How do I select a paragraph element spanning multiple lines

Question

Hi,
I would like to retrieve the text from a JTextArea that surrounds the caret. What I mean by this is that I would like to select out the text around the caret that is a legitimate paragraph not the one associated with PlainDocument.
ie.
blah blah blah
text text <caret> text
text text text text
blah blah blah blah
In this scenario I would like to select out the two lines containing "text." I would like to do this without having to write my own code to parse the document. Your help is greatly appreciated.
Thanks,
John

Answer 1

You could do something like this, although somewhat tedious. Hope it will help!
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.text.*;
public class ParagraphSelectionTest
  public static void main(String[] args)
    JFrame frame = new JFrame("Paragraph selection");
    frame.setSize(500, 300);
    JTextArea tp = new JTextArea();
    frame.getContentPane().setLayout(new BorderLayout());
    frame.getContentPane().add(new JScrollPane(tp), BorderLayout.CENTER);
    frame.getContentPane().add(new JButton(new ParagraphSelectionAction(tp)), BorderLayout.SOUTH);
    frame.setVisible(true);
class ParagraphSelectionAction extends AbstractAction
  private JTextArea m_textArea;
  public ParagraphSelectionAction(JTextArea textArea)
    super("Select paragraph");
    m_textArea = textArea;
  public void actionPerformed(ActionEvent e)
    Element caretElement = ((PlainDocument)m_textArea.getDocument()).
        getParagraphElement(m_textArea.getCaretPosition());
    boolean bStartSet = false;
    boolean bFound = false;
    int nStart = 0;
    int nEnd = 0;
    for (Enumeration enum = ((AbstractDocument.BranchElement)caretElement.getParentElement()).children();
        enum.hasMoreElements(); )
      Element el = (AbstractDocument.LeafElement)enum.nextElement();
      if (!bStartSet)
        nStart = el.getStartOffset();
        bStartSet = true;
      if (el == caretElement)
        bFound = true;
      if (el.getEndOffset() - el.getStartOffset() == 1)
        if (el == caretElement)
          nEnd = nStart;
        if (bFound)
          break;
        else
          bStartSet = false;
      nEnd = el.getEndOffset();
    m_textArea.setSelectionStart(nStart);
    m_textArea.setSelectionEnd(nEnd);
    m_textArea.getCaret().setSelectionVisible(true);
}