/*
* JEF - Copyright 2009-2010 Jiyi (mr.jiyi@gmail.com)
*
* 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 jef.database.annotation;
/**
* SQL的四种Join类型<p>
* <tt>
* 因为JPA的javax.persistence.criteria.JoinType类型中没有全外连接，所以自行定义了一个JoinType
* </tt>
* <ul>
* <li>{@link #INNER}</li>
* <li>{@link #LEFT}</li>
* <li>{@link #RIGHT}</li>
* <li>{@link #FULL}</li>
* </ul>
*
* <s>啥，还要笛卡尔积连接……</s>
* @author Jiyi
* @Date 2011-4-12
*/
public enum JoinType {
/**
* 内连接
*/
INNER,
/**
* 左外连接
*/
LEFT,
/**
* 右外连接
*/
RIGHT,
/**
* 全外连接
*/
FULL;
private String lowerName;
private JoinType(){
lowerName=this.name().toLowerCase();
}
/**
* 返回翻转后的连接方式
* @param source
* @return
*/
public static JoinType flip(JoinType source){
switch(source){
case LEFT:
return RIGHT;
case RIGHT:
return LEFT;
default:
return source;
}
}
/**
* 返回小写的名称
* @return
*/
public String nameLower() {
return lowerName;
}
}