java - Dozer bidirectional mapping (String, String) with custom comverter impossible? -

i have dozer mapping custom converter:

<mapping>     <class-a>com.xyz.customer</class-a>     <class-b>com.xyz.customerdao</class-b>     <field custom-converter="com.xyz.dozeremptystring2nullconverter">         <a>customername</a>         <b>customername</b>     </field> </mapping> 

and converter:

public class dozeremptystring2nullconverter extends dozerconverter<string, string> {      public dozeremptystring2nullconverter() {         super(string.class, string.class);     }      public string convertfrom(string source, string destination) {         string ret = null;         if (source != null) {             if (!source.equals(""))             {                 ret = stringformatter.wildcard(source);             }          }         return ret;     }      public string convertto(string source, string destination) {         return source;     } } 

when call mapper in 1 direction (customer -> customerdao) method 'convertto' called.

since dozer able handle bi-directional mapping, expect that, call mapper in opposite direction, method 'convertfrom' called.

but method convertto never called.

i suspect problem is, both types strings - how can make work?

as workaround created 2 one-way-mapping, standard solution, or behavior bug?

yes, problem source , destination classes same. here dozer source dozerconverter:

  public object convert(object existingdestinationfieldvalue, object sourcefieldvalue, class<?> destinationclass, class<?> sourceclass) {     class<?> wrappeddestinationclass = classutils.primitivetowrapper(destinationclass);     class<?> wrappedsourceclass = classutils.primitivetowrapper(sourceclass);      if (prototypea.equals(wrappeddestinationclass)) {       return convertfrom((b) sourcefieldvalue, (a) existingdestinationfieldvalue);     } else if (prototypeb.equals(wrappeddestinationclass)) {       return convertto((a) sourcefieldvalue, (b) existingdestinationfieldvalue);     } else if (prototypea.equals(wrappedsourceclass)) {       return convertto((a) sourcefieldvalue, (b) existingdestinationfieldvalue);     } else if (prototypeb.equals(wrappedsourceclass)) {       return convertfrom((b) sourcefieldvalue, (a) existingdestinationfieldvalue);     } else if (prototypea.isassignablefrom(wrappeddestinationclass)) {       return convertfrom((b) sourcefieldvalue, (a) existingdestinationfieldvalue);     } else if (prototypeb.isassignablefrom(wrappeddestinationclass)) {       return convertto((a) sourcefieldvalue, (b) existingdestinationfieldvalue);     } else if (prototypea.isassignablefrom(wrappedsourceclass)) {       return convertto((a) sourcefieldvalue, (b) existingdestinationfieldvalue);     } else if (prototypeb.isassignablefrom(wrappedsourceclass)) {       return convertfrom((b) sourcefieldvalue, (a) existingdestinationfieldvalue);     } else {       throw new mappingexception("destination type (" + wrappeddestinationclass.getname()           + ") not accepted custom converter ("            + this.getclass().getname() + ")!");     }    } 

instead of using convertfrom , convertto methods (which part of new api), original way in have implement customconverter.convert shown in tutorial.