PW_1245,John,Doe,05/15/11,4,10.5 PW_1245,Mary,Doe,05/15/11,4,10.5 TL_1248,Abel,English,05/16/11,3,16.5,0.01,100,89 TL_1251,Eustis,Clauser,05/17/11,2,16,0.02,100,9 SU_1254,Henry,Hollowman,05/18/11,1,40000,0.01 PW_1240,Luke,Sailor,01/22/12,3,14.5 PW_1243,Jane,Baker,01/23/12,2,14 PW_1243,Jane,Baker,01/23/12,2,14 TL_1246,David,Brief,01/24/12,1,14.75,0.01,100,57 PW_1246,David,Doson,01/24/12,1,14.75 TL_1249,Baker,Anderson,01/25/12,4,11.5,0.01,100,100 TL_1252,Frank,Donson,01/26/12,3,17.5,0.02,100,39 SU_1255,Issac,Asimov,01/27/12,2,43000,0.02 SU_1256,Issac,Shoreman,01/28/12,3,39000,0.01 SU_1257,Issac,Roberts,01/29/12,4,35500,0.01 PW_1241,John,Candy,11/23/13,4,9.5 PW_1244,Kate,Smith,11/24/13,3,15.5 PW_1244,Kate,Handle,11/24/13,3,15.5 TL_1247,Samual,Dempky,11/25/13,2,15,0.01,100,10 TL_1250,Charley,Boman,11/26/13,1,15.75,0.01,100,50 TL_1253,George,Fritzmen,11/27/13,4,12.5,0.02,100,27

Here is the code:

private String makeEmployeeList()
{
    String list = "";

    for(int i=0; i < employees.length; i++)
    {
        list += "\n"+employees[i].toString();
        if(employees[i]substring(0,2).equals("SU"))
        {
            list += "\n"+employees[i].toString();
        }
    }
    return list;
}

**Here is how the employees array is created:

private Employee[] employees;

**Here is how everything is loaded into it.

public void loadEmployeesFromFile(String fileName)
            {
               File inFile = new File(fileName);
               if(inFile.exists())  //  MAKE SURE FILE EXISTS
               {    
                   try
                   {
                       BufferedReader inReader = new BufferedReader(new FileReader(inFile));
                      inReader.mark(32000);
                       String inLine = inReader.readLine();

                       //************************************
                       //  Counting rows to set array size
                       //************************************

                       int rowCount = 0;
                       while (inLine != null  && !inLine.equals(""))
                       {
                            rowCount++;
                           inLine = inReader.readLine();
                       }
                       inReader.reset();

                       //*******************
                       // re-reading data 
                       //*******************
                       this.employees = new Employee[rowCount];

                       for(int rowIndex = 0;rowIndex < rowCount; rowIndex++)
                       {
                            inLine = inReader.readLine();
                            Scanner employeeScanner = new Scanner(inLine).useDelimiter(",");
                            String workerType = employeeScanner.next();
                            String firstName = employeeScanner.next();
                            String lastName = employeeScanner.next();
                            String hireDate = employeeScanner.next();
                            int shift = employeeScanner.nextInt();

                            if(workerType.substring(0,2).equals("PW"))
                            {
                                double pay = employeeScanner.nextDouble();  
                                employees[rowIndex]= new ProductionWorker(workerType, firstName, lastName, hireDate, shift, pay);      
                            } 
                            else if(workerType.substring(0,2).equals("TL"))
                            {
                                double pay = employeeScanner.nextDouble();
                                double bonusRate = employeeScanner.nextDouble();
                                int reqHours = employeeScanner.nextInt();
                                int recHours = employeeScanner.nextInt();
                                employees[rowIndex]= new TeamLeader(workerType, firstName, lastName, hireDate, shift, pay, bonusRate, reqHours, recHours);      
                            } 
                            else if(workerType.substring(0,2).equals("SU"))
                            {
                                double salary = employeeScanner.nextDouble();
                                double bonusRate = employeeScanner.nextDouble();
                                employees[rowIndex]= new ShiftSupervisor(workerType, firstName, lastName, hireDate, shift, salary, bonusRate ); 
                            } 
                       }
                       return;
                   }catch(IOException ioe)
                   {
                       System.err.print("\nTrouble reading employee file: "+fileName);
                   }
               }
               JOptionPane.showMessageDialog(null, "\nFile Name does not exist!\n Process terminating!");
               System.exit(0);
            }

Answer 1

As you are using JOptionPane you can use html inside to give it format. Make an Employee class and make it's natural order by type, or you can use a Comparator if you don't want to use Comparable

I made a complete example for you.

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.swing.JOptionPane;

public class Employee implements Comparable<Employee> {
    private String type;
    private String name;

    public Employee(String type, String name) {
        super();
        this.type = type;
        this.name = name;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((type == null) ? 0 : type.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Employee other = (Employee) obj;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (type == null) {
            if (other.type != null)
                return false;
        } else if (!type.equals(other.type))
            return false;
        return true;
    }

    public int compareTo(Employee o) {
        if (this.type.equals(o.type)) {
            return name.compareTo(o.name);
        }
        return type.compareTo(o.type);
    }

    public static void main(String[] args) {
        List<Employee> employees = new ArrayList<Employee>();
        employees.add(new Employee("CA","John"));
        employees.add(new Employee("CA", "Suzy"));
        employees.add(new Employee("TA","Malcom"));
        employees.add(new Employee("AA","Rose"));

        // Sort the list by type as its natural order or use proper Comparator
        Collections.sort(employees);

        StringBuilder sb = new StringBuilder();
        sb.append("<html><table><tr><td>Type</td><td>Name</td></tr>");
        for (Employee e : employees) {
            sb.append("<tr>");
            sb.append("<td> ").append(e.getType()).append("</td>");
            sb.append("<td> ").append(e.getName()).append("</td>");
            sb.append("</tr>");
        }
        sb.append("</table></html>");
        JOptionPane.showMessageDialog(null, sb);
  }
}

Output:

Answer 2

private String makeEmployeeList(){ 
StringBuilder sbSU = null;

for(int i=0; i < employees.length; i++)
{
    sbSU = new StringBuilder();
    if(employees[i].substring(0,2).equals("SU"))
    {
        sbSU.append(employees[i].toString());
    }
}
return sbSU.toString();
}

First of all, you missed a dot after emplyees[i] subsrting As string is an immutable object, I suggest you use StringBuilder and its append method instead of +=. and use its toString() method to convert StringBuilder to a String. You also need to override your Employees's toString method.

to sort the employees in an array, you need to implements Comparable or Comparator interface so that the Array knows which criteria to use when sorting your employees, in your case it is to compare the employee's type