Sort JTable Except for Last Row

Question

I have a JTable where the last row is the total row that aggregates all other rows. When the user clicks a column header on the table, rows are sorted by that c

Answer 1

Based on this example, the complete example example below illustrates the approach in the accepted answer. In particular,

• The implementation of getRowCount() in the TableModel returns the size() of the List, which is one less than the number of rows displayed in the table.

• The implementation of getValueAt() in the TableModel illustrates the call to sum() in the COLUMN_SALARY and some possible display choices for the remaining columns in the extra row at the bottom.

• The implementation of getViewRowCount() in the TableRowSorter enables the display of the extra row but precludes reasonable filtering.

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.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;
import javax.swing.table.TableRowSorter;

/**
 * @see https://stackoverflow.com/a/37913520/230513
 * @see https://stackoverflow.com/a/37892395/230513
 */
public class JTableColumnTotalExample {

    public static void main(String[] args) {
        EventQueue.invokeLater(JTableColumnTotalExample::display);
    }

    public static void display() {
        JFrame f = new JFrame("JTable Sorting Example");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        List 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());
        TableRowSorter sorter = new TableRowSorter(model) {
            @Override
            public int convertRowIndexToModel(int index) {
                int maxRow = super.getViewRowCount();
                if (index >= maxRow) {
                    return index;
                }
                return super.convertRowIndexToModel(index);
            }

            @Override
            public int convertRowIndexToView(int index) {
                int maxRow = super.getModelRowCount();
                if (index > maxRow) {
                    return index;
                }
                return super.convertRowIndexToView(index);
            }

            @Override
            public int getViewRowCount() {
                return super.getViewRowCount() + 1;
            }
        };
        table.setRowSorter(sorter);
        f.add(new JScrollPane(table), BorderLayout.CENTER);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private static List createListEmployees() {
        List 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 final String[] columnNames = {"No", "Name", "Job", "Salary"};
        private final List listEmployees;

        public EmployeeTableModel(List 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) {
            if (rowIndex == getRowCount()) {
                switch (columnIndex) {
                    case COLUMN_NUM:
                        return 999_999_999;
                    case COLUMN_NAME:
                        return "Total";
                    case COLUMN_JOB:
                        return "Salary";
                    case COLUMN_SALARY:
                        return sum();
                }
            }
            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();
                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 NumberFormat numberFormat = 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 = numberFormat.format(num);
                label.setText(text);
            }
            return c;
        }
    }
}