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#ifndef _QTJOINITERATOR_
#define _QTJOINITERATOR_
#ifndef CPPSTDLIB
#include <ospace/string.h> // STL<ToolKit>
#else
#include <string>
#endif
#include "qlparser/qtiterator.hh"
#include "qlparser/qtoperation.hh"
/*
* This file is part of rasdaman community.
*
* Rasdaman community 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 3 of the License, or
* (at your option) any later version.
*
* Rasdaman community 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 rasdaman community. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Peter Baumann /
rasdaman GmbH.
*
* For more information please see <http://www.rasdaman.org>
* or contact Peter Baumann via <baumann@rasdaman.com>.
*/
/*************************************************************
*
*
* COMMENTS:
*
************************************************************/
//@ManMemo: Module: {\bf qlparser}
/*@Doc:
An object of this class takes its inputs and computes a tupel for every element
of the cross product. The result is passed to the output stream.
The class represents the FROM part of a query.
*/
class QtJoinIterator : public QtIterator
{
public:
/// default constructor
QtJoinIterator();
/// constructor getting a pointer to the parent
QtJoinIterator( QtNode* node );
/// virtual destructor
virtual ~QtJoinIterator();
/// prints the tree
virtual void printTree( int tab, std::ostream& s = std::cout, QtChildType mode = QT_ALL_NODES );
/// prints the algebraic expression
virtual void printAlgebraicExpression( std::ostream& s = std::cout );
//@Man: Operations of the ONC protocol:
//@{
///
void open();
///
QtDataList* next();
/**
According to the producer/consumer protocol of ONC streams, the {/tt next()}
method has to store the last tupel of the crossproduct and update it with a new
element everytime it is invoked. Than it makes a copy of the tupel and pass
it to the caller.
*/
///
void close();
///
void reset();
///
//@}
//@Man: Read/Write methods:
//@{
///
//inline virtual void setParents();
//@}
/// method for identification of nodes
inline virtual const QtNodeType getNodeType() const;
/// type checking
virtual const QtTypeTuple& checkType();
private:
/// inidicates if the output stream is empty or not
bool outputStreamIsEmpty;
/** The output stream is empty if at least one of the input streams is empty.
In that case, the cross product has no elements. This is indicated
by the variable {\tt outputStreamIsEmpty} which is set in the method
{\tt open()}.
*/
/// pointer to a copy of the last passed tupel
QtDataList* actualTupel;
/// attribute for identification of nodes
static const QtNodeType nodeType;
};
#include "qlparser/qtjoiniterator.icc"
#endif
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