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

import java.util.ArrayList;

import java.util.Hashtable;

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

/**

 * Implements the functionality of a null constant

 * 

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

 *

 */

public class NullConstant implements Expression{

        public void addArgument(int i, Expression arg) {

                throw new RuntimeException("Cannot add an argument to a constant");

        }

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

                return;

        }

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

                return null;

        }

        public ArrayList<Expression> getArguments() {

                return null;

        }

        public String getPattern() {

                return null;

        }

        public void setArguments(ArrayList<Expression> arguments) {

                // TODO Auto-generated method stub

                throw new Error("Not yet implemented");

        }

}