QueryIterator.cpp

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/*  Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.

    This file is part of the TerraLib - a Framework for building GIS enabled applications.

    TerraLib is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License,
    or (at your option) any later version.

    TerraLib 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TerraLib. See COPYING. If not, write to
    TerraLib Team at <terralib-team@terralib.org>.
 */

/*!
  \file QueryIterator.cpp

  \brief 
*/

// Terralib Includes
#include "../../common/Translator.h"
#include "../../common/StringUtils.h"
#include "../../dataaccess/dataset/DataSet.h"
#include "../../dataaccess/datasource/DataSource.h"
#include "../../dataaccess/query_h.h"
#include "../core/GraphMetadata.h"
#include "../Config.h"
#include "../Exception.h"
#include "../Globals.h"
#include "QueryIterator.h"

te::graph::QueryIterator::QueryIterator(te::graph::AbstractGraph* g) : 
  te::graph::AbstractIterator(g),
  m_exp(0)
{
}

te::graph::QueryIterator::QueryIterator(te::graph::AbstractGraph* g, te::da::Expression* e) : 
  te::graph::AbstractIterator(g),
  m_exp(e)
{
}

te::graph::QueryIterator::~QueryIterator()
{
}

te::graph::Vertex* te::graph::QueryIterator::getFirstVertex()
{
  if(m_graph == 0 || m_graph->getMetadata() == 0)
  {
    throw Exception(TE_TR("Invalid graph pointer."));
  }

  if(m_exp == 0)
  {
    throw Exception(TE_TR("Expression not defined."));
  }

  if(m_vertexQuery.get())
  {
    if(m_vertexQuery->moveFirst())
    {
      int id = m_vertexQuery->getInt32(Globals::sm_tableVertexModelAttrId);

      return m_graph->getVertex(id);
    }
  }

  //create a query to get eache vertex id
  std::string tableName = m_graph->getMetadata()->getVertexTableName();

  te::da::Field* f = new te::da::Field(new te::da::PropertyName(Globals::sm_tableVertexModelAttrId));
  te::da::Fields* fields = new te::da::Fields;
  fields->push_back(f);

  te::da::FromItem* t = new te::da::DataSetName(tableName);
  te::da::From* from = new te::da::From;
  from->push_back(t);

  te::da::Where* w = new te::da::Where(m_exp);

  te::da::OrderByItem* obItem = new te::da::OrderByItem(new te::da::PropertyName(Globals::sm_tableVertexModelAttrId));
  te::da::OrderBy* ob = new te::da::OrderBy();
  ob->push_back(obItem);

  te::da::Select select(fields, from, w, ob);

  m_vertexQuery.reset(0);
  m_vertexQuery = m_graph->getMetadata()->getDataSource()->query(select);

  if(m_vertexQuery.get() == 0)
  {
    throw Exception(TE_TR("Iterator not initialized."));
  }

  int id;

  if(m_vertexQuery->moveNext())
  {
    id = m_vertexQuery->getInt32(Globals::sm_tableVertexModelAttrId);
  }
  else
  {
    return 0;
  }

  return m_graph->getVertex(id);
}

te::graph::Edge* te::graph::QueryIterator::getFirstEdge()
{
  if(m_graph == 0 || m_graph->getMetadata() == 0)
  {
    throw Exception(TE_TR("Invalid graph pointer."));
  }

  if(m_edgeQuery.get())
  {
    if(m_edgeQuery->moveFirst())
    {
      int id = m_edgeQuery->getInt32(Globals::sm_tableEdgeModelAttrId);

      return m_graph->getEdge(id);
    }
  }

  //create a query to get eache vertex id
  std::string edgeTable = m_graph->getMetadata()->getEdgeTableName();
  std::string vertexAttrTalbe = m_graph->getMetadata()->getVertexTableName();

  te::da::Field* f = new te::da::Field(new te::da::PropertyName(Globals::sm_tableEdgeModelAttrId));
  te::da::Fields* fields = new te::da::Fields;
  fields->push_back(f);

  //from
  te::da::From* from = new te::da::From;

  te::da::FromItem* fi1 = new te::da::DataSetName(edgeTable, "edges");
  from->push_back(fi1);
  te::da::FromItem* fi2 = new te::da::DataSetName(vertexAttrTalbe, "v1");
  from->push_back(fi2);
  te::da::FromItem* fi3 = new te::da::DataSetName(vertexAttrTalbe, "v2");
  from->push_back(fi3);

  std::string edgeIdStr = "edges.";
              edgeIdStr += Globals::sm_tableEdgeModelAttrId;

  std::string vertexFrom = "edges.";
              vertexFrom += Globals::sm_tableEdgeModelAttrVFrom;

  std::string vertexTo = "edges.";
              vertexTo += Globals::sm_tableEdgeModelAttrVTo;

  std::string v1Id = "v1.";
              v1Id += Globals::sm_tableVertexModelAttrId;

  std::string v2Id = "v2.";
              v2Id += Globals::sm_tableVertexModelAttrId;

  //where
  te::da::Field* fvf = new te::da::Field(vertexFrom);
  te::da::Field* fv1id = new te::da::Field(v1Id);
  te::da::Expression* exp1 = new te::da::EqualTo(fvf->getExpression(), fv1id->getExpression());

  te::da::Field* fvt = new te::da::Field(vertexTo);
  te::da::Field* fv2id = new te::da::Field(v2Id);
  te::da::Expression* exp2 = new te::da::EqualTo(fvt->getExpression(), fv2id->getExpression());

  te::da::And* anda = new te::da::And(exp1, exp2);

  te::da::And* andd = new te::da::And(anda, m_exp);

  te::da::Where* w = new te::da::Where(andd);

  te::da::OrderByItem* obItem = new te::da::OrderByItem(new te::da::PropertyName(Globals::sm_tableEdgeModelAttrId));
  te::da::OrderBy* ob = new te::da::OrderBy();
  ob->push_back(obItem);

  te::da::Select select(fields, from, w, ob);

  m_edgeQuery.reset(0);
  m_edgeQuery = m_graph->getMetadata()->getDataSource()->query(select);

  if(m_edgeQuery.get() == 0)
  {
    throw Exception(TE_TR("Iterator not initialized."));
  }

  int id;

  if(m_edgeQuery->moveNext())
  {
    id = m_edgeQuery->getInt32(Globals::sm_tableEdgeModelAttrId);
  }
  else
  {
    return 0;
  }

  return m_graph->getEdge(id);
}