1 /**
2 * Copyright 2009-2019 the original author or authors.
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 package org.apache.ibatis.annotations;
17
18 import java.lang.annotation.Documented;
19 import java.lang.annotation.ElementType;
20 import java.lang.annotation.Retention;
21 import java.lang.annotation.RetentionPolicy;
22 import java.lang.annotation.Target;
23
24 /**
25 * The annotation that specify a method that provide an SQL for retrieving record(s).
26 *
27 * <p><br>
28 * <b>How to use:</b>
29 * <pre>
30 * public interface UserMapper {
31 *
32 * @SelectProvider(type = SqlProvider.class, method = "selectById")
33 * User selectById(int id);
34 *
35 * public static class SqlProvider {
36 * public static String selectById() {
37 * return "SELECT id, name FROM users WHERE id = #{id}";
38 * }
39 * }
40 *
41 * }
42 * </pre>
43 * @author Clinton Begin
44 */
45 @Documented
46 @Retention(RetentionPolicy.RUNTIME)
47 @Target(ElementType.METHOD)
48 public @interface SelectProvider {
49
50 /**
51 * Specify a type that implements an SQL provider method.
52 *
53 * @return a type that implements an SQL provider method
54 * @since 3.5.2
55 * @see #type()
56 */
57 Class<?> value() default void.class;
58
59 /**
60 * Specify a type that implements an SQL provider method.
61 * <p>
62 * This attribute is alias of {@link #value()}.
63 * </p>
64 *
65 * @return a type that implements an SQL provider method
66 * @see #value()
67 */
68 Class<?> type() default void.class;
69
70 /**
71 * Specify a method for providing an SQL.
72 *
73 * <p>
74 * Since 3.5.1, this attribute can omit.
75 * If this attribute omit, the MyBatis will call a method that decide by following rules.
76 * <ul>
77 * <li>
78 * If class that specified the {@link #type()} attribute implements the {@link org.apache.ibatis.builder.annotation.ProviderMethodResolver},
79 * the MyBatis use a method that returned by it
80 * </li>
81 * <li>
82 * If cannot resolve a method by {@link org.apache.ibatis.builder.annotation.ProviderMethodResolver}(= not implement it or it was returned {@code null}),
83 * the MyBatis will search and use a fallback method that named {@code provideSql} from specified type
84 * </li>
85 * </ul>
86 *
87 * @return a method name of method for providing an SQL
88 */
89 String method() default "";
90
91 }