mapperService.documentMapperParser().putRootTypeParser(ExternalRootMapper.CONTENT_TYPE,
new ExternalRootMapper.TypeParser());
mapperService.documentMapperParser().putTypeParser(RegisterExternalTypes.EXTERNAL,
new ExternalMapper.TypeParser(RegisterExternalTypes.EXTERNAL, "foo"));
DocumentMapper documentMapper = mapperService.documentMapperParser().parse(
XContentFactory.jsonBuilder().startObject().startObject("type")
.startObject(ExternalRootMapper.CONTENT_TYPE)
.endObject()
.startObject("properties")
.startObject("field").field("type", "external").endObject()