How can I get the number of selected item from an inputDialog which contains a comboBox?

Question

Using this part of code I am getting a list of urls and add them as items into the comboBox of an JOptionPane InputDialog:

def getURL() {
    WebDriver wDriver = DriverFactory.getWebDriver()
    List<WebElement> wElements = wDriver.findElements(By.xpath('//a'))

    List<String> hrefs = []
    
    for (WebElement wElement : wElements) {
        String href = wElement.getAttribute("href")
        if (href != null) {
            hrefs.add(href)
        }
    }
        
    String message_result = JOptionPane.showInputDialog(null, "Message Text", "Message Title", JOptionPane.INFORMATION_MESSAGE, null, hrefs.toArray(), hrefs.toArray()[0])
    println('You have select: ' + message_result)
}

As it is now, it will print the selected url as string:

You have select: https://www.google.com

What I want to do is to print the selected url as the number of selected item. For example, instead of You have select: https://www.google.com, I want to get this:

You have select: 4