DynamoDB mapping List of Enum

Question

Mapping an enum class in to DynamoDB object is really simple by using Custom Marshall. But how to map a List of Enum?

Enum class

public enum Transport {
SMS,EMAIL,ALL;
}

DynamoDB mapper

public class Campaign{
   private List<Transport> transport;

   @DynamoDBAttribute(attributeName = "transport")
   public List<Transport> getTransport() {
       return transport;
   }

   public void setTransport(List<Transport> transport) {
      this.transport = transport;
   }
}

Answer 1

I found the answer myself. I create a custom marshall like below.

public class TransportMarshaller implements DynamoDBMarshaller<List<Transport>> {

@Override
public String marshall(List<Transport> transports) {
    List<String>transportMap=new ArrayList<>();
    for(Transport transport:transports){
        transportMap.add(transport.name());
    }
    return transportMap.toString().replaceAll("\\[|\\]", "");//Save as comma separate value for the purpose of easiness to unmarshall
}

@Override
public List<Transport> unmarshall(Class<List<Transport>> aClass, String s) {
    List<String>map= Arrays.asList(s.split("\\s*,\\s*")); //split from comma and parse to List
    List<Transport>transports=new ArrayList<>();
    for (String st:map){
        transports.add(Transport.valueOf(st));
    }
    return transports;
}
}