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Java example source code file (MapKey.java)
The MapKey.java Java example source code/** * 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; } Other Java examples (source code examples)Here is a short list of links related to this Java MapKey.java source code file: |
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