1/** 2 * Copyright (C) 2008 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 17package com.google.inject.internal; 18 19import static com.google.common.base.Preconditions.checkNotNull; 20 21import com.google.inject.Binder; 22import com.google.inject.Key; 23import com.google.inject.Scope; 24import com.google.inject.spi.Element; 25import com.google.inject.spi.InstanceBinding; 26 27import java.lang.annotation.Annotation; 28import java.util.List; 29 30/** 31 * Bind a value or constant. 32 * 33 * @author jessewilson@google.com (Jesse Wilson) 34 */ 35public abstract class AbstractBindingBuilder<T> { 36 37 public static final String IMPLEMENTATION_ALREADY_SET = "Implementation is set more than once."; 38 public static final String SINGLE_INSTANCE_AND_SCOPE 39 = "Setting the scope is not permitted when binding to a single instance."; 40 public static final String SCOPE_ALREADY_SET = "Scope is set more than once."; 41 public static final String BINDING_TO_NULL = "Binding to null instances is not allowed. " 42 + "Use toProvider(Providers.of(null)) if this is your intended behaviour."; 43 public static final String CONSTANT_VALUE_ALREADY_SET = "Constant value is set more than once."; 44 public static final String ANNOTATION_ALREADY_SPECIFIED 45 = "More than one annotation is specified for this binding."; 46 47 protected static final Key<?> NULL_KEY = Key.get(Void.class); 48 49 protected List<Element> elements; 50 protected int position; 51 protected final Binder binder; 52 private BindingImpl<T> binding; 53 54 public AbstractBindingBuilder(Binder binder, List<Element> elements, Object source, Key<T> key) { 55 this.binder = binder; 56 this.elements = elements; 57 this.position = elements.size(); 58 this.binding = new UntargettedBindingImpl<T>(source, key, Scoping.UNSCOPED); 59 elements.add(position, this.binding); 60 } 61 62 protected BindingImpl<T> getBinding() { 63 return binding; 64 } 65 66 protected BindingImpl<T> setBinding(BindingImpl<T> binding) { 67 this.binding = binding; 68 elements.set(position, binding); 69 return binding; 70 } 71 72 /** Sets the binding to a copy with the specified annotation on the bound key */ 73 protected BindingImpl<T> annotatedWithInternal(Class<? extends Annotation> annotationType) { 74 checkNotNull(annotationType, "annotationType"); 75 checkNotAnnotated(); 76 return setBinding(binding.withKey( 77 Key.get(this.binding.getKey().getTypeLiteral(), annotationType))); 78 } 79 80 /** Sets the binding to a copy with the specified annotation on the bound key */ 81 protected BindingImpl<T> annotatedWithInternal(Annotation annotation) { 82 checkNotNull(annotation, "annotation"); 83 checkNotAnnotated(); 84 return setBinding(binding.withKey( 85 Key.get(this.binding.getKey().getTypeLiteral(), annotation))); 86 } 87 88 public void in(final Class<? extends Annotation> scopeAnnotation) { 89 checkNotNull(scopeAnnotation, "scopeAnnotation"); 90 checkNotScoped(); 91 setBinding(getBinding().withScoping(Scoping.forAnnotation(scopeAnnotation))); 92 } 93 94 public void in(final Scope scope) { 95 checkNotNull(scope, "scope"); 96 checkNotScoped(); 97 setBinding(getBinding().withScoping(Scoping.forInstance(scope))); 98 } 99 100 public void asEagerSingleton() { 101 checkNotScoped(); 102 setBinding(getBinding().withScoping(Scoping.EAGER_SINGLETON)); 103 } 104 105 protected boolean keyTypeIsSet() { 106 return !Void.class.equals(binding.getKey().getTypeLiteral().getType()); 107 } 108 109 protected void checkNotTargetted() { 110 if (!(binding instanceof UntargettedBindingImpl)) { 111 binder.addError(IMPLEMENTATION_ALREADY_SET); 112 } 113 } 114 115 protected void checkNotAnnotated() { 116 if (binding.getKey().getAnnotationType() != null) { 117 binder.addError(ANNOTATION_ALREADY_SPECIFIED); 118 } 119 } 120 121 protected void checkNotScoped() { 122 // Scoping isn't allowed when we have only one instance. 123 if (binding instanceof InstanceBinding) { 124 binder.addError(SINGLE_INSTANCE_AND_SCOPE); 125 return; 126 } 127 128 if (binding.getScoping().isExplicitlyScoped()) { 129 binder.addError(SCOPE_ALREADY_SET); 130 } 131 } 132}