1 /* 2 * Copyright (C) 2015 The Dagger 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 17 package dagger.multibindings; 18 19 import static java.lang.annotation.ElementType.METHOD; 20 import static java.lang.annotation.RetentionPolicy.RUNTIME; 21 22 import java.lang.annotation.Documented; 23 import java.lang.annotation.Retention; 24 import java.lang.annotation.Target; 25 26 /** 27 * Annotates abstract module methods that declare multibindings. 28 * 29 * <p>You can declare that a multibound set or map is bound by annotating an abstract module method 30 * that returns the set or map you want to declare with {@code @Multibinds}. 31 * 32 * <p>You do not have to use {@code @Multibinds} for sets or maps that have at least one 33 * contribution, but you do have to declare them if they may be empty. 34 * 35 * <pre><code> 36 * {@literal @Module} abstract class MyModule { 37 * {@literal @Multibinds abstract Set<Foo> aSet();} 38 * {@literal @Multibinds abstract @MyQualifier Set<Foo> aQualifiedSet();} 39 * {@literal @Multibinds abstract Map<String, Foo> aMap();} 40 * {@literal @Multibinds abstract @MyQualifier Map<String, Foo> aQualifiedMap();} 41 * 42 * {@literal @Provides} 43 * {@literal static Object usesMultibindings(Set<Foo> set, @MyQualifier Map<String, Foo> map}) { 44 * return … 45 * } 46 * }</code></pre> 47 * 48 * <p>A given set or map multibinding can be declared any number of times without error. Dagger 49 * never implements or calls any {@code @Multibinds} methods. 50 * 51 * @see <a href="https://dagger.dev/multibindings">Multibindings</a> 52 */ 53 @Documented 54 @Target(METHOD) 55 @Retention(RUNTIME) 56 public @interface Multibinds {} 57