JTable

A JTable must be attached to a TableModel.
A TableModel can be defined by:

implementing the TableModel interface
creating a class derived from AbstractTableModel
the methods

public int getRowCount();
public int getColumnCount();
public Object getValueAt(int row, int column)

must be defined

using DefaultTableModel

simple example

import javax.swing.table.AbstractTableModel;

public class TaskListModel extends AbstractTableModel {

public final static int TITLE = 0;
public final static int PRIORITY = 1;

private TaskList list;

    public TaskListModel (TaskList l) {
        list = l;
    }

    public int getRowCount() {
        return list.getSize();
    }

    public int getColumnCount() {
        return 2;
    }

public Object getValueAt(int row,
int column) {

Task task = list.getTask(row);

        switch (column) {
            case TITLE:
                return(task.getTitle());
            case PRIORITY:
                return(new Integer(task.getPriority()));
        }

return null;
}
}

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;

public class TaskManagerUI extends JFrame {

    public static void main(String[] args) {
        TaskManagerUI ui = new TaskManagerUI();
        ui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        ui.setSize(400,300);
        ui.setVisible(true);
    }

    public TaskManagerUI() {
        TaskList taskList = new TaskList("main");
        Container pane = getContentPane();
        pane.setLayout(new BorderLayout());
        TaskListModel taskListModel = new TaskListModel(taskList);
        JTable taskTable = new JTable(taskListModel);
        JScrollPane scrollPane = new JScrollPane(taskTable);
        pane.add(scrollPane, BorderLayout.CENTER);
    }
}

example of a complete table model

public class ResultRecorder implements javax.swing.table.TableModel {

    private java.util.Vector a_data;
    private javax.swing.event.EventListenerList a_listenerList;

    private static final int TEST_NAME = 0;
    private static final int TEST_DESCRIPTION = 1;
    private static final int RESULT_STATUS = 2;
    private static final int RESULT_DESCRIPTION = 3;

    private class ResultRecord {
        private String      a_testName;
        private String      a_testDescription;
        private CheckStatus a_resultStatus;
        private String      a_resultDescription;
        public ResultRecord(String testName,
                            String testDescription,
                            int    resultStatus,
                            String resultDescription) {
            a_testName = testName;
            a_testDescription = testDescription;
            a_resultStatus = new CheckStatus(resultStatus);
            a_resultDescription = resultDescription;
        }
        public String getTestName() { return a_testName; }
        public String getTestDescription() { return a_testDescription; }
        public CheckStatus getResultStatus() { return a_resultStatus; }
        public String getResultDescription() { return a_resultDescription; }
    }

    public ResultRecorder() {
        a_data = new java.util.Vector();
        a_listenerList = new javax.swing.event.EventListenerList();
    }

    void record(String testName,
                String testDescription,
                int    resultStatus,
                String resultDescription) {
       a_data.add( new ResultRecord(testName, testDescription, resultStatus, resultDescription) );
       javax.swing.event.TableModelEvent e;
       int n = a_data.size();
       e = new javax.swing.event.TableModelEvent(this,
                                                 n, n,
                                                 javax.swing.event.TableModelEvent.ALL_COLUMNS,
                                                 javax.swing.event.TableModelEvent.INSERT);
       java.util.EventListener[] list = a_listenerList.getListeners(javax.swing.event.TableModelListener.class);
       for (int i = list.length-1; i>=0; i--) {
             ((javax.swing.event.TableModelListener)list[i]).tableChanged(e);
       }
    }

    public Class getColumnClass(int columnIndex) {
        switch (columnIndex) {
            case TEST_NAME:
        return String.class;
            case TEST_DESCRIPTION:
        return String.class;
            case RESULT_STATUS:
        return CheckStatus.class;
            case RESULT_DESCRIPTION:
        return String.class;
        }
        return null;
    }

    public int getColumnCount() {
        return 4;
    }

    public int getRowCount() {
        return a_data.size();
    }

    public String getColumnName(int columnIndex) {
        switch (columnIndex) {
            case TEST_NAME:
                return "test";
            case TEST_DESCRIPTION:
                return "description";
            case RESULT_STATUS:
                return "status";
            case RESULT_DESCRIPTION:
                return "result";
        }
        return null;
    }

    public Object getValueAt(int rowIndex, int columnIndex) {
        ResultRecord r = (ResultRecord)a_data.get(rowIndex);
        switch (columnIndex) {
            case TEST_NAME:
                return r.getTestName();
            case TEST_DESCRIPTION:
                return r.getTestDescription();
            case RESULT_STATUS:
                return r.getResultStatus();
            case RESULT_DESCRIPTION:
                return r.getResultDescription();
        }
        return null;

    }

    public boolean isCellEditable(int rowIndex, int columnIndex) {
        return false;
    }

    public void addTableModelListener(javax.swing.event.TableModelListener l) {
        a_listenerList.add(javax.swing.event.TableModelListener.class, l);
    }

    public void removeTableModelListener(javax.swing.event.TableModelListener l) {
        a_listenerList.remove(javax.swing.event.TableModelListener.class, l);
    }

    public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
    }
}

use public String getColumnName(int column) of the TableModel to define the titles of the columns (otherwise, the default is 'A', 'B'...)
use public Class getColumnClass(int column) of the TableModel to define the classes of the elements in each columns (used to set up the renderers and editors)
use public boolean isCellEditable(int row, int column) of the TableModel to allow edition of cells (default is that cells are not editable)

definition of a renderer to change the background color

class
ResultTableCellRenderer extends
javax.swing.table.DefaultTableCellRenderer {

    

    public java.awt.Component
getTableCellRendererComponent( javax.swing.JTable table,

                                                            
Object value,

                                                            
boolean isSelected,

                                                            
boolean hasFocus,

                                                            
int row,

                                                            
int column ) {

        java.awt.Component renderer
= super.getTableCellRendererComponent(table, value, isSelected,
hasFocus, row, column);

        

        if
(table.getColumnModel().getColumn(column).getModelIndex() == 2) {

           
String str = (String)value;

            if (
str.equals("success") ) {

               
renderer.setBackground(java.awt.Color.green);

            }
else if ( str.equals("warning") ) {

               
renderer.setBackground(java.awt.Color.orange);

            }
else {

               
renderer.setBackground(java.awt.Color.red);

            }

        }

        else {

           
renderer.setBackground(java.awt.Color.white);

        }

        

        return this;

    }

}

taskTable.setDefaultRenderer(String.class,new
ResultTableCellRenderer());

or better, create a class and attach a special cell rendered to it

public class CheckStatus {

    public static final int SUCCESS = 1;
    public static final int WARNING = 2;
    public static final int FAILURE = 3;

    int a_status;

    public CheckStatus(int status) {
        a_status = status;
    }

    public String toString() {
        switch (a_status) {
            case SUCCESS:
                return "Success";
            case WARNING:
                return "Warning";
            case FAILURE:
                return "Failure";
        }
        return null;
    }

    public java.awt.Color getColor() {
        switch (a_status) {
            case SUCCESS:
                return java.awt.Color.green;
            case WARNING:
                return java.awt.Color.orange;
            case FAILURE:
                return java.awt.Color.red;
        }
        return null;
    }
}

class CheckStatusCellRenderer extends javax.swing.table.DefaultTableCellRenderer {

    public java.awt.Component getTableCellRendererComponent( javax.swing.JTable table,
                                                             Object value,
                                                             boolean isSelected,
                                                             boolean hasFocus,
                                                             int row,
                                                             int column ) {
        java.awt.Component renderer = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        CheckStatus status = (CheckStatus)value;
        renderer.setBackground(status.getColor());
        return this;
    }
}

taskTable.setDefaultRenderer(CheckStatus.class,new CheckStatusCellRenderer());

definition of a renderer for the dates

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.table.DefaultTableCellRenderer;

public class DateTimeCellRenderer extends DefaultTableCellRenderer {

final static DateFormat format = new SimpleDateFormat("EEEE d MMMM yyyy HH:mm:ss");

    public DateTimeCellRenderer() {
        super();
    }

    public void setValue(Object value) {
        Date date = (Date)value;
        super.setValue(format.format(date));
    }
}

table.setDefaultRenderer(java.util.Date.class, new DateTimeCellRenderer);

definition of an editor for the dates

import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.DefaultCellEditor;
import javax.swing.JTextField;

public class DateTimeCellEditor extends DefaultCellEditor {

static final DateFormat format = new SimpleDateFormat("dd/MM/yy HH:mm:ss");

    public DateTimeCellEditor(JTextField textField) {
        super(textField);
        this.delegate = new EditorDelegate() {
            public void setValue(Object value) {
                Date date = (Date)value;
                ((JTextField)editorComponent).setText(format.format(date));
            }
            public Object getCellEditorValue() {
                String text = ((JTextField)editorComponent).getText();
                Date date = format.parse(text, new ParsePosition(0));
                return date;
            }
        };
    }
}

table.setDefaultEditor(java.util.Date.class, new DateTimeCellEditor(new JtextField()));

set the columns widths
TableColumn column = null;
for (int i = 0; i < 5; i++) {
    column = table.getColumnModel().getColumn(i);
    if (i == 2) {
        column.setPreferredWidth(100); //sport column is bigger
    } else {
        column.setPreferredWidth(50);
    }
}

Last update: March 13^th, 2004 - Laurent