Don't Map null entries from one list to another in Dozer

Question

Suppose I have following Class - structure ?

class A{
List<B> listB;
//getter and setter
}
class B{
String s;
//getter and setter
}
//objectOfA has listB = [null,objectOfB,null]
A a2 = dozermapper.map(objectOfA,A.class);

I want a2 contains listB=[objectOfB] only. not null elements of list.

How to do it in dozer?

Answer 1

You could write a simple converter, like this (uses new converter api, you can use old also):

public class Converter extends DozerConverter<List<B>, List<B>> {
  public Converter() {
    super(List.class, List.class);
  }

  public List<B> convertTo(List<B> source, List<B> destination) {
    List<B> result = new ArrayList<B>();
    for (B item : source) {
      if (item != null) {
          result.add(item); //or item copy, or whatever you want
      }
    }
    return result;
  }
} 

and then attach it to your mapping like this:

<mapping>
  <class-a>yourpackage.A</class-a>
  <class-b>yourpackage.A</class-b>    
  <field custom-converter="yourpackage.Converter">
      <a>listB</a>
      <b>listB</b>
  </field>
</mapping>