title: check if Integer is Null or numeric in groovy?
body: <p>I have a service method and have to throw an error if method parameter is null/blank or not numeric.</p>
  
  <p>Caller is sending an Integer value but in called method how to check if it is numeric or null.</p>
  
  <p>ex:</p>
  
  <pre><code>def add(value1,value2){
   //have to check value1 is null/blank
   //check value1 is numeric
  
  }
  
  caller: class.add(10,20)
  </code></pre>
  
  <p>Any suggestions around would be appreciated.</p>