code: public Optional<JClassType> getMixInAnnotations( JType type ) {
          return Optional.fromNullable( mixInAnnotations.get( type.getQualifiedSourceName() ) );
      }
docs: Return the mixin type for the given type
  
  @param type a {@link com.google.gwt.core.ext.typeinfo.JType} object.
  @return a {@link com.google.gwt.thirdparty.guava.common.base.Optional} object.