JInternalFrame not displaying JTable

[Dorothy Turner]

I am trying to display a JTable that takes a LogRecord and shows the time at which the record was raised as well as the actual message. The message is supposed to be color-coded by the LogRecord's Level, so for instance, Level.Info is displayed as black, a warning is yellow, and severe is red.

The JTable is situated in a JScrollPane, which is part of a JInternalFrame, which is then housed in a JDesktopPane.

When I run my test program, the window for the JTable does pop up, but it is blank. If I manually drag and resize the window, the JTable appears, but the color coding is incorrect. The text is all colored yellow, when it should be red and yellow. I noticed that the final text color is dependent on the last LogRecord the table receives. So for example, the code currently passes a Warning as the last message, so the table text is all yellow. I tried passing Severe as the final message, and similarly the text was all red. I see why that happens. In TestFrame.java, there is a global Level variable that stores the level of the current LogRecord and colors the text accordingly. What seems to be happening is that all the messages are passed to the JTable before I manually resize the window, and once it becomes visible, that is when the JTable is actually constructed. As a result, the global Level variable will always represent the last message passed.

I hope that explanation all made sense so far. I've posted the two pieces of code below. TestFrame is the code for the actual JInternalFrame, and TestFrameTest is where I place the internal frame in a desktop pane and pass LogRecords.


Here's TestFrame.java:

import java.awt.Color;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.LogRecord;
 
import javax.swing.JInternalFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
 

 
/**
 * Displays messages logged in the system.
 */
public class TestFrame extends JInternalFrame   
{
private myTableModel model;
private JTable display;
private JScrollPane scrollPane;
private Level currentLevel;

/**
 * Constructor.
 */
public TestFrame(){
super("Message Viewer", true, true, true, true);
model = new myTableModel();
display = new JTable(model);

ColoredCellRenderer ccr = new ColoredCellRenderer();
display.setDefaultRenderer(Object.class, ccr);

model.addColumn("Time");
model.addColumn("Message");
scrollPane = new JScrollPane(display);


//this.add(scrollPane);
this.getContentPane().add(scrollPane);
this.setSize(800, 200);
this.setTitle("Message Viewer");

this.setVisible(true);
this.setResizable(true);
try{
 this.setSelected(true);
}
catch(java.beans.PropertyVetoException e){
System.out.println("exception");
}
pack();
}

  /**
   * Recieve log message from Message Handler.
   * @param message The log message.
   */
  public void messageRaised(LogRecord message){
  this.repaint();
 //extract relevant information from LogRecord
   currentLevel = message.getLevel();
   System.out.println(currentLevel);
   String text = message.getMessage();
   Date date = new Date(message.getMillis());
   
   model.addRow(new Object[]{date, text});
   this.repaint();
  }
  
  /**
   * Creates a JTable whose cells are not editable
   */
  private class myTableModel extends DefaultTableModel{

 
public boolean isCellEditable(int row, int column){
  return false;
  }
  }
  
  /**
   * Allows the display of colored text 
   */
  private class ColoredCellRenderer extends DefaultTableCellRenderer{
 
public void setValue(Object value){
  if(value instanceof String){
  //we only need colored text if we are displaying a Level value, not a Date
  if (currentLevel == Level.SEVERE){
  setForeground(Color.RED);
  }
  else if (currentLevel == Level.WARNING){
  setForeground(Color.YELLOW);
  }
  else{
  setForeground(Color.BLACK);
  }
  }
  else{
  setForeground(Color.BLACK);
  }
  super.setValue(value);
  
  }
  }
 

}
 

Here's TestFrameTest.java:

import java.util.logging.Level;
import java.util.logging.LogRecord;
 
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
 

public class TestFrameTest
{
  public static void main(String[] args)
  {
TestFrame test = new TestFrame();


JFrame frame = new JFrame("JTable Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

// create the desktop pane that  
JDesktopPane pane = new JDesktopPane();


test.setVisible(true);
   
// add messager to desktop pane
pane.add(test);

try{
 test.setSelected(true);
}
catch(java.beans.PropertyVetoException e){
System.out.println("exception");
}

// add desktop pane to frame
frame.setContentPane(pane);

frame.setVisible(true);
frame.setSize(900, 400);


for(int i = 0; i < 3; ++i)
{
test.messageRaised(new LogRecord(Level.SEVERE, "severe"));
  test.messageRaised(new LogRecord(Level.WARNING, "warning"));
}
  }
}

[Michael Dunn]

> When I run my test program, the window for the JTable does pop up, but it is blank.

frame.setVisible(true) is in the wrong spot

> The text is all colored yellow,

you would need to associate a currentLevel with each value, otherwise when
the last row is added, all is rendered again, based on the global 'currentLevel'

here's an example, using the renderer's getTableCellRenderComponent where
the color is set based on each value
I've changed a lot around - I don't have(or don't seem to have) some of the classes,
but it should be simple enough to put back.

    
import java.awt.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
 
class TestFrame extends JInternalFrame
{
  private myTableModel model;
  private JTable display;
  private JScrollPane scrollPane;
  private int currentLevel;
  public TestFrame()
  {
    super("Message Viewer", true, true, true, true);
    model = new myTableModel();
    display = new JTable(model);
    ColoredCellRenderer ccr = new ColoredCellRenderer();
    display.setDefaultRenderer(Object.class, ccr);
    model.addColumn("Time");
    model.addColumn("Message");
    scrollPane = new JScrollPane(display);
    this.getContentPane().add(scrollPane);
    this.setSize(800, 200);
    this.setTitle("Message Viewer");
    this.setVisible(true);
    this.setResizable(true);
    try{this.setSelected(true);}
    catch(java.beans.PropertyVetoException e){System.out.println("exception");}
    pack();
  }
  public void messageRaised(String message)
  {
     Date date = new Date();
     model.addRow(new Object[]{date, message});
  }
  private class myTableModel extends DefaultTableModel
  {
    public boolean isCellEditable(int row, int column){return false;}
  }
  private class ColoredCellRenderer extends DefaultTableCellRenderer//<---------changed this
  {
    public Component getTableCellRendererComponent(JTable table, Object value,boolean isSelected, boolean hasFocus,int row, int column)
    {
      Component comp = super.getTableCellRendererComponent(table, value,isSelected, hasFocus, row, column);
      if(value instanceof String)
      {
        if (value.equals("severe")) comp.setForeground(Color.RED);
        else if (value.equals("warning")) comp.setForeground(Color.YELLOW);
        else comp.setForeground(Color.BLACK);
      }
      else comp.setForeground(Color.BLACK);
      return comp;
    }
  }
}
class TestFrameTest
{
  public static void main(String[] args)
  {
    TestFrame test = new TestFrame();
    JFrame frame = new JFrame("JTable Test");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JDesktopPane pane = new JDesktopPane();
    test.setVisible(true);
    pane.add(test);
    try{test.setSelected(true);}
    catch(java.beans.PropertyVetoException e){System.out.println("exception");}
    frame.setContentPane(pane);
    //frame.setVisible(true);//<---------------moved, see below
    frame.setSize(900, 400);
    for(int i = 0; i < 3; ++i)
    {
      test.messageRaised("severe");
      test.messageRaised("normal");
      test.messageRaised("warning");
    }
    frame.setVisible(true);//<------------moved to here
  }
}

[Dorothy Turner]

That was perfect. Thank you for your help