1 /*
2  * Copyright (C) 2013 The Android Open Source Project
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 android.annotation;
17 
18 import java.lang.annotation.Retention;
19 import java.lang.annotation.Target;
20 
21 import static java.lang.annotation.ElementType.FIELD;
22 import static java.lang.annotation.ElementType.METHOD;
23 import static java.lang.annotation.ElementType.PARAMETER;
24 import static java.lang.annotation.RetentionPolicy.SOURCE;
25 
26 /**
27  * Denotes that a parameter, field or method return value can be null.
28  * <p>
29  * When decorating a method call parameter, this denotes that the parameter can
30  * legitimately be null and the method will gracefully deal with it. Typically
31  * used on optional parameters.
32  * <p>
33  * When decorating a method, this denotes the method might legitimately return
34  * null.
35  * <p>
36  * This is a marker annotation and it has no specific attributes.
37  *
38  * @hide
39  */
40 @Retention(SOURCE)
41 @Target({METHOD, PARAMETER, FIELD})
42 public @interface Nullable {
43 }
44