1 /* 2 * Copyright (C) 2006 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.spring; 18 19 import static com.google.common.base.Preconditions.checkNotNull; 20 21 import com.google.inject.Binder; 22 import com.google.inject.Inject; 23 import com.google.inject.Provider; 24 import com.google.inject.name.Names; 25 import org.springframework.beans.factory.BeanFactory; 26 import org.springframework.beans.factory.ListableBeanFactory; 27 28 /** 29 * Integrates Guice with Spring. 30 * 31 * @author crazybob@google.com (Bob Lee) 32 */ 33 public class SpringIntegration { SpringIntegration()34 private SpringIntegration() {} 35 36 /** 37 * Creates a provider which looks up objects from Spring using the given name. Expects a binding 38 * to {@link org.springframework.beans.factory.BeanFactory}. Example usage: 39 * 40 * <pre> 41 * bind(DataSource.class) 42 * .toProvider(fromSpring(DataSource.class, "dataSource")); 43 * </pre> 44 */ fromSpring(Class<T> type, String name)45 public static <T> Provider<T> fromSpring(Class<T> type, String name) { 46 return new InjectableSpringProvider<T>(type, name); 47 } 48 49 /** 50 * Binds all Spring beans from the given factory by name. For a Spring bean named "foo", this 51 * method creates a binding to the bean's type and {@code @Named("foo")}. 52 * 53 * @see com.google.inject.name.Named 54 * @see com.google.inject.name.Names#named(String) 55 */ bindAll(Binder binder, ListableBeanFactory beanFactory)56 public static void bindAll(Binder binder, ListableBeanFactory beanFactory) { 57 binder = binder.skipSources(SpringIntegration.class); 58 59 for (String name : beanFactory.getBeanDefinitionNames()) { 60 Class<?> type = beanFactory.getType(name); 61 bindBean(binder, beanFactory, name, type); 62 } 63 } 64 bindBean( Binder binder, ListableBeanFactory beanFactory, String name, Class<T> type)65 static <T> void bindBean( 66 Binder binder, ListableBeanFactory beanFactory, String name, Class<T> type) { 67 SpringProvider<T> provider = SpringProvider.newInstance(type, name); 68 try { 69 provider.initialize(beanFactory); 70 } catch (Exception e) { 71 binder.addError(e); 72 return; 73 } 74 75 binder.bind(type).annotatedWith(Names.named(name)).toProvider(provider); 76 } 77 78 static class SpringProvider<T> implements Provider<T> { 79 80 BeanFactory beanFactory; 81 boolean singleton; 82 final Class<T> type; 83 final String name; 84 SpringProvider(Class<T> type, String name)85 public SpringProvider(Class<T> type, String name) { 86 this.type = checkNotNull(type, "type"); 87 this.name = checkNotNull(name, "name"); 88 } 89 newInstance(Class<T> type, String name)90 static <T> SpringProvider<T> newInstance(Class<T> type, String name) { 91 return new SpringProvider<T>(type, name); 92 } 93 initialize(BeanFactory beanFactory)94 void initialize(BeanFactory beanFactory) { 95 this.beanFactory = beanFactory; 96 if (!beanFactory.isTypeMatch(name, type)) { 97 throw new ClassCastException( 98 "Spring bean named '" + name + "' does not implement " + type.getName() + "."); 99 } 100 singleton = beanFactory.isSingleton(name); 101 } 102 103 @Override get()104 public T get() { 105 return singleton ? getSingleton() : type.cast(beanFactory.getBean(name)); 106 } 107 108 volatile T instance; 109 getSingleton()110 private T getSingleton() { 111 if (instance == null) { 112 instance = type.cast(beanFactory.getBean(name)); 113 } 114 return instance; 115 } 116 } 117 118 static class InjectableSpringProvider<T> extends SpringProvider<T> { 119 InjectableSpringProvider(Class<T> type, String name)120 InjectableSpringProvider(Class<T> type, String name) { 121 super(type, name); 122 } 123 124 @Inject 125 @Override initialize(BeanFactory beanFactory)126 void initialize(BeanFactory beanFactory) { 127 super.initialize(beanFactory); 128 } 129 } 130 } 131