/**
 * Alipay.com Inc.
 * Copyright (c) 2004-2012 All Rights Reserved.
 */
package com.alipay.zdal.parser.sql.ast;

import java.io.Serializable;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.alipay.zdal.parser.sql.visitor.SQLASTVisitor;

/**
 * 
 * @author xiaoqing.zhouxq
 * @version $Id: SQLObjectImpl.java, v 0.1 2012-11-17 ����3:13:23 xiaoqing.zhouxq Exp $
 */
public abstract class SQLObjectImpl implements SQLObject, Serializable {

    private static final long   serialVersionUID = 5569722716326763762L;

    private SQLObject           parent;

    private Map<String, Object> attributes;

    public SQLObjectImpl() {
    }

    public final void accept(SQLASTVisitor visitor) {
        if (visitor == null) {
            throw new IllegalArgumentException();
        }

        visitor.preVisit(this);

        accept0(visitor);

        visitor.postVisit(this);
    }

    protected abstract void accept0(SQLASTVisitor visitor);

    protected final void acceptChild(SQLASTVisitor visitor, List<? extends SQLObject> children) {
        for (SQLObject child : children)
            acceptChild(visitor, child);
    }

    protected final void acceptChild(SQLASTVisitor visitor, SQLObject child) {
        if (child == null) {
            return;
        }

        child.accept(visitor);
    }

    public void output(StringBuffer buf) {
        buf.append(super.toString());
    }

    public String toString() {
        StringBuffer buf = new StringBuffer();
        output(buf);
        return buf.toString();
    }

    public SQLObject getParent() {
        return parent;
    }

    public void setParent(SQLObject parent) {
        this.parent = parent;
    }

    public Map<String, Object> getAttributes() {
        if (attributes == null) {
            attributes = new HashMap<String, Object>(1);
        }

        return attributes;
    }

    public Object getAttribute(String name) {
        if (attributes == null) {
            return null;
        }

        return attributes.get(name);
    }

    public void putAttribute(String name, Object value) {
        if (attributes == null) {
            attributes = new HashMap<String, Object>(1);
        }

        attributes.put(name, value);
    }

    public Map<String, Object> getAttributesDirect() {
        return attributes;
    }
}