/*
* This program is free software; you can redistribute it and/or modify it under the terms of
* the GNU AFFERO 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 AFFERO GENERAL PUBLIC LICENSE for more details.
* You should have received a copy of the GNU AFFERO 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.expression;
/**
* ���ʽ����
*
* @author <a href=mailto:piratebase@sina.com>Struct chen</a>
*
*/
public abstract class Expression {
public Expression(){
}
public boolean canEvaluate() {
return true;
}
/**
* ���ʽȡ��
*/
public abstract Expression reverse();
protected abstract void toString(StringBuilder builder);
/**
* ��ʾ�ñ��ʽ�Ƿ���Ҫʵʱ����
*/
public abstract boolean isRealtime();
/**
* ���ʽ����
*/
@SuppressWarnings("unchecked")
public abstract Comparable evaluate(Object[] parameters);
public String toString() {
StringBuilder builder = new StringBuilder();
this.toString(builder);
return builder.toString();
}
}