Output text view information from JTextField in Java

/*www.java  2 s  . c o  m*/
import java.io.PrintStream;

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;
import javax.swing.text.View;

public class Main {
  public static void main(String[] args) {
    JFrame f = new JFrame("Text Field View");
    JTextField tf = new JTextField(32);
    tf.setText("That's one small step for man...");
    f.getContentPane().add(tf);
    f.pack();
    f.setVisible(true);

    ViewDisplayer.displayViews(tf, System.out);
  }
}

class ViewDisplayer {
  public static void displayViews(JTextComponent comp, PrintStream out) {
    View rootView = comp.getUI().getRootView(comp);
    displayView(rootView, 0, comp.getDocument(), out);
  }

  public static void displayView(View view, int indent, Document doc,
      PrintStream out) {
    String name = view.getClass().getName();
    for (int i = 0; i < indent; i++) {
      out.print("\t");
    }

    int start = view.getStartOffset();
    int end = view.getEndOffset();
    out.println(name + "; offsets [" + start + ", " + end + "]");
    int viewCount = view.getViewCount();
    if (viewCount == 0) {
      int length = Math.min(32, end - start);
      try {
        String txt = doc.getText(start, length);
        for (int i = 0; i < indent + 1; i++) {
          out.print("\t");
        }
        out.println("[" + txt + "]");
      } catch (BadLocationException e) {
      }
    } else {
      for (int i = 0; i < viewCount; i++) {
        displayView(view.getView(i), indent + 1, doc, out);
      }
    }
  }
}