title: JAXB convert multiple attributes to one type while unmarshalling
body: <p>Image I have an element like this <code>&lt;someElement a="" b="" number="1" scale="meters"&gt;&lt;child/&gt;&lt;/someElement&gt;</code></p>
  
  <p>scale and number always appear together but they are not defined in one exclusive element.</p>
  
  <p>When unmarshalling the <code>someElement</code> element to a <code>SomeElement</code> java instance I want a single member in the <code>SomeElement</code> class to represent <code>number</code> and <code>scale</code>.</p>
  
  <p>At the moment both number and scale are attributes and then the <code>afterUnmarshall()</code> method is used for calculating one number.</p>
  
  <p>Is there a way to do this without having the two member fields size and scale? Maybe with a <code>XmlAdapter</code>? How would I use this in this case?</p>