BaseExpressionList.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.expression;

import java.util.ArrayList;
import java.util.List;

/**
 * 
 * @author <a href=mailto:piratebase@sina.com>Struct chen</a>
 *
 */
public abstract class BaseExpressionList extends Expression {

    protected List<Expression> eList = new ArrayList<Expression>();

    public BaseExpressionList(){
    }

    public BaseExpressionList(Expression expression){
        if (expression != null) {
            addExpression(expression);
        }
    }
    /**
     * �õ����ʽeList
     * @return
     */
    public List<Expression> getAllExpression() {
        return eList;
    }

    /**
     * ���ʽ�Ƿ���Ҫʵʱ����
     */
    public boolean isRealtime() {
        for (Expression e : eList) {
            if (e.isRealtime()) {
                return true;//ֻҪeList�е�����һ�����ʽʵʱ���㣬�ñ��ʽ��ʵʱ����
            }
        }
        return false;
    }

    protected abstract BaseExpressionList getReverseObject();

    /**
     * ��eList�е�ÿһ��Ԫ��ȡ�������Ұ���ԭ����˳��ŵ�һ���µ�list��
     */
    @Override
    public Expression reverse() {
        BaseExpressionList list = getReverseObject();
        for (Expression e : this.eList) {
            Expression reversedExpression = e.reverse();
            list.addExpression(reversedExpression);
        }
        return list;
    }
    /**
     * �ѱ��ʽexpression��ӵ�eList��
     * @param expression
     */
    public void addExpression(Expression expression) {
        eList.add(expression);
    }
    /**
     * �õ�eList�Ĵ�С��size��
     * @return
     */
    public int getSize() {
        if (eList == null){
            return 0;
        }
        return eList.size();
    }

    /***
     *  ��eList�е�����Ԫ��append��builder�У������⴮�ַ���ǰ�����"("��")"
     * @param builder
     * @param concatString
     */
    protected void toString(StringBuilder builder, String concatString) {
        int current = 0;
        if (eList.size() >= 2) {
            builder.append("(");
        }
        for (Expression e : eList) {
            e.toString(builder);//????
            current++;
            if (current != eList.size()) {
                builder.append(concatString);
            }
        }
        if (eList.size() >= 2) {
            builder.append(")");
        }
//        System.out.println(builder);
    }
}