Cell validation in JTable

Question

I have a JTable that needs cell validation for the cells where the user can input text. When a user enters invalid text the border of the cell turns red.

I've managed to get this working associating a two dimension array to flag if each cell has errors or not.

The problem is that the user must be able to reorder the table (by column). I have to store the error flag in the table model, not separatly. Anyone has ideas how to do this?

Lithometeor

A user can only edit one cell at a time. Don't let them update the model until the data is valid. I don't see any need for a two dimensional array to keep track of error since all the data in the model should always be valid. – Emboss

You could also orientate the "error" state to by indexed by the model. This way you can convert the view index back to the model index as required. By I like camickr's suggest – Gleesome

Answer 1

Also consider a custom TableCellEditor, seen here and below. Adding an InputVerifier, as shown here, is a good alternative.

As the user must be able to reorder the table by column:

JTable provides methods that convert from model coordinates to view coordinates — convertColumnIndexToView and convertRowIndexToView — and that convert from view coordinates to model coordinates — convertColumnIndexToModel and convertRowIndexToModel.

Terramycin

Answer 2

I have tried one approach. We can use a TableCellRenderer and check the data in the cell and if the data is having error then just show it in RED. Here I have a StudentTableModel which will get the data to the table.

The table shows the cell RED if the cell contains special character like '@', '#', '$'. You can still reorder the table but still the rendering will take care of it. AFAIK flags are not required for achieving this.

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;

import com.amarnath.DragDrop.StudentTableModel;

public class TableErrorCheck {

    private JFrame frame;
    private JTable table;


    private void createUI() {

        frame = new JFrame();
        table = new JTable();
        table.setModel(new StudentTableModel());
        table.getColumnModel().getColumn(1).setCellRenderer(new ErrorCellRenderer());

        frame.setLayout(new BorderLayout());
        frame.add(new JScrollPane(table), BorderLayout.CENTER);
        frame.setTitle("Table Error Check.");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                new TableErrorCheck().createUI();
            }
        };

        EventQueue.invokeLater(r);
    }

}

class ErrorCellRenderer extends DefaultTableCellRenderer {

    private static final long serialVersionUID = 1L;

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value,
            boolean isSelected, boolean hasFocus, int row, int column) {
        Component component = super.getTableCellRendererComponent(table, value, isSelected, hasFocus,
                row, column);

        if(value.toString().contains("@") || value.toString().contains("$") || value.toString().contains("#")) {
            component.setBackground(Color.RED);
        } else {
            component.setBackground(Color.WHITE);
        }

        return component;
    }
}


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

import javax.swing.table.AbstractTableModel;

public class StudentTableModel extends AbstractTableModel {

    private static final long serialVersionUID = 1L;

    private List<StudentDO> data;

    private List<String> columnNames;

    public StudentTableModel() {
        data = getTableData();
        columnNames = getTableColumnNames();
    }

    public List<StudentDO> getData() {
        return data;
    }

    public void setData(List<StudentDO> data) {
        this.data = data;
    }

    @Override
    public Class<?> getColumnClass(int columnIndex) {
        switch (columnIndex) {
        case 0:
            return Boolean.class;
        case 1:
            return String.class;
        case 2:
            return String.class;
        default:
            return String.class;
        }
    }

    @Override
    public String getColumnName(int column) {
        return columnNames.get(column);
    }

    @Override
    public int getColumnCount() {
        return columnNames.size();
    }

    @Override
    public int getRowCount() {
        if(data == null) {
            return 0;
        }
        return data.size();
    }

    @Override
    public boolean isCellEditable(int rowIndex, int columnIndex) {
        if(columnIndex == 0 || columnIndex == 1) {
            return true;
        } else {
            return false;
        }
    }

    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        switch (columnIndex) {
        case 0:
            return data.get(rowIndex).isSelect();
        case 1:
            return data.get(rowIndex).getName();
        case 2:
            return data.get(rowIndex).getAge();
        default:
            return null;
        }
    }

    @Override
    public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
        switch (columnIndex) {
        case 0:
            data.get(rowIndex).setSelect((Boolean) aValue);
            break;
        case 1:
            data.get(rowIndex).setName(aValue == null ? null : aValue.toString());
            break;
        case 2:
            data.get(rowIndex).setAge(aValue == null ? new Integer(0) : Integer.parseInt(aValue.toString()));
            break;
        default:
            break;
        }
    }

    /**
     * Add a row.
     * @param index
     * @param studentDO
     */
    public void addRow(int index, StudentDO studentDO) {
        data.add(index, studentDO);
        fireTableDataChanged();
    }

    private List<StudentDO> getTableData() {
        List<StudentDO> list = new ArrayList<StudentDO>();

        for(int i = 0; i< 5; i++) {
            StudentDO student = new StudentDO();
            student.setSelect(false);
            student.setName("Stu " + i);
            student.setAge(10 + i);
            student.setIdentifier("ToapTable");

            list.add(student);
        }

        return list;
    }

    private List<String> getTableColumnNames() {
        List<String> columnNames = new ArrayList<String>();
        columnNames.add("Select");
        columnNames.add("Name");
        columnNames.add("Age");

        return columnNames;
    }
}

public class StudentDO {

    private boolean select;
    private String name;
    private int age;
      // Removed Getters and Setters .
}

P.S: Please let me know whether this is the good approach or not.

Waybill

@Che. Thanks. In fact, this is my approach. but there are 2 issues: 1)some cell validation rules depend on 2 cells 2)how can get iterate through the cell renderers and check the colour of the background? That's why i created a 2 dimensional array to check the errors... but that prevents row sorting (my question) – Lithometeor

@AlexandreGoncalves If you need to do sorting then you need to save the row numbers. – Waybill

@Che, i wanted to avoid saving the row numbers, to avoid messing things up... If i could access the renderer, i would know if it has background red (like your example) and then get the error status. but afaik that is not possible! – Lithometeor

@AlexandreGoncalves Okay let me suggest something. What if you don't allow to sort on table columns unless they clear the errors in the cells. (Just think abt it .. :-)) – Waybill