/*

1.1 ~OperatorRead2~

This operator reads a tuple stream from a relation and requests its replica
from the ~DBService~ if the relation is not available locally. It allows passing
a function that is executed on the replica so that only the matching tuples have
to be transferred.

----
This file is part of SECONDO.

Copyright (C) 2017,
Faculty of Mathematics and Computer Science,
Database Systems for New Applications.

SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

SECONDO is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
----

*/
#ifndef ALGEBRAS_DBSERVICE_OperatorRead2_HPP_
#define ALGEBRAS_DBSERVICE_OperatorRead2_HPP_

#include "Operator.h"

namespace DBService {

/*

1.1.1 Operator Specification

*/

struct Read2Info: OperatorInfo
{
    Read2Info()
    {
        name = "read2";
        signature = "rel(tuple) x fun -> stream(tuple)";
        syntax = "read(rel, fun)";
        meaning = "read a tuple stream from a relation and fall back to the "
                  "replica provided by the DBService if necessary";
        example = "query myRelation read2[. filter[.Host = 'node2'] "
                "project[Host, Port]] consume";
        remark = "requires a DBService system";
        usesArgsInTypeMapping = false;
    }
};

/*

1.1.1 Class Definition

*/

class OperatorRead2
{
public:

/*

1.1.1.1 Type Mapping Function

*/
    static ListExpr mapType(ListExpr nestedList);

/*

1.1.1.1 Value Mapping Function

*/
    static int mapValue(Word* args,
                        Word& result,
                        int message,
                        Word& local,
                        Supplier s);
};

} /* namespace DBService */

#endif /* ALGEBRAS_DBSERVICE_OPERATORREAD_HPP_ */