[Dozer 5.5.1] Bad non-cumulative orphan removals in Lists

Using dozer 5.5.1 from Maven repository.

Calling dozerBeanMapper.map(stringHolder0, stringHolder1);. Both argument objects are pre-initialized and are the same Class. Both objects wrap their own instance of List<String> strings;. Dozer is configured to map the strings field non-cumulative and to remove-orphans.

When mapping "1", "2" to "1", "2", the result is empty. When mapping "1", "3" to "1", "2", the result is "3".

Are list elements considered orphaned, although they are not? Please see attached unit test for illustration purposes.

org.test.ListHolder - simple string list wrapper

public class ListHolder {
    List<String> strings;

    public List<String> getStrings() {
        return strings;
    }

    public void setStrings(List<String> strings) {
        this.strings = strings;
    }
}

Failing unit test for illustration purposes:

public class MapperTest {

    DozerBeanMapper dozerBeanMapper;

    @Before
    public void init() {        
        dozerBeanMapper = new DozerBeanMapper();
        dozerBeanMapper.setMappingFiles(Arrays.asList("dozer-list-mapping.xml"));
    }

    @Test
    public void test00() {

        List<String> arrayList0 = new ArrayList<String>();
        arrayList0.add("1");
        arrayList0.add("2");

        ListHolder stringHolder0 = new ListHolder();
        stringHolder0.setStrings(arrayList0);

        List<String> arrayList1 = new ArrayList<String>();
        arrayList1.add("1");
        arrayList1.add("2");

        ListHolder stringHolder1 = new ListHolder();
        stringHolder1.setStrings(arrayList1);

        dozerBeanMapper.map(stringHolder0, stringHolder1);
        List<String> strings = stringHolder1.getStrings();

        // fails - strings is empty
        assertEquals(2,strings.size());     
        assertEquals("1",strings.get(0));
        assertEquals("2",strings.get(1));
    }

    @Test
    public void test01() {

        List<String> arrayList0 = new ArrayList<String>();
        arrayList0.add("1");
        arrayList0.add("3");

        ListHolder stringHolder0 = new ListHolder();
        stringHolder0.setStrings(arrayList0);

        List<String> arrayList1 = new ArrayList<String>();
        arrayList1.add("1");
        arrayList1.add("2");

        ListHolder stringHolder1 = new ListHolder();
        stringHolder1.setStrings(arrayList1);

        dozerBeanMapper.map(stringHolder0, stringHolder1);
        List<String> strings = stringHolder1.getStrings();

        // fails - strings contains only 1 element -> "3"
        assertEquals(2,strings.size());     
        assertEquals("1",strings.get(0));
        assertEquals("2",strings.get(1));
    }
}

dozer-list-mapping.xml:

<?xml version="1.0" encoding="UTF-8"?>
<mappings xmlns="http://dozer.sourceforge.net" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://dozer.sourceforge.net http://dozer.sourceforge.net/schema/beanmapping.xsd">
    <mapping map-null="false">
        <class-a>org.test.ListHolder</class-a>
        <class-b>org.test.ListHolder</class-b>
        <field relationship-type="non-cumulative" remove-orphans="true">
            <a>strings</a>
            <b>strings</b>
        </field>
    </mapping>
</mappings>

java -version

java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

[joseanibl138]

Nodoby knows how to fix this yet? This issue is a pretty big problem. - Also: Why the heck is ‘non-cumulative’ and ‘remove-orphans’ not the default globally? I had to bleed my brain with workarounds, I think it would be a great idea to make these changes.

[Robbe64]

Will this be fixed sometime?

@lihue Could you please provide your workaround?