/**
* Alipay.com Inc.
* Copyright (c) 2004-2012 All Rights Reserved.
*/
package com.alipay.zdal.parser.sql.ast.expr;
import com.alipay.zdal.parser.sql.ast.SQLExprImpl;
import com.alipay.zdal.parser.sql.visitor.SQLASTVisitor;
/**
*
* @author xiaoqing.zhouxq
* @version $Id: SQLNullExpr.java, v 0.1 2012-11-17 ����3:18:38 xiaoqing.zhouxq Exp $
*/
public class SQLNullExpr extends SQLExprImpl implements SQLLiteralExpr {
private static final long serialVersionUID = 1L;
public SQLNullExpr() {
}
public void output(StringBuffer buf) {
buf.append("NULL");
}
protected void accept0(SQLASTVisitor visitor) {
visitor.visit(this);
visitor.endVisit(this);
}
public int hashCode() {
return 0;
}
public boolean equals(Object o) {
return o instanceof SQLNullExpr;
}
}