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.expressionevaluator.impl.function.dataaccess;

import java.util.List;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Code;

import org.gvsig.expressionevaluator.Codes;

import org.gvsig.expressionevaluator.ExpressionRuntimeException;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.Optimizer;

import org.gvsig.expressionevaluator.impl.DALFunctions;

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

import org.gvsig.expressionevaluator.ExpressionEvaluator;

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

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

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

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

import org.gvsig.fmap.dal.impl.expressionevaluator.DefaultFeatureExpressionEvaluator;

import org.gvsig.expressionevaluator.Code.Callable;

import org.gvsig.expressionevaluator.ExpressionBuilder;

import org.gvsig.expressionevaluator.ExpressionBuilder.Value;

import org.gvsig.fmap.dal.SQLBuilder;

import org.gvsig.fmap.dal.feature.impl.DefaultFeatureQueryOrder;

/**

 *

 * @author jjdelcerro

 */

@SuppressWarnings("UseSpecificCatch")

public class SelectFunction

        extends AbstractSelectFunction

        implements Optimizer.FunctionOptimizer {

    public SelectFunction() {

        super(DALFunctions.GROUP_DATA_ACCESS,

                FUNCTION_SELECT,

                Range.is(6),

                "Returns a list of features of the table by applying the filter, order and limit indicated.\n"

                + "The syntax is:\n\n"

                + "SELECT * FROM table WHERE boolean_expression ORDER BY order_column LIMIT limit;\n\n"

                + "Indicate a filter expression with WHERE, an order or LIMIT is optional.\n"

                + "You can use an asterisk or enter the column names you want to retrieve separated by commas.\n"

                + "The SELECT statement must always end with a semicolon.",

                "SELECT * FROM table WHERE boolean_expression ORDER BY order_column LIMIT limit;",

                new String[]{

                    "column_names/asterisk - Names of the columns table to retrieve.",

                    "table_name - Name of the table",

                    "filter - boolean expression to apply as filter",

                    "order_column - the order used to retrieve the features. It is a list of column names separated by a comma. The column name can optionally be followed by ASC or DESC to indicate whether the order should be ascending or descending.",

                    "limit - Maximum number of features to return"

                },

                "List",

                true

        );

    }

    @Override

    public boolean isHidden() {

        return false;

    }

    @Override

    public boolean allowConstantFolding() {

        return false;

    }

    @Override

    public boolean useArgumentsInsteadObjects() {

        return true;

    }

    @Override

    public Object call(Interpreter interpreter, Object[] args) throws Exception {

        throw new UnsupportedOperationException();

    }

    private static final int COLUMNS = 0;

    private static final int TABLE = 1;

    private static final int WHERE = 2;

    private static final int ORDER = 3;

    private static final int ORDER_MODE = 4;

    private static final int LIMIT = 5;

    @Override

    public Object call(Interpreter interpreter, Codes args) throws Exception {

        String storeName = this.getTableName(args, TABLE);

        Code columns = getTupleOrNull(args, COLUMNS);

        Code where = this.getWhereCode(args, WHERE);

        Number limit = (Number) getObject(interpreter, args, LIMIT);

        Callable order = getTupleOrNull(args, ORDER);

        Callable order_mode = getTupleOrNull(args, ORDER_MODE);

        FeatureQueryOrder queryOrder = null;

        if (order != null || order_mode != null) {

            for (int n = 0; n < order.parameters().size(); n++) {

                String member = (String) interpreter.run(order.parameters().get(n));

                Boolean mode = (Boolean) interpreter.run(order_mode.parameters().get(n));

                if (queryOrder == null) {

                    queryOrder = new DefaultFeatureQueryOrder();

                }

                queryOrder.add(member, mode);

            }

        }

        FeatureStore featureStore;

        try {

            featureStore = this.getFeatureStore(storeName);

            if (featureStore == null) {

                throw new ExpressionRuntimeException("Cant locate the feature store '" + storeName + "' in function '" + this.name() + "'.");

            }

            List<Feature> features;

            FeatureQuery query = featureStore.createFeatureQuery();

            if (where != null) {

                Code where2 = removeOuterTablesReferences(interpreter, where);

                ExpressionEvaluator filter = new DefaultFeatureExpressionEvaluator(where2.toString());

                filter.toSymbolTable().addSymbolTable(interpreter.getSymbolTable());

                query.addFilter(filter);

            }

            if (queryOrder != null) {

                query.getOrder().copyFrom(queryOrder);

            }

            if (limit != null) {

                query.setLimit(limit.longValue());

            }

            // FIXME: add columns to query.addAttributeName() 

            query.retrievesAllAttributes();

            features = featureStore.getFeatures(query);

            return features;

        } catch (ExpressionRuntimeException ex) {

            throw ex;

        } catch (Exception ex) {

            throw new ExpressionRuntimeException("Problems calling '" + this.name() + "' function", ex);

        }

    }

    @Override

    public Code optimize(Optimizer optimizer, Callable caller) {

        return caller; // Don't optimize SELECT

    }

    @Override

    public ExpressionBuilder.Value toValue(ExpressionBuilder builder, Codes args) {

        try {

            SQLBuilder sqlBuilder = (SQLBuilder) builder.getProperty("SQLBUILDER");

            if(sqlBuilder == null){

                return super.toValue(builder, args);

            }

            SQLBuilder.SelectBuilder select = sqlBuilder.createSelectBuilder();

            String storeName = this.getTableName(args, TABLE);

            Callable columns = getTupleOrNull(args, COLUMNS);

            Code where = this.getWhereCode(args, WHERE);

            Callable order = getTupleOrNull(args, ORDER);

            Callable order_mode = getTupleOrNull(args, ORDER_MODE);

            Code limit = args.get(LIMIT);

            if (storeName != null) {

                select.from().table().name(storeName);

            }

            if (columns != null) {

                for (Code column : columns.parameters()) {

                    if (column instanceof Code.Identifier) {

                        select.column().name(

                                select.from().table(),

                                ((Code.Identifier) column).name()

                        );

                    }

                }

            }

            if (where != null) {

                select.where().value(where.toValue(builder));

            }

            if (limit != null) {

                select.limit(((Number) ((Code.Constant) limit).value()).longValue());

            }

            if (order != null || order_mode != null) {

                for (int n = 0; n < order.parameters().size(); n++) {

                    Code member = order.parameters().get(n);

                    Code.Constant mode = (Code.Constant) order_mode.parameters().get(n);

                    select.order_by().value(member.toValue(builder)).ascending((boolean) mode.value());

                }

            }

            return select;

        } catch (Exception ex) {

            return super.toValue(builder, args);

        }

    }

}