/*
 * Copyright 1999-2011 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.druid.sql.ast.statement;

import com.alibaba.druid.sql.ast.SQLExpr;
import com.alibaba.druid.sql.ast.SQLObjectImpl;
import com.alibaba.druid.sql.visitor.SQLASTVisitor;

public class SQLSelectItem extends SQLObjectImpl {

    private static final long serialVersionUID = 1L;

    private SQLExpr           expr;
    private String            alias;

    public SQLSelectItem(){

    }
    
    public SQLSelectItem(SQLExpr expr) {
        this(expr, null);
    }

    public SQLSelectItem(SQLExpr expr, String alias){

        this.expr = expr;
        this.alias = alias;
    }

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

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

    public String getAlias() {
        return this.alias;
    }

    public void setAlias(String alias) {
        this.alias = alias;
    }

    public void output(StringBuffer buf) {
        this.expr.output(buf);
        if ((this.alias != null) && (this.alias.length() != 0)) {
            buf.append(" AS ");
            buf.append(this.alias);
        }
    }

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