Temperature1.scala

object Temperature {
  def main(args: Array[String]): Unit = {
    val display = Display.getDefault
    val window = new Shell(display)
    window.setMinimumSize(400, 150)
    window.pack
    window.setLayout(new GridLayout());
    new Temperature(window, SWT.NONE)
    window.open
    while (!window.isDisposed) {
      if (!display.readAndDispatch) display.sleep
    }
  }

  class Temperature(parent: Composite, style: Int) extends Composite(parent, style) {
    def applyLayoutData(c: Control) = GridDataFactory.defaultsFor(c).applyTo(c)
    def parseDouble(s: String) = java.lang.Double.parseDouble(s)

    setLayout(new GridLayout(2, true))

    new Label(this, SWT.NULL).setText("Fahrenheit")
    new Label(this, SWT.NULL).setText("Celcius")

    val fahrenheit = new Text(this, SWT.BORDER)
    applyLayoutData(fahrenheit)

    val celcius = new Text(this, SWT.BORDER)
    applyLayoutData(celcius)

    val fahrenheitToCelcius = new Button(this, SWT.PUSH)
    fahrenheitToCelcius.setText("Fareinheight -> Celcius")
    fahrenheitToCelcius.addSelectionListener(new SelectionAdapter() {
      override def widgetSelected(e: SelectionEvent) = {
        val fDouble = parseDouble(fahrenheit.getText())
        val cDouble = (5.0 / 9.0) * (fDouble - 32)
        celcius.setText(cDouble.toString)
      }
    })
    applyLayoutData(fahrenheitToCelcius)

    val celciusToFahrenheit = new Button(this, SWT.PUSH)
    celciusToFahrenheit.setText("Celcius -> Fareinheight")
    celciusToFahrenheit.addSelectionListener(new SelectionAdapter() {
      override def widgetSelected(e: SelectionEvent) = {
        val cDouble = parseDouble(celcius.getText())
        val fDouble = (9.0 / 5.0) * cDouble + 32
        fahrenheit.setText(fDouble.toString)
      }
    })
    applyLayoutData(celciusToFahrenheit)
  }
}