Method in RequestContext interface containing Map as return type

Question

Am getting error while trying to do this. Am using gwt2.5 and requestfactory.

My server class looks like this:

public class RuleConfiguration {

    public static Map<Long, List<Operator>> getDataTypeOperatorMappings() {
        return DataTypeOperatorMappingHelper.getInstance().getValidDataTypeToOperatorMappings();
    }
}

And corresponding RequestContextClass looks like this

import java.util.List;
import java.util.Map;


@Service( value = RuleConfiguration.class )
public interface RuleRequestContext extends RequestContext {

    Request<Map<Long, List<OperatorProxy>>> getDataTypeOperatorMappings();
}

But here am getting an error saying The type java.util.Map<"map signature"> cannot be used here

What is my mistake here? Kindly help. Thanks.

Answer 1

If you look here https://developers.google.com/web-toolkit/doc/latest/DevGuideRequestFactory It doesn't list Map as a transportable type - only List and Set. I had this problem once and solved it by breaking the map into two ArrayList where the index of one was the data for the other.