| /** |
| * Copyright (C) 2007 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.spi; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkState; |
| import com.google.common.collect.Lists; |
| import com.google.inject.Binder; |
| import com.google.inject.Key; |
| import com.google.inject.Module; |
| import com.google.inject.Provider; |
| import com.google.inject.Provides; |
| import com.google.inject.TypeLiteral; |
| import com.google.inject.binder.AnnotatedBindingBuilder; |
| import com.google.inject.internal.Annotations; |
| import com.google.inject.internal.Errors; |
| import com.google.inject.internal.TypeResolver; |
| import com.google.inject.util.Modules; |
| import java.lang.annotation.Annotation; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Type; |
| import java.util.List; |
| |
| /** |
| * Creates bindings to methods annotated with {@literal @}{@link Provides}. Use the scope and |
| * binding annotations on the provider method to configure the binding. |
| */ |
| class ProviderMethods { |
| |
| /** |
| * Returns a module which creates bindings for provider methods from the |
| * given object. |
| */ |
| static Module from(Object providers) { |
| // avoid infinite recursion, since installing a module always installs itself |
| if (providers instanceof ProviderMethodsModule) { |
| return Modules.EMPTY_MODULE; |
| } |
| |
| return new ProviderMethodsModule(providers); |
| } |
| |
| static class ProviderMethodsModule implements Module { |
| final Object providers; |
| final TypeResolver typeResolver; |
| Binder binder; |
| |
| ProviderMethodsModule(Object providers) { |
| this.providers = checkNotNull(providers, "providers"); |
| this.typeResolver = new TypeResolver(providers.getClass()); |
| } |
| |
| public synchronized void configure(Binder binder) { |
| checkState(this.binder == null, "Re-entry is not allowed."); |
| |
| for (Class c = providers.getClass(); c != Object.class; c = c.getSuperclass()) { |
| for (Method method : c.getDeclaredMethods()) { |
| if (!method.isAnnotationPresent(Provides.class)) { |
| continue; |
| } |
| |
| this.binder = binder.withSource(method); |
| try { |
| bindProviderMethod(method); |
| } finally { |
| this.binder = null; |
| } |
| } |
| } |
| } |
| |
| <T> void bindProviderMethod(final Method method) { |
| Errors errors = new Errors(method); |
| |
| method.setAccessible(true); |
| |
| Class<? extends Annotation> scopeAnnotation |
| = Annotations.findScopeAnnotation(errors, method.getAnnotations()); |
| Annotation bindingAnnotation |
| = Annotations.findBindingAnnotation(errors, method, method.getAnnotations()); |
| |
| final List<Provider<?>> parameterProviders = findParameterProviders(errors, method); |
| |
| for (Message message : errors.getMessages()) { |
| binder.addError(message); |
| } |
| |
| // Define T as the method's return type. |
| @SuppressWarnings("unchecked") TypeLiteral<T> returnType |
| = (TypeLiteral<T>) TypeLiteral.get(typeResolver.getReturnType(method)); |
| |
| Provider<T> provider = new Provider<T>() { |
| public T get() { |
| Object[] parameters = new Object[parameterProviders.size()]; |
| for (int i = 0; i < parameters.length; i++) { |
| parameters[i] = parameterProviders.get(i).get(); |
| } |
| |
| try { |
| // We know this cast is safe becase T is the method's return type. |
| @SuppressWarnings({ "unchecked", "UnnecessaryLocalVariable" }) |
| T result = (T) method.invoke(providers, parameters); |
| return result; |
| } |
| catch (IllegalAccessException e) { |
| throw new AssertionError(e); |
| } |
| catch (InvocationTargetException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| }; |
| |
| AnnotatedBindingBuilder<T> builder = binder.bind(returnType); |
| |
| if (bindingAnnotation != null) { |
| builder.annotatedWith(bindingAnnotation); |
| } |
| |
| builder.toProvider(provider); |
| |
| if (scopeAnnotation != null) { |
| builder.in(scopeAnnotation); |
| } |
| } |
| |
| List<Provider<?>> findParameterProviders(Errors errors, Method method) { |
| List<Provider<?>> parameterProviders = Lists.newArrayList(); |
| |
| List<Type> parameterTypes = typeResolver.getParameterTypes(method); |
| Annotation[][] parameterAnnotations = method.getParameterAnnotations(); |
| for (int i = 0; i < parameterTypes.size(); i++) { |
| Type parameterType = parameterTypes.get(i); |
| Annotation bindingAnnotation |
| = Annotations.findBindingAnnotation(errors, method, parameterAnnotations[i]); |
| Key<?> key = bindingAnnotation == null ? Key.get(parameterType) |
| : Key.get(parameterType, bindingAnnotation); |
| Provider<?> provider = binder.getProvider(key); |
| parameterProviders.add(provider); |
| } |
| |
| return parameterProviders; |
| } |
| |
| @Override public boolean equals(Object o) { |
| return o instanceof ProviderMethodsModule |
| && ((ProviderMethodsModule) o).providers == providers; |
| } |
| |
| @Override public int hashCode() { |
| return providers.hashCode(); |
| } |
| } |
| } |