| /** |
| * Copyright (C) 2015 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.inject.multibindings; |
| |
| import static java.lang.annotation.ElementType.ANNOTATION_TYPE; |
| import static java.lang.annotation.RetentionPolicy.RUNTIME; |
| |
| import java.lang.annotation.Documented; |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.Target; |
| |
| /** |
| * Allows users define customized key type annotations for map bindings by annotating an annotation |
| * of a {@code Map}'s key type. The custom key annotation can be applied to methods also annotated |
| * with {@literal @}{@link ProvidesIntoMap}. |
| * |
| * <p>A {@link StringMapKey} and {@link ClassMapKey} are provided for convenience with maps whose |
| * keys are strings or classes. For maps with enums or primitive types as keys, you must provide |
| * your own MapKey annotation, such as this one for an enum: |
| * |
| * <pre> |
| * {@literal @}MapKey(unwrapValue = true) |
| * {@literal @}Retention(RUNTIME) |
| * public {@literal @}interface MyCustomEnumKey { |
| * MyCustomEnum value(); |
| * } |
| * </pre> |
| * |
| * You can also use the whole annotation as the key, if {@code unwrapValue=false}. |
| * When unwrapValue is false, the annotation type will be the key type for the injected map and |
| * the annotation instances will be the key values. If {@code unwrapValue=true}, the value() type |
| * will be the key type for injected map and the value() instances will be the keys values. |
| * |
| * @since 4.0 |
| */ |
| @Documented |
| @Target(ANNOTATION_TYPE) |
| @Retention(RUNTIME) |
| public @interface MapKey { |
| /** |
| * if {@code unwrapValue} is false, then the whole annotation will be the type and annotation |
| * instances will be the keys. If {@code unwrapValue} is true, the value() type of key type |
| * annotation will be the key type for injected map and the value instances will be the keys. |
| */ |
| boolean unwrapValue() default true; |
| } |