| /** |
| * Copyright (C) 2006 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; |
| |
| import com.google.inject.util.StackTraceElements; |
| import java.lang.reflect.Constructor; |
| import java.lang.reflect.InvocationTargetException; |
| |
| /** |
| * Injects constructors. |
| * |
| * @author crazybob@google.com (Bob Lee) |
| */ |
| class ConstructorInjector<T> { |
| |
| final Class<T> implementation; |
| final InjectorImpl.SingleMemberInjector[] memberInjectors; |
| final InjectorImpl.SingleParameterInjector<?>[] parameterInjectors; |
| final ConstructionProxy<T> constructionProxy; |
| |
| ConstructorInjector(InjectorImpl injector, Class<T> implementation) { |
| this.implementation = implementation; |
| Constructor<T> constructor = findConstructorIn(injector, implementation); |
| parameterInjectors = createParameterInjector(injector, constructor); |
| memberInjectors = injector.injectors.get(implementation) |
| .toArray(new InjectorImpl.SingleMemberInjector[0]); |
| constructionProxy = injector.constructionProxyFactory.get(constructor); |
| } |
| |
| /** |
| * Used to create an invalid injector. |
| */ |
| private ConstructorInjector() { |
| implementation = null; |
| memberInjectors = null; |
| parameterInjectors = null; |
| constructionProxy = null; |
| } |
| |
| InjectorImpl.SingleParameterInjector<?>[] createParameterInjector( |
| InjectorImpl injector, Constructor<T> constructor) { |
| try { |
| return constructor.getParameterTypes().length == 0 |
| ? null // default constructor. |
| : injector.getParametersInjectors( |
| constructor, |
| constructor.getParameterAnnotations(), |
| constructor.getGenericParameterTypes() |
| ); |
| } |
| catch (InjectorImpl.MissingDependencyException e) { |
| e.handle(injector.errorHandler); |
| return null; |
| } |
| } |
| |
| private Constructor<T> findConstructorIn(InjectorImpl injector, |
| Class<T> implementation) { |
| Constructor<T> found = null; |
| @SuppressWarnings("unchecked") |
| Constructor<T>[] constructors |
| = (Constructor<T>[]) implementation.getDeclaredConstructors(); |
| for (Constructor<T> constructor : constructors) { |
| Inject inject = constructor.getAnnotation(Inject.class); |
| if (inject != null) { |
| if (inject.optional()) { |
| injector.errorHandler.handle( |
| StackTraceElements.forMember(constructor), |
| ErrorMessages.OPTIONAL_CONSTRUCTOR); |
| } |
| |
| if (found != null) { |
| injector.errorHandler.handle( |
| StackTraceElements.forMember(found), |
| ErrorMessages.TOO_MANY_CONSTRUCTORS); |
| return InjectorImpl.invalidConstructor(); |
| } |
| found = constructor; |
| } |
| } |
| if (found != null) { |
| return found; |
| } |
| |
| // If no annotated constructor is found, look for a no-arg constructor |
| // instead. |
| try { |
| return implementation.getDeclaredConstructor(); |
| } |
| catch (NoSuchMethodException e) { |
| injector.errorHandler.handle( |
| StackTraceElements.forMember( |
| implementation.getDeclaredConstructors()[0]), |
| ErrorMessages.MISSING_CONSTRUCTOR, |
| implementation); |
| return InjectorImpl.invalidConstructor(); |
| } |
| } |
| |
| /** |
| * Construct an instance. Returns {@code Object} instead of {@code T} because |
| * it may return a proxy. |
| */ |
| Object construct(InternalContext context, Class<?> expectedType) { |
| ConstructionContext<T> constructionContext |
| = context.getConstructionContext(this); |
| |
| // We have a circular reference between constructors. Return a proxy. |
| if (constructionContext.isConstructing()) { |
| // TODO (crazybob): if we can't proxy this object, can we proxy the |
| // other object? |
| return constructionContext.createProxy(expectedType); |
| } |
| |
| // If we're re-entering this factory while injecting fields or methods, |
| // return the same instance. This prevents infinite loops. |
| T t = constructionContext.getCurrentReference(); |
| if (t != null) { |
| return t; |
| } |
| |
| try { |
| // First time through... |
| constructionContext.startConstruction(); |
| try { |
| Object[] parameters |
| = InjectorImpl.getParameters(context, parameterInjectors); |
| t = constructionProxy.newInstance(parameters); |
| constructionContext.setProxyDelegates(t); |
| } |
| finally { |
| constructionContext.finishConstruction(); |
| } |
| |
| // Store reference. If an injector re-enters this factory, they'll |
| // get the same reference. |
| constructionContext.setCurrentReference(t); |
| |
| // Inject fields and methods. |
| for (InjectorImpl.SingleMemberInjector injector : memberInjectors) { |
| injector.inject(context, t); |
| } |
| |
| return t; |
| } |
| catch (InvocationTargetException e) { |
| throw new RuntimeException(e); |
| } |
| finally { |
| constructionContext.removeCurrentReference(); |
| } |
| } |
| |
| /** |
| * Returns an invalid constructor. This enables us to keep running and |
| * reporting legitimate errors. |
| */ |
| static <T> ConstructorInjector<T> invalidConstructor() { |
| return new ConstructorInjector<T>() { |
| Object construct(InternalContext context, Class<?> expectedType) { |
| throw new UnsupportedOperationException(); |
| } |
| public T get() { |
| throw new UnsupportedOperationException(); |
| } |
| }; |
| } |
| } |