title: Setting a flag using a command-line argument with Argparse4j
body: <p>I am using <a href="http://argparse4j.sourceforge.net/" rel="nofollow noreferrer">argparse4j</a> to parse command line arguments. I want to add an argument that when present, sets a boolean to true, otherwise it defaults to false. I don't want to include the true or false in the argument, just the identifier, so it would look something like this when run:</p>
  
  <pre><code>java firstArg --enable-boolean
  </code></pre>
  
  <p><a href="https://stackoverflow.com/questions/9183936/boolean-argument-for-script">This answer</a> shows that in Python, I could set the <code>action</code> of the argument to store a true or false value like so:</p>
  
  <blockquote>
  <pre><code>parser.add_argument('-b', action='store_true', default=False)
  </code></pre>
  </blockquote>
  
  <p>How can I do the same thing in Java, using argparse4j?</p>