As shown here, here and here, you can calculate derived values in your implementation of getValueAt(). In the example below,
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.List;
import javax.swing.DefaultRowSorter;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableModel;
/**
* @see https://stackoverflow.com/posts/38192710/edit
* @see https://stackoverflow.com/a/37913520/230513
* @see https://stackoverflow.com/a/37892395/230513
*/
public class JTablePercentTotalExample {
public static void main(String[] args) {
EventQueue.invokeLater(JTablePercentTotalExample::display);
}
public static void display() {
JFrame f = new JFrame("JTable Sorting Example");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
List<Employee> listEmployees = createListEmployees();
TableModel model = new EmployeeTableModel(listEmployees);
JTable table = new JTable(model) {
@Override
public Dimension getPreferredScrollableViewportSize() {
return new Dimension(500, getRowCount() * getRowHeight());
}
};
table.getColumnModel().getColumn(3).setCellRenderer(new CurrencyFormatter());
table.getColumnModel().getColumn(4).setCellRenderer(new PercentFormatter());
table.setAutoCreateRowSorter(true);
DefaultRowSorter sorter = (DefaultRowSorter) table.getRowSorter();
sorter.setSortable(4, false);
f.add(new JScrollPane(table), BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private static List<Employee> createListEmployees() {
List<Employee> listEmployees = new ArrayList<>();
listEmployees.add(new Employee("Peter", "Manager", 40000));
listEmployees.add(new Employee("Paul", "Programmer", 25000));
listEmployees.add(new Employee("Mary", "Designer", 25000));
listEmployees.add(new Employee("Donald", "Leader", 30000));
listEmployees.add(new Employee("Tom", "Designer", 28000));
listEmployees.add(new Employee("Samantha", "Analyst", 50000));
listEmployees.add(new Employee("Jerome", "Programmer", 32000));
listEmployees.add(new Employee("Jonathon", "Developer", 29000));
listEmployees.add(new Employee("Kevin", "Programmer", 23000));
listEmployees.add(new Employee("Anthony", "Programmer", 23000));
listEmployees.add(new Employee("John", "Designer", 33000));
listEmployees.add(new Employee("David", "Developer", 28000));
listEmployees.add(new Employee("Harry", "Designer", 31000));
listEmployees.add(new Employee("Charles", "Programmer", 26000));
listEmployees.add(new Employee("Joseph", "Manager", 40000));
return listEmployees;
}
private static class EmployeeTableModel extends AbstractTableModel {
private static final int COLUMN_NUM = 0;
private static final int COLUMN_NAME = 1;
private static final int COLUMN_JOB = 2;
private static final int COLUMN_SALARY = 3;
private static final int COLUMN_PERCENT = 4;
private final String[] columnNames = {"No", "Name", "Job", "Salary", "Percent"};
private final List<Employee> listEmployees;
public EmployeeTableModel(List<Employee> listEmployees) {
this.listEmployees = listEmployees;
int indexCount = 1;
for (Employee employee : listEmployees) {
employee.setIndex(indexCount++);
}
}
@Override
public int getColumnCount() {
return columnNames.length;
}
@Override
public int getRowCount() {
return listEmployees.size();
}
@Override
public String getColumnName(int columnIndex) {
return columnNames[columnIndex];
}
@Override
public Class<?> getColumnClass(int columnIndex) {
return getValueAt(0, columnIndex).getClass();
}
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
Employee employee = listEmployees.get(rowIndex);
switch (columnIndex) {
case COLUMN_NUM:
return employee.getIndex();
case COLUMN_NAME:
return employee.getName();
case COLUMN_JOB:
return employee.getJob();
case COLUMN_SALARY:
return employee.getSalary();
case COLUMN_PERCENT:
int salary = (int) getValueAt(rowIndex, COLUMN_SALARY);
return Double.valueOf(salary / (double) sum());
default:
throw new IllegalArgumentException("Invalid column index");
}
}
private int sum() {
int sum = 0;
for (int r = 0; r < getRowCount(); r++) {
sum += (int) getValueAt(r, COLUMN_SALARY);
}
return sum;
}
}
private static class Employee {
private int index;
private String name;
private String job;
private int salary;
public Employee(String name, String job, int salary) {
this.name = name;
this.job = job;
this.salary = salary;
}
public int getIndex() {
return index;
}
public void setIndex(int index) {
this.index = index;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getJob() {
return job;
}
public void setJob(String job) {
this.job = job;
}
public int getSalary() {
return salary;
}
public void setSalary(int age) {
this.salary = age;
}
}
private static class CurrencyFormatter extends DefaultTableCellRenderer {
private final NumberFormat nf = NumberFormat.getCurrencyInstance();
@Override
public Component getTableCellRendererComponent(JTable jTable, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
Component c = super.getTableCellRendererComponent(jTable, value,
isSelected, hasFocus, row, column);
if (c instanceof JLabel && value instanceof Number) {
JLabel label = (JLabel) c;
label.setHorizontalAlignment(JLabel.RIGHT);
Number num = (Number) value;
String text = nf.format(num);
label.setText(text);
}
return c;
}
}
private static class PercentFormatter extends DefaultTableCellRenderer {
private NumberFormat nf = NumberFormat.getPercentInstance();
@Override
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
Component c = super.getTableCellRendererComponent(table, value,
isSelected, hasFocus, row, column);
if (c instanceof JLabel && value instanceof Number) {
JLabel label = (JLabel) c;
label.setHorizontalAlignment(JLabel.RIGHT);
Number num = (Number) value;
String text = nf.format(num);
label.setText(text);
}
return c;
}
}
}
