component.declareOutputFields(getter);
Map<String, StreamInfo> declaration = getter.getFieldsDeclaration();
if(declaration.size()!=1) {
throw new RuntimeException("Trident only supports components that emit a single stream");
}
StreamInfo si = declaration.values().iterator().next();
if(si.is_direct()) {
throw new RuntimeException("Trident does not support direct streams");
}
return new Fields(si.get_output_fields());
}