title: JCommander parameter validation aware of other parameters
body: <p>I'm using JCommander to parse command line params. I validate parameters using:</p>
  
  <pre><code>public class SomeClass implements IParameterValidator {
      public void validate(String name, String value) throws ParameterException { 
      ...
  }
  </code></pre>
  
  <p>I ran into edge cases, when it would be helpful if the block of code above could know what are the other command line params supplied for the application, not just that one. Is it possible with JCommander at all?</p>
  
  <p>I can achieve my goals with JCommander Commands, but this is not as flexible as the desired solution.</p>