@Override
public TupleEntryIterator openForRead(FlowProcess<Properties> flowProcess, ScrollQuery input) throws IOException {
if (input == null) {
// get original copy
Settings settings = CascadingUtils.addDefaultsToSettings(CascadingUtils.extractOriginalProperties(flowProcess.getConfigCopy()), tapProperties, log);
// will be closed by the query is finished
RestRepository client = new RestRepository(settings);
Field mapping = client.getMapping();
Collection<String> fields = CascadingUtils.fieldToAlias(settings, getSourceFields());
// validate if possible
FieldPresenceValidation validation = settings.getFieldExistanceValidation();
if (validation.isRequired()) {
MappingUtils.validateMapping(fields, mapping, validation, log);
}
input = QueryBuilder.query(settings).fields(StringUtils.concatenateAndUriEncode(fields, ",")).build(client,
new ScrollReader(new JdkValueReader(), mapping, settings.getReadMetadata(), settings.getReadMetadataField()));
}
return new TupleEntrySchemeIterator<Properties, ScrollQuery>(flowProcess, getScheme(), input, getIdentifier());
}