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

import java.io.Serializable;

import com.alipay.zdal.parser.sql.ast.SQLExpr;
import com.alipay.zdal.parser.sql.ast.SQLExprImpl;
import com.alipay.zdal.parser.sql.visitor.SQLASTVisitor;

/**
 * 
 * @author xiaoqing.zhouxq
 * @version $Id: SQLNotExpr.java, v 0.1 2012-11-17 ����3:18:31 xiaoqing.zhouxq Exp $
 */
public class SQLNotExpr extends SQLExprImpl implements Serializable {

    private static final long serialVersionUID = 1L;
    public SQLExpr            expr;

    public SQLNotExpr() {

    }

    public SQLNotExpr(SQLExpr expr) {

        this.expr = expr;
    }

    public SQLExpr getExpr() {
        return this.expr;
    }

    public void setExpr(SQLExpr expr) {
        this.expr = expr;
    }

    @Override
    public void output(StringBuffer buf) {
        buf.append(" NOT ");
        this.expr.output(buf);
    }

    protected void accept0(SQLASTVisitor visitor) {
        if (visitor.visit(this)) {
            acceptChild(visitor, this.expr);
        }

        visitor.endVisit(this);
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((expr == null) ? 0 : expr.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        SQLNotExpr other = (SQLNotExpr) obj;
        if (expr == null) {
            if (other.expr != null) {
                return false;
            }
        } else if (!expr.equals(other.expr)) {
            return false;
        }
        return true;
    }
}