Application: gvSIG desktop

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright (C) 2007-2020 gvSIG Association.

 *

 * This program 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.

 *

 * This program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

 * MA  02110-1301, USA.

 *

 * For any additional information, do not hesitate to contact us

 * at info AT gvsig.com, or visit our website www.gvsig.com.

 */

package org.gvsig.fmap.dal.store.jdbc2.spi;

import java.io.File;

import java.sql.Blob;

import java.sql.Clob;

import java.sql.Connection;

import java.sql.ResultSet;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import org.apache.commons.io.IOUtils;

import org.apache.commons.lang3.ArrayUtils;

import org.apache.commons.lang3.StringUtils;

import org.apache.commons.lang3.mutable.MutableBoolean;

import org.gvsig.expressionevaluator.Code;

import org.gvsig.expressionevaluator.ExpressionBuilder;

import org.gvsig.expressionevaluator.ExpressionEvaluatorLocator;

import org.gvsig.expressionevaluator.ExpressionEvaluatorManager;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.GeometryExpressionBuilderHelper.GeometrySupportType;

import org.gvsig.expressionevaluator.SymbolTable;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_EXISTS;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_FOREING_VALUE;

import org.gvsig.fmap.dal.DataTypes;

import org.gvsig.fmap.dal.SQLBuilder;

import org.gvsig.fmap.dal.exception.DataException;

import org.gvsig.fmap.dal.exception.InitializeException;

import org.gvsig.fmap.dal.feature.FeatureAttributeDescriptor;

import org.gvsig.fmap.dal.feature.FeatureQueryOrder;

import org.gvsig.fmap.dal.feature.FeatureType;

import org.gvsig.fmap.dal.feature.ForeingKey;

import org.gvsig.fmap.dal.feature.spi.FeatureProvider;

import org.gvsig.fmap.dal.feature.spi.SQLBuilderBase;

import org.gvsig.fmap.dal.resource.exception.AccessResourceException;

import org.gvsig.fmap.dal.resource.spi.ResourceConsumer;

import org.gvsig.fmap.dal.resource.spi.ResourceProvider;

import org.gvsig.fmap.dal.serverexplorer.filesystem.FilesystemStoreParameters;

import org.gvsig.fmap.dal.spi.DataServerExplorerProviderServices;

import org.gvsig.fmap.dal.spi.DataStoreProviderServices;

import org.gvsig.fmap.dal.spi.DataTransactionServices;

import org.gvsig.fmap.dal.store.db.DBHelper;

import org.gvsig.fmap.dal.store.jdbc.JDBCConnectionParameters;

import org.gvsig.fmap.dal.store.jdbc.JDBCLibrary;

import org.gvsig.fmap.dal.store.jdbc.JDBCNewStoreParameters;

import org.gvsig.fmap.dal.store.jdbc.JDBCResource;

import org.gvsig.fmap.dal.store.jdbc.JDBCServerExplorerParameters;

import org.gvsig.fmap.dal.store.jdbc.JDBCStoreParameters;

import org.gvsig.fmap.dal.store.jdbc.exception.JDBCCantFetchValueException;

import org.gvsig.fmap.dal.store.jdbc2.JDBCHelper;

import org.gvsig.fmap.dal.store.jdbc2.JDBCServerExplorer;

import org.gvsig.fmap.dal.store.jdbc2.JDBCStoreProvider;

import org.gvsig.fmap.dal.store.jdbc2.JDBCUtils;

import org.gvsig.fmap.dal.store.jdbc2.OperationsFactory;

import org.gvsig.fmap.dal.store.jdbc2.ResulSetControler;

import org.gvsig.fmap.dal.store.jdbc2.ResulSetControler.ResultSetEntry;

import org.gvsig.fmap.dal.store.jdbc2.impl.ResulSetControlerBase;

import org.gvsig.fmap.dal.store.jdbc2.spi.operations.OperationsFactoryBase;

import org.gvsig.fmap.geom.Geometry;

import org.gvsig.fmap.geom.GeometryLocator;

import org.gvsig.fmap.geom.GeometryManager;

import org.gvsig.tools.dispose.impl.AbstractDisposable;

import org.gvsig.tools.evaluator.Evaluator;

import org.gvsig.tools.exception.BaseException;

import org.gvsig.tools.exception.NotYetImplemented;

import org.gvsig.tools.visitor.VisitCanceledException;

import org.gvsig.tools.visitor.Visitor;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

@SuppressWarnings("UseSpecificCatch")

public class JDBCHelperBase extends AbstractDisposable implements ResourceConsumer, JDBCHelper {

  private static final boolean ALLOW_AUTOMATIC_VALUES = true;

  private static final String QUOTE_FOR_USE_IN_IDENTIFIERS = "\"";

  private static final String QUOTE_FOR_USE_IN_STRINGS = "'";

  private static final Logger LOGGER = LoggerFactory.getLogger(JDBCHelperBase.class);

  private ResulSetControler resulSetControler = null;

  // Quien ha creado este helper.

  // Se le reenviaran las notificaciones del recurso asociado al helper.

  private ResourceConsumer helperClient = null;

  private GeometryManager geometryManager = null;

  private JDBCConnectionParameters connectionParameters;

  private JDBCStoreProvider store;

  protected OperationsFactory operationsFactory = null;

  protected SRSSolver srssolver;

  protected FeatureType providerFeatureType = null;

  protected DataTransactionServices transaction;

  public JDBCHelperBase(JDBCConnectionParameters connectionParameters) {

        if (connectionParameters == null) {

            throw new IllegalArgumentException("Connection parameters can't be null.");

        }

        this.connectionParameters = connectionParameters;

        // If a particular treatment is required to convert SRS to the 

        // BBDD format, overwrite JDBCSRSsBase and use it instead of JDBCSRSsDumb.

        this.srssolver = new SRSSolverDumb(this);

    }

  protected void initialize(

          ResourceConsumer helperClient,

          JDBCConnectionParameters connectionParameters,

          JDBCStoreProvider store

  ) {

    this.store = store;

    this.helperClient = helperClient;

    this.connectionParameters = connectionParameters;

    initializeResource(connectionParameters);

  }

  protected String getResourceType() {

    return JDBCResource.NAME;

  }

  @Override

  public String getProviderName() {

    return JDBCLibrary.NAME;

  }

  @Override

  public GeometrySupportType getGeometrySupportType() {

    // El proveedor generico de JDBC guadara las geoemtrias como WKT

    return GeometrySupportType.WKT;

  }

    /**

     * @return the providerFeatureType

     */

  @Override

    public FeatureType getProviderFeatureType() {

        return providerFeatureType;

    }

    /**

     * @param providerFeatureType the providerFeatureType to set

     */

  @Override

    public void setProviderFeatureType(FeatureType providerFeatureType) {

        this.providerFeatureType = providerFeatureType;

    }

  @Override

  public boolean hasSpatialFunctions() {

    // Por defecto el proveedor generico de JDBC asume que la BBDD no 

    // tiene soporte para funciones espaciales.

    return false;

  }

  @Override

  public boolean allowNestedOperations() {

    return false;

  }

  @Override

  public boolean canWriteGeometry(int geometryType, int geometrySubtype) {

    // Como va a guardar las geometrias en WKT, puede escribirlas todas.

    return true;

  }

  @Override

  public JDBCSQLBuilderBase createSQLBuilder() {

    return new JDBCSQLBuilderBase(this);

  }

  @Override

  public String getQuoteForIdentifiers() {

    return QUOTE_FOR_USE_IN_IDENTIFIERS;

  }

  @Override

  public boolean allowAutomaticValues() {

    return ALLOW_AUTOMATIC_VALUES;

  }

  @Override

  public boolean supportOffsetInSelect() {

    // Asumimos que la BBDD soporta OFFSET

    return true;

  }

  @Override

  public String getQuoteForStrings() {

    return QUOTE_FOR_USE_IN_STRINGS;

  }

  protected boolean supportCaller(Code.Callable caller) {

    if (StringUtils.equalsIgnoreCase(caller.name(), "FOREING_VALUE")) {

      return true;

    }

    Function function = caller.function();

    if (function == null) {

      return false;

    }

    if (!function.isSQLCompatible()) {

      return false;

    }

    if (!this.hasSpatialFunctions()) {

      if (StringUtils.equalsIgnoreCase(function.group(), Function.GROUP_OGC)) {

        return false;

      }

    }

    return true;

  }

  @Override

  public boolean supportFilter(final FeatureType type, Evaluator filter) {

    // No podemos filtrar cuando:

    // - Hay una subquery especificada en los parametros 

    // - Si hay un filtro y el getSQL devuelbe null.

    // - Si se esta usando alguna funcion no-sql en el getSQL

    // - Si se estan usando funciones OGC y no soportamos funciones espaciales

    // - Si se esta usando algun campo calculado en la expresion de filtro.

    // 

    // Un proveedor especifico podria sobreescribir el metodo,

    // para hilar mas fino al comprobar si soporta el filtro o no.

    //

    if (this.useSubquery()) {

      // Se esta usando una subquery en los parametros de acceso a la

      // BBDD, asi que no podemos filtrar.

      return false;

    }

    if (filter == null) {

      // No hay que filtrar nada, asi que se p?ede.

      return true;

    }

    String sql = filter.getSQL();

    if (StringUtils.isEmpty(sql)) {

      // Hay un filtro, pero la SQL es null, con lo que no podemos

      // filtrar por el.

      return false;

    }

    // Ahora vamos a comprobar que las funciones que se usan son 

    // compatibles sql, y que no se usan funciones OGC si el 

    // proveedor dice que no soporta funciones espaciales.

    // Tambien comprobaremos que el filtro no usa ningun campo calculado.

    final MutableBoolean isCompatible = new MutableBoolean(true);

    ExpressionEvaluatorManager manager = ExpressionEvaluatorLocator.getManager();

    Code code = manager.compile(sql);

    SymbolTable symbolTable = manager.createSymbolTable();

    code.link(symbolTable);

    try {

      code.accept(new Visitor() {

        @Override

        public void visit(Object code_obj) throws VisitCanceledException, BaseException {

          Code code = (Code) code_obj;

          switch (code.code()) {

            case Code.CALLABLE:

              Code.Callable caller = (Code.Callable) code;

              if (!supportCaller(caller)) {

                isCompatible.setValue(false);

                throw new VisitCanceledException();

              }

              break;

            case Code.IDENTIFIER:

              Code.Identifier identifier = (Code.Identifier) code;

              if (type != null) {

                FeatureAttributeDescriptor attrdesc = type.getAttributeDescriptor(identifier.name());

                if (attrdesc != null) {

                  if (attrdesc.isComputed()) {

                    isCompatible.setValue(false);

                    throw new VisitCanceledException();

                  }

                }

              }

              break;

          }

        }

      });

    } catch (VisitCanceledException ex) {

      // Do nothing

    } catch (Exception ex) {

      LOGGER.warn("Can't calculate if is SQL compatible.", ex);

    }

    return isCompatible.booleanValue();

  }

  @Override

  public boolean supportOrder(FeatureType type, FeatureQueryOrder order) {

    if (this.useSubquery()) {

      return false;

    }

    if (order == null) {

      return true;

    }

    for (FeatureQueryOrder.FeatureQueryOrderMember member : order.members()) {

      if (member.hasEvaluator()) {

        if (!this.supportFilter(type, member.getEvaluator())) {

          return false;

        }

      }

    }

    return true;

  }

  @Override

  public OperationsFactory getOperations() {

    if (this.operationsFactory == null && !isClosed()) {

      this.operationsFactory = new OperationsFactoryBase(this);

    }

    return operationsFactory;

  }

  protected void initializeResource(JDBCConnectionParameters params) {

//        Object[] resourceParams = new Object[]{

//            params.getUrl(),

//            params.getHost(),

//            params.getPort(),

//            params.getDBName(),

//            params.getUser(),

//            params.getPassword(),

//            params.getJDBCDriverClassName()

//        };

//

//        try {

//            ResourceManagerProviderServices manager

//                    = (ResourceManagerProviderServices) DALLocator.getResourceManager();

//            JDBCResource resource = (JDBCResource) manager.createAddResource(

//                    this.getResourceType(),

//                    resourceParams

//            );

//            this.resource = resource;

//            this.resource.addConsumer(this);

//        } catch (InitializeException ex) {

//            logger.trace("Can't initialize resource (" + ArrayUtils.toString(resourceParams) + ").", ex);

//            throw new RuntimeException("Can't initialize resource (" + ArrayUtils.toString(resourceParams) + ").", ex);

//        }

  }

  @Override

  public String getSourceId() {

    return this.store.getSourceId();

  }

  @Override

  public JDBCResource getResource() {

    return null;

//        return this.resource;

  }

  @Override

  public Connection getConnection() throws AccessResourceException {

    throw new NotYetImplemented();

  }

  @Override

  public Connection getConnectionWritable() throws AccessResourceException {

    return this.getConnection();

  }

  @Override

  public String getConnectionURL() {

    return null;

  }

  @Override

  public JDBCConnectionParameters getConnectionParameters() {

    return connectionParameters;

  }

  @Override

  public void closeConnection(Connection connection) {

      JDBCUtils.close(connection);

  }

  @Override

  public void closeConnectionQuietly(Connection connection) {

      JDBCUtils.closeQuietly(connection);

  }

  @Override

  protected void doDispose() throws BaseException {

    JDBCUtils.closeQuietly(this);

  }

  @Override

  public void close() throws Exception {

    JDBCUtils.closeQuietly(this.resulSetControler);

    this.resulSetControler = null;

    this.operationsFactory = null;

    this.srssolver = null;

    this.connectionParameters = null;

    this.helperClient = null;

    this.geometryManager = null;

    this.providerFeatureType = null;

    this.store = null;

  }

  public boolean isClosed() {

      return this.srssolver == null;

  }

  @Override

  public boolean closeResourceRequested(ResourceProvider resource) {

    return this.helperClient.closeResourceRequested(resource);

  }

  @Override

  public void resourceChanged(ResourceProvider resource) {

    this.helperClient.resourceChanged(resource);

  }

  @Override

  public GeometryManager getGeometryManager() {

    if (this.geometryManager == null) {

      this.geometryManager = GeometryLocator.getGeometryManager();

    }

    return this.geometryManager;

  }

  @Override

  public ResulSetControler getResulSetControler() {

    if (this.resulSetControler == null) {

      this.resulSetControler = new ResulSetControlerBase(this);

    }

    return this.resulSetControler;

  }

  @Override

  public void fetchFeature(FeatureProvider feature, ResultSetEntry rs) throws DataException {

    fetchFeature(feature, rs.get(), rs.getColumns(), rs.getExtraValueNames());

  }

  @Override

  public void fetchFeature(FeatureProvider feature, ResultSet rs, FeatureAttributeDescriptor[] columns, String[] extraValueNames) throws DataException {

    Object value;

    try {

      int rsIndex = 1;

      for (FeatureAttributeDescriptor column : columns) {

        switch (column.getType()) {

          case DataTypes.GEOMETRY:

            value = this.getGeometryFromColumn(rs, rsIndex++);

            break;

          default:

            value = rs.getObject(rsIndex++);

            if (value instanceof Blob) {

              Blob blob = (Blob) value;

              value = blob.getBytes(1, (int) blob.length());

              blob.free();

            } else if(value instanceof Clob) {

              Clob clob = (Clob) value;

              value = new String(IOUtils.toCharArray(clob.getCharacterStream()));

              clob.free();

          }

        }

        feature.set(column.getIndex(), value);

      }

      if (ArrayUtils.isNotEmpty(extraValueNames)) {

        feature.setExtraValueNames(extraValueNames);

        for (int index = 0; index < extraValueNames.length; index++) {

          value = rs.getObject(rsIndex++);

          if (value instanceof Blob) {

            Blob blob = (Blob) value;

            value = blob.getBytes(0, (int) blob.length());

            blob.free();

          }

          feature.setExtraValue(index, value);

        }

      }

    } catch (Exception ex) {

      throw new JDBCCantFetchValueException(ex);

    }

  }

  @Override

  public Geometry getGeometryFromColumn(ResultSetEntry rs, int index) throws DataException {

    return getGeometryFromColumn(rs.get(), index);

  }

  @Override

  public Geometry getGeometryFromColumn(ResultSet rs, int index) throws DataException {

    try {

      Object value;

      switch (this.getGeometrySupportType()) {

        case NATIVE:

        case WKB:

          value = rs.getBytes(index);

          if (value == null) {

            return null;

          }

          return this.getGeometryManager().createFrom((byte[]) value);

        case EWKB:

          value = rs.getBytes(index);

          if (value == null) {

            return null;

          }

          return this.getGeometryManager().createFrom((byte[]) value);

        case WKT:

        default:

          value = rs.getString(index);

          if (value == null) {

            return null;

          }

          return this.getGeometryManager().createFrom((String) value);

      }

    } catch (Exception ex) {

      throw new JDBCCantFetchValueException(ex);

    }

  }

  @Override

  public FeatureProvider createFeature(FeatureType featureType) throws DataException {

    return this.store.getStoreServices().createDefaultFeatureProvider(featureType);

  }

  @Override

  public boolean useSubquery() {

    if (this.store == null) {

      return false;

    }

    return !StringUtils.isEmpty(this.store.getParameters().getSQL());

  }

  @Override

  public SRSSolver getSRSSolver() {

    return this.srssolver;

  }

  @Override

  public JDBCStoreProvider createProvider(

          JDBCStoreParameters parameters,

          DataStoreProviderServices providerServices

  ) throws InitializeException {

    JDBCStoreProviderBase theStore = new JDBCStoreProviderBase(

            parameters,

            providerServices,

            DBHelper.newMetadataContainer(JDBCLibrary.NAME),

            this

    );

    this.initialize(theStore, parameters, theStore);

    return theStore;

  }

  @Override

  public JDBCServerExplorer createServerExplorer(

          JDBCServerExplorerParameters parameters,

          DataServerExplorerProviderServices providerServices

  ) throws InitializeException {

    JDBCServerExplorer explorer = new JDBCServerExplorerBase(

            parameters,

            providerServices,

            this

    );

    this.initialize(explorer, parameters, null);

    return explorer;

  }

  @Override

  public JDBCNewStoreParameters createNewStoreParameters() {

    return new JDBCNewStoreParameters();

  }

  @Override

  public JDBCStoreParameters createOpenStoreParameters() {

    return new JDBCStoreParameters();

  }

  @Override

  public JDBCStoreParameters createOpenStoreParameters(JDBCServerExplorerParameters parameters) {

    JDBCStoreParameters params = this.createOpenStoreParameters();

    params.setHost(parameters.getHost());

    params.setPort(parameters.getPort());

    params.setDBName(parameters.getDBName());

    params.setUser(parameters.getUser());

    params.setPassword(parameters.getPassword());

    params.setCatalog(parameters.getCatalog());

    params.setSchema(parameters.getSchema());

    params.setJDBCDriverClassName(parameters.getJDBCDriverClassName());

    params.setUrl(parameters.getUrl());

    if( parameters instanceof FilesystemStoreParameters ) {

        File f = ((FilesystemStoreParameters) parameters).getFile();

        ((FilesystemStoreParameters) params).setFile(f);

    }

    return params;

  }

  @Override

  public JDBCServerExplorerParameters createServerExplorerParameters() {

    return new JDBCServerExplorerParameters();

  }

  @Override

  public String getSourceId(JDBCStoreParameters parameters) {

    return parameters.getHost() + ":"

            + parameters.getDBName() + ":"

            + parameters.getSchema() + ":"

            + parameters.tableID();

  }

  @Override

  public boolean isThreadSafe() {

    return true;

  }

  /** 

   * This method has been overriden in Oracle provider

   * 

   * @param sqlbuilder

   * @param type

   * @param extra_column_names 

   */

  @Override

  public void processSpecialFunctions(

          SQLBuilder sqlbuilder,

          FeatureType type,

          List<String> extra_column_names) {

    replaceForeingValueFunction(sqlbuilder, type, extra_column_names);

    replaceExistsFunction(sqlbuilder, type, extra_column_names);

  }

  private void replaceExistsFunction(

          SQLBuilder sqlbuilder,

          FeatureType type,

          final List<String> extra_column_names) {

    //  Si lse encuentra una construccion del tipo:

    //    SELECT ... FROM ... WHERE ... EXISTS(list, 'EXISTS_ID') ...

    //  se traslada a:

    //    SELECT ... EXISTS(list) AS EXISTS_ID FROM ... WHERE ... EXISTS(list) ...

    //  Y se a?ade el valor ESISTS_ID a las columnas extra a recuperar de la consulta.

    //          

    final SQLBuilder.SelectBuilder select = sqlbuilder.select();

    final ExpressionBuilder where = select.where();

    if (where == null || where.isEmpty() || select.has_group_by() ) {

      return;

    }

    final List<ExpressionBuilder.Value[]> value_replacements = new ArrayList<>();

    where.accept(new ExpressionBuilder.Visitor() {

      @Override

      public void visit(ExpressionBuilder.Visitable value) {

        if (!(value instanceof ExpressionBuilder.Function)) {

          return;

        }

        ExpressionBuilder.Function function = (ExpressionBuilder.Function) value;

        if (!StringUtils.equalsIgnoreCase(function.name(), FUNCTION_EXISTS)) {

          return;

        }

        if (function.parameters().size() != 2) {

          return;

        }

        ExpressionBuilder.Value arg0 = function.parameters().get(0);

        ExpressionBuilder.Value arg1 = function.parameters().get(1);

        if (arg1 == null) {

          return;

        }

        String columnName = (String) ((ExpressionBuilder.Constant) arg1).value();

        SQLBuilder.SelectColumnBuilder column = select.column();

        column.value(

                sqlbuilder.expression().function(FUNCTION_EXISTS, arg0)

        );

        column.as(columnName);

        if( extra_column_names!=null ) {

          extra_column_names.add(columnName);

        }

      }

    }, null);

    if (value_replacements.isEmpty()) {

      return;

    }

    // Realizamos los reemplazos calculados previamente (value_replacements).

    for (ExpressionBuilder.Value[] replaceValue : value_replacements) {

      ExpressionBuilder.Value target = replaceValue[0];

      ExpressionBuilder.Value replacement = replaceValue[1];

      sqlbuilder.select().replace(target, replacement);

    }

  }

  protected void replaceForeingValueFunction(

          SQLBuilder sqlbuilder,

          FeatureType type,

          List<String> extra_column_names) {

    try {

      // See test SQLBuilderTest->testForeingValue()

      final ExpressionBuilder where = sqlbuilder.select().where();

//      if (where == null || where.isEmpty()) {

//        return;

//      }

      final SQLBuilder.TableNameBuilder table = sqlbuilder.select().from().table();

      final ExpressionBuilder expbuilder = sqlbuilder.expression();

      final List<String> foreing_value_args;

      if (extra_column_names == null || sqlbuilder.select().has_group_by()) {

        foreing_value_args = new ArrayList<>();

      } else {

        foreing_value_args = extra_column_names;

      }

      final List<ExpressionBuilder.Value[]> value_replacements = new ArrayList<>();

      // Buscamos las llamadas a la funcion "foreing_value" y nos quedamos

      // el argumento de esta asi como por que tendriamos que sustituirla 

      // una vez hechos los left joins que toquen.

      sqlbuilder.select().accept(new ExpressionBuilder.Visitor() {

        @Override

        public void visit(ExpressionBuilder.Visitable value) {

          // Requiere que sea la funcion "FOREING_VALUE con un solo 

          // argumento que sea una constante de tipo string.

          if (!(value instanceof ExpressionBuilder.Function)) {

            return;

          }

          ExpressionBuilder.Function function = (ExpressionBuilder.Function) value;

          if (!StringUtils.equalsIgnoreCase(function.name(), FUNCTION_FOREING_VALUE)) {

            return;

          }

          if (function.parameters().size() != 1) {

            return;

          }

          ExpressionBuilder.Value arg = function.parameters().get(0);

          if (!(arg instanceof ExpressionBuilder.Constant)) {

            return;

          }

          Object arg_value = ((ExpressionBuilder.Constant) arg).value();

          if (!(arg_value instanceof CharSequence)) {

            return;

          }

          String foreing_value_arg = arg_value.toString();

          String[] foreingNameParts = StringUtils.split(foreing_value_arg, "[.]");

          if (foreingNameParts.length != 2) {

            // De momento solo tratamos joins entre dos tablas.

            return;

          }

          String columnNameLocal = foreingNameParts[0];

          String columnNameForeing = foreingNameParts[1];

          FeatureAttributeDescriptor attr = type.getAttributeDescriptor(columnNameLocal);

          if (attr==null) {

              throw new RuntimeException("Cannot find in feature type attribute:"+columnNameLocal);

          }

          if (!attr.isForeingKey()) {

            // Uhm... si el argumento no referencia a un campo que es

            // clave ajena no lo procesamos. 

            // ? Deberiamos lanzar un error ?

            return;

          }

          // Nos guardaremos por que hay que reemplazar la funcion 

          // FOREING_VALUE, y su argumento para mas tarde.

          ForeingKey foreingKey = attr.getForeingKey();

          SQLBuilder.TableNameBuilder foreingTable = sqlbuilder.createTableNameBuilder()

                  .database(table.getDatabase())

                  .schema(table.getSchema())

                  .name(foreingKey.getTableName());

          // Reemplzaremos la funcion FOREING_VALUE, por el acceso al campo

          // que toca de la tabla a la que referencia la clave ajena.

          ExpressionBuilder.Variable function_replacement = sqlbuilder.column(foreingTable, columnNameForeing);

          value_replacements.add(

                  new ExpressionBuilder.Value[]{

                    function,

                    function_replacement

                  }

          );

          if (!foreing_value_args.contains(foreing_value_arg)) {

            foreing_value_args.add(foreing_value_arg);

          }

        }

      }, null);

      // Si no habia ningun llamada a la funcion FOREING_VALUE, no hay que

      // hacer nada.

      if (foreing_value_args.isEmpty()) {

        return;

      }

      // Calculamos que referencias de columnas hemos de cambiar para 

      // que no aparezcan ambiguedades al hacer el join (nombres de

      // columna de una y otra tabla que coincidan).

      // Para las columnas que puedan dar conflicto se prepara un reemplazo 

      // de estas que tenga el nombre de tabla.

      for (ExpressionBuilder.Variable variable : sqlbuilder.variables()) {

        if (variable instanceof SQLBuilderBase.ColumnBase) {

          continue;

        }

        for (String foreingName : foreing_value_args) {

          String[] foreingNameParts = foreingName.split("[.]");

          if (foreingNameParts.length != 2) {

            continue;

          }

          String columnNameLocal = foreingNameParts[0];

          String columnNameForeing = foreingNameParts[1];

          if (StringUtils.equalsIgnoreCase(variable.name(), columnNameForeing)

                  || StringUtils.equalsIgnoreCase(variable.name(), columnNameLocal)) {

            ExpressionBuilder.Variable variable_replacement = sqlbuilder.column(

                    table,

                    variable.name()

            );

            value_replacements.add(

                    new ExpressionBuilder.Value[]{

                      variable,

                      variable_replacement

                    }

            );

          }

        }

      }

      // Realizamos los reemplazos calculados previamente (value_replacements).

      for (ExpressionBuilder.Value[] replaceValue : value_replacements) {

        ExpressionBuilder.Value target = replaceValue[0];

        ExpressionBuilder.Value replacement = replaceValue[1];

        sqlbuilder.select().replace(target, replacement);

      }

        // A?adimos a la SQL los "LEFT JOIN" que toca para poder acceder

        // a los valores referenciados por la funcion FOREING_VALUE.

        // Ademas a?adimos los valores referenciados por la funcion FOREING_VALUE

        // como columnas de la SQL para poder acceder a ellos si fuese necesario.

        HashSet usedLeftJoins = new HashSet();

      for (String foreingName : foreing_value_args) {

        String[] foreingNameParts = foreingName.split("[.]");

        if (foreingNameParts.length != 2) {

          continue;

        }

        String columnNameLocal = foreingNameParts[0];

        String columnNameForeing = foreingNameParts[1];

        FeatureAttributeDescriptor attr = type.getAttributeDescriptor(columnNameLocal);

        if (attr.isForeingKey()) {

          ForeingKey foreingKey = attr.getForeingKey();

          SQLBuilder.TableNameBuilder foreingTable = sqlbuilder.createTableNameBuilder()

                  .database(table.getDatabase())

                  .schema(table.getSchema())

                  .name(foreingKey.getTableName());

          SQLBuilder.TableNameBuilder mainTable = sqlbuilder.createTableNameBuilder()

                  .database(table.getDatabase())

                  .schema(table.getSchema())

                  .name(table.getName());

          if (!usedLeftJoins.contains(foreingTable.getName())) {

            sqlbuilder.select().from()

                    .left_join(

                            foreingTable,

                            expbuilder.eq(

                                    sqlbuilder.column(mainTable, columnNameLocal),

                                    sqlbuilder.column(foreingTable, foreingKey.getCodeName())

                            )

                    );

            usedLeftJoins.add(foreingTable.getName());

          }

          if (!sqlbuilder.select().has_group_by()) {

                sqlbuilder.select().column().name(foreingTable, columnNameForeing);

          }

        }

      }

        for (SQLBuilder.SelectColumnBuilder column : sqlbuilder.select().getColumns()) {

            if(column.getTable()==null && column.getName()!=null) {

                column.name(table, column.getName());

            }

        }

    } catch (Throwable th) {

      LOGGER.warn("Can't replace FOREING_VALUE function.", th);

      throw th;

    } finally {

      LOGGER.trace("Exit from replaceForeingValueFunction.");

    }

  }

    @Override

    public void setTransaction(DataTransactionServices transaction) {

        this.transaction = transaction;

    }

    @Override

    public String toString() {

        try {

            return String.format("%s %x %s", this.getClass().getSimpleName(), this.hashCode(), this.connectionParameters.getUrl());

        } catch (Exception e) {

            return super.toString();

        }

    }

}