hunt.sql.builder.FunctionBuilder source code

1 /*
2  * Copyright 2015-2018 HuntLabs.cn.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 module hunt.sql.builder.FunctionBuilder;
17 
18 import hunt.sql.ast.SQLExpr;
19 import hunt.sql.ast.expr.SQLMethodInvokeExpr;
20 import hunt.sql.util.DBType;
21 
22 /**
23  * Created by wenshao on 09/07/2017.
24  */
25 public class FunctionBuilder {
26     private  string dbType;
27 
28     public this(string dbType) {
29         this.dbType = dbType;
30     }
31 
32     // for character function
33     public SQLMethodInvokeExpr length(SQLExpr expr) {
34         return new SQLMethodInvokeExpr("length", null, expr);
35     }
36 
37     public SQLMethodInvokeExpr lower(SQLExpr expr) {
38         return new SQLMethodInvokeExpr("lower", null, expr);
39     }
40 
41     public SQLMethodInvokeExpr upper(SQLExpr expr) {
42         return new SQLMethodInvokeExpr("upper", null, expr);
43     }
44 
45     public SQLMethodInvokeExpr substr(SQLExpr expr) {
46         return new SQLMethodInvokeExpr("substr", null, expr);
47     }
48 
49     public SQLMethodInvokeExpr ltrim(SQLExpr expr) {
50         return new SQLMethodInvokeExpr("ltrim", null, expr);
51     }
52 
53     public SQLMethodInvokeExpr rtrim(SQLExpr expr) {
54         return new SQLMethodInvokeExpr("rtrim", null, expr);
55     }
56 
57     public SQLMethodInvokeExpr trim(SQLExpr expr) {
58         return new SQLMethodInvokeExpr("trim", null, expr);
59     }
60 
61     public SQLMethodInvokeExpr ifnull(SQLExpr expr1, SQLExpr expr2) {
62         if (DBType.ALIYUN_ADS.name == dbType
63                 || DBType.PRESTO.name == dbType
64                 || DBType.ODPS.name == dbType) {
65             return new SQLMethodInvokeExpr("coalesce", null, expr1, expr2);
66         }
67 
68         if (DBType.ORACLE.name == dbType) {
69             return new SQLMethodInvokeExpr("nvl", null, expr1, expr2);
70         }
71 
72         if (DBType.SQL_SERVER.name == dbType) {
73             return new SQLMethodInvokeExpr("isnull", null, expr1, expr2);
74         }
75 
76         return new SQLMethodInvokeExpr("ifnull", null, expr1, expr2);
77     }
78 }