Sub.java

/*
 * 	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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package com.meidusa.amoeba.parser.function;

import java.util.List;

import com.meidusa.amoeba.sqljep.function.Subtract;
import com.meidusa.amoeba.parser.expression.Expression;
import com.meidusa.amoeba.sqljep.ParseException;

/**
 * 
 * @author <a href=mailto:piratebase@sina.com>Struct chen</a>
 *
 */
public class Sub extends AbstractFunction{
	/**
	 * ��list[0]��list[1]���������
	 */
	@SuppressWarnings("unchecked")
	public Comparable evaluate(List<Expression> list,Object[] parameters) throws ParseException {
		Comparable param1 = list.get(0).evaluate(parameters);
		Comparable param2 = list.get(1).evaluate(parameters);
		return Subtract.sub(param1, param2);
	}
	/**
	 * ��"list[0] - list[1]"�����ַ���
	 */
	public void toString(List<Expression> list,StringBuilder builder) {
		builder.append(list.get(0));
		builder.append(" - ");
		builder.append(list.get(1));
	}
	/**
	 * ����"-"
	 */
	public String getName() {
		return "-";
	}

}