Question

How do you map a single field into a List / Collection in Dozer?

class SrcFoo {
    private String id;
    private List<SrcBar> bars;
}

class SrcBar {
    private String name;
}

Here are my destination objects:

class DestFoo {
    private List<DestBar> destBars;
}

class DestBar {
    private String fooId; // Populated by SrcFoo.id
    private String barName;
}

I want all DestBar.fooId (entire list of DestBars) to be populated with SrcFoo.id

This question is similar to this one posted here, expect I want to map my single field to every item in the list. Dozer: map single field to Set

I tried the following, but it only populated DestBar.fooId for the first item in the list.

<mapping> 
     <class-a>SrcFoo</class-a> 
     <class-b>DestFoo</class-b> 
     <field>
         <a>bars</a>
         <b>destBars</b>
     </field> 
     <field>
         <a>id</a>
         <b>destBars.fooId</b> <!-- same affect as destBars[0].fooId ? -->
     </field> 
</mapping>

Answer 1

Dozer does not support that type of mapping. In order to do that type of mapping, you would have to know the indexes on your Collection (static mapping).
This a Job for a custom converter, Create a converter of String to List (of DestBar) like this:

public class YourConverter extends DozerConverter<String, List>

Implement the mapping logic in your converter (Just set the String Id where required) and configure your dozer file like this:

<mapping> 
     <class-a>SrcFoo</class-a> 
     <class-b>DestFoo</class-b> 
     ...
     <field custom-converter="yourpackage.YourConverter">
         <a>id</a>
         <b>destBars</b>
     </field> 
</mapping>