136 lines
3.1 KiB
C++
136 lines
3.1 KiB
C++
/*
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----
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This file is part of SECONDO.
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Copyright (C) 2021,
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Faculty of Mathematics and Computer Science,
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Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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//[$][\$]
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*/
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#ifndef _RESULT_ITERATOR_GENERIC_H_
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#define _RESULT_ITERATOR_GENERIC_H_
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#include "Attribute.h"
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#include "NestedList.h"
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#include "StandardTypes.h"
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#include "Algebra.h"
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#include "Algebras/Relation-C++/RelationAlgebra.h"
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#include <vector>
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#include <string>
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#include <boost/log/trivial.hpp>
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namespace BasicEngine {
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/*
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1 Class ~ResultIteratorGeneric~
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A database independend iterator for query results
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*/
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class ResultIteratorGeneric {
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/*
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1.1 Public Methods
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*/
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public:
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ResultIteratorGeneric(ListExpr &type) {
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ListExpr numType = nl->Second(
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SecondoSystem::GetCatalog()->NumericType(type));
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tt = new TupleType(numType);
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basicTuple = new Tuple(tt);
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// build attributeInstances for each type
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ListExpr attrList = nl->Second(nl->Second(type));
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while(!nl->IsEmpty(attrList)){
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ListExpr attrType = nl->Second(nl->First(attrList));
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attrList = nl->Rest(attrList);
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int algId;
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int typeId;
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std::string tname;
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if(! ((SecondoSystem::GetCatalog())->LookUpTypeExpr(attrType,
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tname, algId, typeId))) {
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BOOST_LOG_TRIVIAL(error) << "Type: "
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<< nl->ToString(attrType)
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<< "Unable to find attribute in catalog";
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ready = false;
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}
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Word w = am->CreateObj(algId,typeId)(attrType);
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attributeInstances.push_back(static_cast<Attribute*>(w.addr));
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}
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}
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virtual ~ResultIteratorGeneric() {
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if(tt != nullptr) {
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tt -> DeleteIfAllowed();
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tt = nullptr;
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}
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if(basicTuple != nullptr) {
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basicTuple -> DeleteIfAllowed();
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basicTuple = nullptr;
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}
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for(size_t i=0; i<attributeInstances.size(); i++){
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delete attributeInstances[i];
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}
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attributeInstances.clear();
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}
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/*
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1.1.1 Returns whether or not a tuple is available
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*/
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virtual bool hasNextTuple() = 0;
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/*
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1.1.2 Get the next tuple
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*/
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virtual Tuple* getNextTuple() = 0;
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protected:
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bool ready = true;
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ListExpr type;
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TupleType* tt = nullptr;
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Tuple* basicTuple = nullptr;
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std::vector<Attribute*> attributeInstances;
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private:
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}; // Class
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}; // Namespace
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#endif |