Get a component from a JTextPane through javax.swing.text.Element?

Question

I am using a `JTextPane` to display characters and symbols, where the latter are represented by custom painted `JComponents`. For example, the text pane might show something like this: The text pane is user editable and it is allowed for the user to add more symbols via a button at any position and as a replacement for selected text. I do this via the `JTextPane.insertComponent()` method. At some point in the application I need to know what is currently being displayed in the text pane, and by that I mean not only the entered text, but also the exact components contained within. I went through extensive troubles with `Positions` and `DocumentListeners` to manage the content of my text pane, but I kept causing more problems than I was solving. That is why I finally decided, that my troubles are probably due to a design fault on my part, so I decided to see, if I can't get to my components through the text pane. Searching through the documentation and the source code of `AbstractDocumen…

Accepted Answer

You can traverse the text pane's `StyledDocument` to find elements that represent components or icons, as shown below.

```
BranchElement(section) 0,7

BranchElement(paragraph) 0,7

LeafElement(content) 0,4

LeafElement(icon) 4,5

class javax.swing.plaf.IconUIResource
LeafElement(component) 5,6

class javax.swing.JLabel
LeafElement(content) 6,7
```

SSCCE:

```
/**
 * @see http://stackoverflow.com/a/15669307/230513
 * @see http://stackoverflow.com/questions/2883413
 */
public class DocumentParse {

private static final String ELEM = AbstractDocument.ElementNameAttribute;
    private static final String ICON = StyleConstants.IconElementName;
    private static final String COMP = StyleConstants.ComponentElementName;

public static void main(String args[]) throws Exception {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JTextPane jtp = new JTextPane();
        StyledDocument doc = (StyledDocument) jtp.getDocument();
        SimpleAttributeSet normal = new SimpleAttributeSet();
        StyleConstants.setFontFamily(normal, "Serif");
        StyleConstants.setFontSize(normal, 72);
        StyleConstants.setForeground(normal, Color.blue);
        doc.insertString(doc.getLength(), "Test", normal);
        jtp.setSelectionStart(doc.getLength());
        jtp.insertIcon(UIManager.getIcon("OptionPane.warningIcon"));
        jtp.setSelectionStart(doc.getLength());
        jtp.insertComponent(new JLabel("Label"));
        jtp.setSelectionStart(doc.getLength());

ElementIterator iterator = new ElementIterator(doc);
        Element element;
        while ((element = iterator.next()) != null) {
            System.out.println(element);
            AttributeSet as = element.getAttributes();
            if (as.containsAttribute(ELEM, ICON)) {
                System.out.println(StyleConstants.getIcon(as).getClass());
            }
            if (as.containsAttribute(ELEM, COMP)) {
                System.out.println(StyleConstants.getComponent(as).getClass());
            }
        }

f.add(jtp);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}
```

Get a component from a JTextPane through javax.swing.text.Element?

Solution

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