@SuppressWarnings("unchecked")
<...>
Map<String,String> dataMap =  (Map<String,String>) tcp().getData().getBodyAs(Map.class);
<...>

public final class DataHelper
<...>
@SuppressWarnings("unchecked")
public Map<String,String> getDataMapFromBody (TCP tcp) {
    return (Map<String,String>) tcp().getData().getBodyAs(Map.class);
}