| 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;

/**

 * Interface that all the operators of an expression to be parsed

 * has to implement

 * 

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

 */

public interface Expression {

        /**

         * Returns true if the expression is correctly evaluated using the

         * HashTable for that

         * 

         * @param symbol_table

         * @return

         * @throws ExpressionException

         */

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

        /**

         * Returns an String containing the pattern for the operator. That is, the

         * type of its arguments and its solution 

         * 

         * @return String with the pattern

         */

        public String getPattern();

        /**

         * Adds an argument (which is an Expression) to the operator in the

         * ith position.

         * 

         * @param i position where the argument will be added

         * @param arg argument to be added

         */

        public void addArgument(int i, Expression arg);

        /**

         * Obtains the arguments of the Expression

         * 

         * @return ArrayList with the arguments

         */

        public ArrayList<Expression> getArguments() ;

        /**

         * Sets the arguments of the Expression

         *  

         * @param arguments

         */

        public void setArguments(ArrayList<Expression> arguments);

        /**

         * Checks if the semantic of the Expression is correct using for that

         * the values of the HashTable if it is necessary

         * 

         * @param symbol_table which contains the symbols

         * @throws ExpressionException

         */

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

}