JTextPane StyledDocument insertString multi Icon problem (BUG?)

Question

Hi,
Now I am trying to insert some icons to the StyledDocument of JTextPane.
I found a problem that if I want to insert the same Icon (actually the same style which contains this icon) into the StyledDocument for more than one time, only the first insert operation works.
But if I insert a whitespace (or other non-zero length text) between the twe icon, it can works. I don't know it's my mis-using of this StyledDocument or it's a bug of JTextPane and StyledDocument?
Thanks!
My sample code below: To Run this code, you need to add a "icon" named "t1.jpg" in your project directory ^_^
import java.awt.BorderLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JTextPane;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;
import javax.swing.text.StyledDocument;
public class JTextPaneInsertIcons
     public static void main(String[] args) throws Exception
          JTextPane pane = new JTextPane();
          ImageIcon icon = new ImageIcon("t1.jpg");
          StyledDocument styledDocument = pane.getStyledDocument();
          Style iconStyle = styledDocument.addStyle("icon", null);
          StyleConstants.setIcon(iconStyle, icon);
          styledDocument.insertString(styledDocument.getLength(), " ", iconStyle);
          styledDocument.insertString(styledDocument.getLength(), " ", iconStyle);
          styledDocument.insertString(styledDocument.getLength(), "\n", StyleContext.getDefaultStyleContext().getStyle(StyleContext.DEFAULT_STYLE));
          styledDocument.insertString(styledDocument.getLength(), " ", iconStyle);
          styledDocument.insertString(styledDocument.getLength(), " ", StyleContext.getDefaultStyleContext().getStyle(StyleContext.DEFAULT_STYLE));
          styledDocument.insertString(styledDocument.getLength(), " ", iconStyle);
          JFrame frame = new JFrame();
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.getContentPane().add(pane, BorderLayout.CENTER);
          frame.setSize(360, 180);
          frame.setVisible(true);
}

Answer 1

OK, OK, I got it.
Thank you so much!
It seems I need to solve this problem ugly like this:
import java.awt.BorderLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JTextPane;
import javax.swing.text.AttributeSet;
import javax.swing.text.Element;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;
import javax.swing.text.StyledDocument;
public class JTextPaneInsertIcons
     static StyledDocument styledDocument;
     public static void main(String[] args) throws Exception
          JTextPane pane = new JTextPane();
          ImageIcon icon = new ImageIcon("1.jpg");
          styledDocument = pane.getStyledDocument();
          Style iconStyle = styledDocument.addStyle("icon", null);
          StyleConstants.setIcon(iconStyle, icon);
          insertOne(iconStyle);
          insertOne(iconStyle);
          JFrame frame = new JFrame();
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.getContentPane().add(pane, BorderLayout.CENTER);
          frame.setSize(600, 400);
          frame.setVisible(true);
     private static void insertOne(Style style) throws Exception
          if (style.getAttribute(StyleConstants.IconAttribute) != null)
               if (styledDocument.getLength() > 0)
                    Element e = styledDocument.getCharacterElement(styledDocument.getLength() - 1);
                    AttributeSet attributeSet = e.getAttributes();
                    if (style.getAttribute(StyleConstants.IconAttribute) == attributeSet
                              .getAttribute(StyleConstants.IconAttribute))
                         styledDocument.insertString(styledDocument.getLength(), " ", StyleContext
                                   .getDefaultStyleContext().getStyle(StyleContext.DEFAULT_STYLE));
          styledDocument.insertString(styledDocument.getLength(), " ", style);
}