title: Mapping two values to a single property with Orika
body: <p>Suppose I have a source object, containing two properties, a and b like this:</p>
  
  <pre><code>public class Source {
      String a, b;
  }
  </code></pre>
  
  <p>and a target object with one property c:</p>
  
  <pre><code>public class Target {
      String c;
  }
  </code></pre>
  
  <p>I'd like to define a mapping that will:</p>
  
  <ol>
  <li>map property a to c if a is not null</li>
  <li>map property b to c if b is not null</li>
  </ol>
  
  <p>I thought it would be possible with a mapper with mapNulls set to false:</p>
  
  <pre><code>factory.registerClassMap(factory.classMap(Source.class, Target.class).field("a", "c").field("b", "c").mapNulls(false));
  </code></pre>
  
  <p>However, when I set property a to a non-null value and leave property b to null, the mapping results in a target object with c set to null.</p>
  
  <p>Have I misunderstood the purpose of mapNulls?</p>