use std, forms, functional

text = map(range(1, 16), def(x) = "line " + x).joinToString("\n")
label = newLabel()
textArea = newTextArea(text)
textArea.addCaretListener(def(event) = updateInfo())
textArea.addDocumentListener(def(type, event) = updateInfo())
updateInfo()

def updateInfo() {
  text = "Text length: " + textArea.getText().length
  text += ", lines: " + textArea.getLineCount()
  selectedText = default(textArea.getSelectedText(), "")
  if (!selectedText.isEmpty()) {
    text += ", selected: " + selectedText.length
  }
  label.setText(text)
}

window = newWindow("JTextArea example")
window.add(newScrollPane(textArea), BorderLayout.CENTER)
window.add(label, BorderLayout.SOUTH)
window.setSize(300, 200)
window.setLocationByPlatform()
window.setVisible()