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 androidx.annotation; 17 18 import static java.lang.annotation.ElementType.ANNOTATION_TYPE; 19 import static java.lang.annotation.ElementType.FIELD; 20 import static java.lang.annotation.ElementType.LOCAL_VARIABLE; 21 import static java.lang.annotation.ElementType.METHOD; 22 import static java.lang.annotation.ElementType.PACKAGE; 23 import static java.lang.annotation.ElementType.PARAMETER; 24 import static java.lang.annotation.RetentionPolicy.CLASS; 25 26 import java.lang.annotation.Documented; 27 import java.lang.annotation.Retention; 28 import java.lang.annotation.Target; 29 30 /** 31 * Denotes that a parameter, field or method return value can be null. 32 * <p> 33 * When decorating a method call parameter, this denotes that the parameter can 34 * legitimately be null and the method will gracefully deal with it. Typically 35 * used on optional parameters. 36 * <p> 37 * When decorating a method, this denotes the method might legitimately return 38 * null. 39 * <p> 40 * This is a marker annotation and it has no specific attributes. 41 */ 42 @Documented 43 @Retention(CLASS) 44 @Target({METHOD, PARAMETER, FIELD, LOCAL_VARIABLE, ANNOTATION_TYPE, PACKAGE}) 45 public @interface Nullable { 46 } 47
