1 /** 2 * Copyright (C) 2010 Google Inc. 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 com.google.inject.multibindings; 18 19 import com.google.inject.Binding; 20 import com.google.inject.Key; 21 import com.google.inject.TypeLiteral; 22 import com.google.inject.spi.Element; 23 import com.google.inject.spi.Elements; 24 25 import java.util.List; 26 27 /** 28 * A binding for a Multibinder. 29 * 30 * @param <T> The fully qualified type of the set, including Set. For example: 31 * <code>MultibinderBinding<Set<Boolean>></code> 32 * 33 * @since 3.0 34 * @author sameb (at) google.com (Sam Berlin) 35 */ 36 public interface MultibinderBinding<T> { 37 38 /** Returns the key for the set. */ 39 Key<T> getSetKey(); 40 41 /** 42 * Returns the TypeLiteral that describes the type of elements in the set. 43 * <p> 44 * The elements will always match the type Set's generic type. For example, if getSetKey returns a 45 * key of <code>Set<String></code>, then this will always return a 46 * <code>TypeLiteral<String></code>. 47 */ 48 TypeLiteral<?> getElementTypeLiteral(); 49 50 /** 51 * Returns all bindings that make up the set. This is only supported on bindings returned from an 52 * injector. This will throw {@link UnsupportedOperationException} if it is called on an element 53 * retrieved from {@link Elements#getElements}. 54 * <p> 55 * The elements will always match the type Set's generic type. For example, if getSetKey returns a 56 * key of <code>Set<String></code>, then this will always return a list of type 57 * <code>List<Binding<String>></code>. 58 */ 59 List<Binding<?>> getElements(); 60 61 /** 62 * Returns true if the multibinder permits duplicates. This is only supported on bindings returned 63 * from an injector. This will throw {@link UnsupportedOperationException} if it is called on a 64 * MultibinderBinding retrieved from {@link Elements#getElements}. 65 */ 66 boolean permitsDuplicates(); 67 68 /** 69 * Returns true if this Multibinder uses the given Element. This will be true for bindings that 70 * derive the elements of the set and other bindings that Multibinder uses internally. This will 71 * work for MultibinderBindings retrieved from an injector and {@link Elements#getElements}. 72 * Usually this is only necessary if you are working with elements retrieved from modules (without 73 * an Injector), otherwise {@link #getElements} and {@link #permitsDuplicates} are better options. 74 * <p> 75 * If you need to introspect the details of the set, such as the values or if it permits 76 * duplicates, it is necessary to pass the elements through an Injector and use 77 * {@link #getElements()} and {@link #permitsDuplicates()}. 78 */ 79 boolean containsElement(Element element); 80 } 81
