1*f585d8a3SJacky Wang /* 2*f585d8a3SJacky Wang * Copyright (C) 2007 The Dagger Authors. 3*f585d8a3SJacky Wang * 4*f585d8a3SJacky Wang * Licensed under the Apache License, Version 2.0 (the "License"); 5*f585d8a3SJacky Wang * you may not use this file except in compliance with the License. 6*f585d8a3SJacky Wang * You may obtain a copy of the License at 7*f585d8a3SJacky Wang * 8*f585d8a3SJacky Wang * http://www.apache.org/licenses/LICENSE-2.0 9*f585d8a3SJacky Wang * 10*f585d8a3SJacky Wang * Unless required by applicable law or agreed to in writing, software 11*f585d8a3SJacky Wang * distributed under the License is distributed on an "AS IS" BASIS, 12*f585d8a3SJacky Wang * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13*f585d8a3SJacky Wang * See the License for the specific language governing permissions and 14*f585d8a3SJacky Wang * limitations under the License. 15*f585d8a3SJacky Wang */ 16*f585d8a3SJacky Wang 17*f585d8a3SJacky Wang package dagger; 18*f585d8a3SJacky Wang 19*f585d8a3SJacky Wang import static java.lang.annotation.ElementType.METHOD; 20*f585d8a3SJacky Wang import static java.lang.annotation.RetentionPolicy.RUNTIME; 21*f585d8a3SJacky Wang 22*f585d8a3SJacky Wang import java.lang.annotation.Documented; 23*f585d8a3SJacky Wang import java.lang.annotation.Retention; 24*f585d8a3SJacky Wang import java.lang.annotation.Target; 25*f585d8a3SJacky Wang 26*f585d8a3SJacky Wang /** 27*f585d8a3SJacky Wang * Annotates methods of a {@linkplain Module module} to create a provider method binding. The 28*f585d8a3SJacky Wang * method's return type is bound to its returned value. The {@linkplain Component component} 29*f585d8a3SJacky Wang * implementation will pass dependencies to the method as parameters. 30*f585d8a3SJacky Wang * 31*f585d8a3SJacky Wang * <h3>Nullability</h3> 32*f585d8a3SJacky Wang * 33*f585d8a3SJacky Wang * <p>Dagger forbids injecting {@code null} by default. Component implementations that invoke 34*f585d8a3SJacky Wang * {@code @Provides} methods that return {@code null} will throw a {@link NullPointerException} 35*f585d8a3SJacky Wang * immediately thereafter. {@code @Provides} methods may opt into allowing {@code null} by 36*f585d8a3SJacky Wang * annotating the method with any {@code @Nullable} annotation like {@code 37*f585d8a3SJacky Wang * javax.annotation.Nullable} or {@code androidx.annotation.Nullable}. 38*f585d8a3SJacky Wang * 39*f585d8a3SJacky Wang * <p>If a {@code @Provides} method is marked {@code @Nullable}, Dagger will <em>only</em> allow 40*f585d8a3SJacky Wang * injection into sites that are marked {@code @Nullable} as well. A component that attempts to pair 41*f585d8a3SJacky Wang * a {@code @Nullable} provision with a non-{@code @Nullable} injection site will fail to compile. 42*f585d8a3SJacky Wang */ 43*f585d8a3SJacky Wang @Documented 44*f585d8a3SJacky Wang @Target(METHOD) 45*f585d8a3SJacky Wang @Retention(RUNTIME) 46*f585d8a3SJacky Wang public @interface Provides {} 47