Building a general DynamoDBMarshalling for enums

Question

I\'m using Amazon Web Services SDK for Java for DynamoDB; trying to suffice the interface for @DynamoDBMarshalling:

Class

        

Answer 1

The following worked fine to me:

The Marshaller:

public class EnumMarshaller implements DynamoDBMarshaller<Enum> {
    @Override
    public String marshall(Enum getterReturnResult) {
        return getterReturnResult.name();
    }

    @Override
    public Enum unmarshall(Class<Enum> clazz, String obj) {
        return Enum.valueOf(clazz, obj);
    }
}

In my table class with an enum:

@DynamoDBMarshalling(marshallerClass=EnumMarshaller.class)
@DynamoDBAttribute(attributeName = "MyEnum")
public MyEnum getMyEnum() {
   return myEnum;
}

Answer 2

I worked around this problem by sub-classing the JsonMarshaller with a specific class type:

public class FooMarshaller extends JsonMarshaller<Foo>
{
    // No impl required
}

Then the marshalling annotation is added to the data property like:

@DynamoDBMarshalling(marshallerClass = FooMarshaller.class)
public Set<Foo> getFoos()
{
    return foos;
}

A pain if you have to add many class types, but it works.