How to set the style of inputted text to that which immediately follows the cursor position in a JTextPane

Question

I'm working on a database program where the GUI has multiple input areas, some of which are JTextPanes where the user can set Bold, Underline, and Italic styles on their text. When the user places their cursor immediately adjacent to an area that is already bold, for example, I want the next text that they type to likewise be bold. So far, the only thing that is happening is that text typed immediately after bolded text is bold, but I cannot seem to make it so that text typed in immediately before bolded text is likewise bold.

I'm not sure that all was any less than confusing, so here's an example: Presume the sentence, "Java is fun." is already in one of the JTextPanes.

If the user places the cursor to the left or right of "is", I want whatever they type next to likewise be bold. Like this, "Java fooisbar fun."

So far, I am only getting, "Java fooisbar fun."

What follows is the method I am using to add style-detecting functionality to the caret of a JTextPane and what I thought would work to do this.

I've also tried adding an additional new StyledEditorKit.BoldAction().actionPerformed(null) before or after the boldButton.setSelected(true) but that didn't have any effect. I also attempted tp.getStyledDocument().setCharacterAttributes(caretPosition -1, 1, asPrev, true), and while that did make the next text inputted bold, the results were unpredictable, with random line breaks and missing characters happening. Changing boldButton.setSelected(true) to boldButton.doClick() didn't have any effect, nor did using my ButtonAction class to set the text to bold.

        int lastCaretPosition;
        public void formatAndAddFunctions(Component c) {
            Font normalFont = new Font("Tahoma", Font.PLAIN, 11);
            c.setFont(normalFont);
            
            if (c instanceof JTextField) {
                ((JTextField) c).setAlignmentX(Component.LEFT_ALIGNMENT);
                ((JTextField) c).addFocusListener(new java.awt.event.FocusAdapter() {
                     @Override
                     public void focusGained(java.awt.event.FocusEvent evt) {
                         ((JTextField) c).selectAll();
                         activeComponent = c;
                     }
                });
                UndoTool.addUndoFunctionality((JTextField) c);
            }
            
            if (c instanceof JScrollPane) {
                ((JScrollPane) c).setAlignmentX(Component.LEFT_ALIGNMENT);
                JViewport vp = ((JScrollPane) c).getViewport();
                JTextPane tp = (JTextPane) vp.getView();
                tp.setContentType("text/html");
                tp.putClientProperty(JEditorPane.HONOR_DISPLAY_PROPERTIES, true);
                tp.addFocusListener(new java.awt.event.FocusAdapter() {
                     @Override
                     public void focusGained(java.awt.event.FocusEvent evt) {
                         activeComponent = tp;
                     }
                });
                UndoTool.addUndoFunctionality(tp);
                
                //look at the character attibutes before and after the caret to see if they are
                //formatted bold, underline, and/or italic
                lastCaretPosition = -1;
                tp.addCaretListener((CaretEvent ce) -> {
                    int caretPosition = tp.getCaretPosition();
                    if(caretPosition != lastCaretPosition) {
                        lastCaretPosition = caretPosition;
                        
                        Element charElementPrev = tp.getStyledDocument().getCharacterElement(caretPosition - 1);
                        AttributeSet asPrev = charElementPrev.getAttributes();
                        Element charElementAfter = tp.getStyledDocument().getCharacterElement(caretPosition);
                        AttributeSet asAfter = charElementAfter.getAttributes();

                        if ((StyleConstants.isBold(asPrev) || StyleConstants.isBold(asAfter)) && !boldButton.isSelected()) {
                            boldButton.setSelected(true);
                        } else if((!StyleConstants.isBold(asPrev) && !StyleConstants.isBold(asAfter)) && boldButton.isSelected()) {
                            boldButton.setSelected(false);
                        }

                        if ((StyleConstants.isUnderline(asPrev) || StyleConstants.isUnderline(asAfter)) && !ulButton.isSelected()) {
                            ulButton.setSelected(true);
                        } else if ((!StyleConstants.isUnderline(asPrev) && !StyleConstants.isUnderline(asAfter)) && ulButton.isSelected()) {
                            ulButton.setSelected(false);
                        }

                        if ((StyleConstants.isItalic(asPrev) || StyleConstants.isItalic(asAfter)) && !itButton.isSelected()) {
                            itButton.setSelected(true);
                        } else if ((!StyleConstants.isItalic(asPrev) && !StyleConstants.isItalic(asAfter)) && itButton.isSelected()) {
                            itButton.setSelected(false);
                        }
                    }
                });

                tp.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_B, java.awt.event.InputEvent.CTRL_DOWN_MASK), "boldKeystroke");
                tp.getActionMap().put("boldKeystroke", new ButtonAction("bold"));

                tp.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_U, java.awt.event.InputEvent.CTRL_DOWN_MASK), "underlineKeystroke");
                tp.getActionMap().put("underlineKeystroke", new ButtonAction("underline"));

                tp.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_I, java.awt.event.InputEvent.CTRL_DOWN_MASK), "italicKeystroke");
                tp.getActionMap().put("italicKeystroke", new ButtonAction("italic"));
            }
        }

And, for reference, the boldButton's code:

boldButton = new JToggleButton();
            
boldButton.setIcon(allIcons[39]);
boldButton.setRolloverIcon(allIcons[40]);
boldButton.setSelectedIcon(allIcons[41]);
boldButton.setToolTipText("Bold");
boldButton.setBorderPainted(false);
boldButton.setContentAreaFilled(false);
boldButton.setFocusable(false);
boldButton.setBorder(null);
boldButton.setMargin(noInset);
boldButton.addActionListener((java.awt.event.ActionEvent e) -> {
    new StyledEditorKit.BoldAction().actionPerformed(e);
    activeComponent.requestFocusInWindow();
});

The odd thing is that if I set the cursor right before bolded text, and then click on the Bold toggle button in the UI, the next text typed does come out bold. But I can't seem to get this to happen programmatically. Any ideas?