1 package ca.uhn.fhir.model.api.annotation;
2
3 /*
4 * #%L
5 * HAPI FHIR - Core Library
6 * %%
7 * Copyright (C) 2014 University Health Network
8 * %%
9 * Licensed under the Apache License, Version 2.0 (the "License");
10 * you may not use this file except in compliance with the License.
11 * You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 * #L%
21 */
22
23 import java.lang.annotation.ElementType;
24 import java.lang.annotation.Retention;
25 import java.lang.annotation.RetentionPolicy;
26 import java.lang.annotation.Target;
27
28 import ca.uhn.fhir.model.api.IElement;
29
30 /**
31 * Field annotation for fields within resource and datatype definitions, indicating
32 * a child of that type.
33 */
34 @Retention(RetentionPolicy.RUNTIME)
35 @Target(value= {ElementType.FIELD})
36 public @interface Child {
37
38 /**
39 * Constant value to supply for {@link #order()} when the order is defined
40 * elsewhere
41 */
42 int ORDER_UNKNOWN = -1;
43
44 /**
45 * Constant value to supply for {@link #max()} to indicate '*' (no maximum)
46 */
47 int MAX_UNLIMITED = -1;
48
49 /**
50 * Constant value to supply for {@link #order()} to indicate that this child should replace the
51 * entry in the superclass with the same name (and take its {@link Child#order() order} value
52 * in the process). This is useful if you wish to redefine an existing field in a resource/type
53 * definition in order to constrain/extend it.
54 */
55 int REPLACE_PARENT = -2;
56
57 /**
58 * The name of this field, as it will appear in serialized versions of the message
59 */
60 String name();
61
62 /**
63 * The order in which this field comes within its parent. The first field should have a
64 * value of 0, the second a value of 1, etc.
65 */
66 int order() default ORDER_UNKNOWN;
67
68 /**
69 * The minimum number of repetitions allowed for this child
70 */
71 int min() default 0;
72
73 /**
74 * The maximum number of repetitions allowed for this child. Should be
75 * set to {@link #MAX_UNLIMITED} if there is no limit to the number of
76 * repetitions.
77 */
78 int max() default 1;
79
80 /**
81 * Lists the allowable types for this field, if the field supports multiple
82 * types (otherwise does not need to be populated).
83 * <p>
84 * For example, if this field supports either DateTimeDt or BooleanDt types,
85 * those two classes should be supplied here.
86 * </p>
87 */
88 Class<? extends IElement>[] type() default {};
89
90 // Not implemented
91 // /**
92 // * This value is used when extending a built-in model class and defining a
93 // * field to replace a field within the built-in class. For example, the {@link Patient}
94 // * resource has a {@link Patient#getName() name} field, but if you wanted to extend Patient and
95 // * provide your own implementation of {@link HumanNameDt} (most likely your own subclass of
96 // * HumanNameDt which adds extensions of your choosing) you could do that using a replacement field.
97 // */
98 // String replaces() default "";
99
100 }