| gvSIG desktop 1

/* gvSIG. Sistema de Informaci�n Geogr�fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * 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 2

 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 *

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib��ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 *

 *    or

 *

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 *

 *   +34 963163400

 *   dac@iver.es

 */

package org.gvsig.symbology.fmap.rendering.filter.operations;

import java.util.ArrayList;

import java.util.Hashtable;

import com.hardcode.gdbms.engine.values.Value;

import com.iver.andami.PluginServices;

/**

 * Implements the funcionality of the minus operator

 * 

 * @author Pepe Vidal Salvador - jose.vidal.salvador@iver.es

 *

 */

public class MinusOperator implements Expression {

        ArrayList<Expression> arguments = new ArrayList<Expression>();

        public Object evaluate(Hashtable<String, Value> symbol_table)throws ExpressionException {

                if(arguments.size() >= 2)

                {

                         Double result = (Double)((Expression)arguments.get(0)).evaluate(symbol_table);

                        for (int i = 1; i < arguments.size(); i++)

                        {

                            Expression function = (Expression)arguments.get(i);

                            result -= ((Double)function.evaluate(symbol_table));

                        }

                        return result;

                }

                else return -1*((Double)((Expression)arguments.get(0)).evaluate(symbol_table));                

        }

        public void addArgument(int i, Expression arg) {

                arguments.add(i, arg);        

        }

        public String getPattern() {

                return "("+PluginServices.getText(this,"operand")

                +" - "+PluginServices.getText(this, "operand")+ ")\n"+ 

                PluginServices.getText(this,"operand") +" = "+

                PluginServices.getText(this,"numeric_value" );                

                }

        public ArrayList<Expression> getArguments() {

                return arguments;

        }

        public void setArguments(ArrayList<Expression> arguments) {

                this.arguments = arguments;

        }

        public void check(Hashtable<String, Value> symbol_table) throws ExpressionException {

                for (int i = 0; i < arguments.size(); i++) {

                        if(!(arguments.get(i).evaluate(symbol_table)instanceof Double))

                                throw new ExpressionException(ExpressionException.CLASS_CASTING_EXCEPTION);        

                }

        }

}