| 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.cit.gvsig.fmap.Messages;

/**

 * Implements the funcionality of the negation operator which only can

 * be used in boolean expressions

 *

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

 *

 */

public class NotOperator extends Operator {

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

        public String getName() {

                return OperationTags.NOT_OP;

        }

        public NotOperator(Hashtable<String, Value> symbol_table) {

                super(symbol_table);

        }

        public Object evaluate()throws ExpressionException {

                if(arguments.size() > 1)

                        throw new ExpressionException(ExpressionException.INCORRECT_NUMBER_OF_ARGUMENTS);

                Object eval=((Expression)arguments.get(0)).evaluate();

                if (eval==null)

                        return false;

                boolean result = ((Boolean)eval).booleanValue();

                if (result)

                        return false;

                else

                        return true;

        }

        public Class getResultType()

        {

                return Boolean.class;

        }

        public void addArgument(int i, Expression arg) {

                arguments.add(i, arg);

        }

        public String getPattern() {

                return OperationTags.NOT_OP +"("+

                        Messages.getString(OperationTags.OPERAND)+")\n"+

                        Messages.getString(OperationTags.OPERAND)+" = "+

                        Messages.getString(OperationTags.BOOLEAN_VALUE);

        }

        public ArrayList<Expression> getArguments() {

                return arguments;

        }

        public void setArguments(ArrayList<Expression> arguments) {

                this.arguments = arguments;

        }

        public void check() throws ExpressionException {

                if (arguments.size() != 1)

                        throw new ExpressionException(ExpressionException.INCORRECT_NUMBER_OF_ARGUMENTS);

                if(! (arguments.get(0).evaluate() instanceof Boolean))

                        throw new ExpressionException(ExpressionException.CLASS_CASTING_EXCEPTION);

        }

}