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.expressionbuilder.formatters;

import org.gvsig.expressionevaluator.Expression;

import org.gvsig.expressionevaluator.ExpressionBuilder;

import org.gvsig.expressionevaluator.ExpressionBuilder.Value;

import org.gvsig.expressionevaluator.Formatter;

import org.gvsig.fmap.dal.SQLBuilder;

import org.gvsig.fmap.dal.expressionevaluator.FeatureAttributeEmulatorExpression;

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

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

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

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

import org.gvsig.fmap.dal.store.jdbc2.spi.JDBCSQLBuilderBase;

import static org.gvsig.fmap.dal.store.jdbc2.spi.JDBCSQLBuilderBase.PROP_FEATURE_TYPE;

import static org.gvsig.fmap.dal.store.jdbc2.spi.JDBCSQLBuilderBase.PROP_JDBCHELPER;

/**

 *

 * @author jjdelcerro

 */

public class ComputedAttribute implements Formatter<Value> {

    private final SQLBuilder sqlbuilder;

    private final Formatter<Value> formatter;

    public ComputedAttribute(SQLBuilder sqlbuilder, Formatter<Value> formatter) {

        this.sqlbuilder = sqlbuilder;

        this.formatter = formatter;

    }

    @Override

    public boolean canApply(ExpressionBuilder.Value value) {

        if (value instanceof ExpressionBuilder.Variable) { 

            FeatureType featureType = (FeatureType) value.getProperty(PROP_FEATURE_TYPE);

            if( featureType==null ) {

                return false;

            }

            JDBCHelper jdbcHelper = (JDBCHelper) value.getProperty(PROP_JDBCHELPER);

            if( jdbcHelper==null ) {

                return false;

            }

            ExpressionBuilder.Variable variable = (ExpressionBuilder.Variable) value;

            FeatureAttributeDescriptor attr = featureType.getAttributeDescriptor(variable.name());

            if( attr==null || !attr.isComputed() ) {

                return false;

            }

            FeatureAttributeEmulator emulator = attr.getFeatureAttributeEmulator();

            if( !(emulator instanceof FeatureAttributeEmulatorExpression) ) {

                return false;

            }

            Expression expr = ((FeatureAttributeEmulatorExpression)emulator).getExpression();

            return jdbcHelper.supportExpression(featureType, expr.getPhrase());

        }

        return false;

    }

    @Override

    public String format(Value value) {

        FeatureType featureType = (FeatureType) value.getProperty(PROP_FEATURE_TYPE);

        ExpressionBuilder.Variable variable = (ExpressionBuilder.Variable) value;

        FeatureAttributeDescriptor attr = featureType.getAttributeDescriptor(variable.name());

        FeatureAttributeEmulator emulator = attr.getFeatureAttributeEmulator();

        Expression expr = ((FeatureAttributeEmulatorExpression)emulator).getExpression();

        return "("+ this.formatter.format(expr.getCode().toValue(this.sqlbuilder.expression()))+")";

    }

}