spring Lazy 源码

spring Lazy 代码

文件路径：/spring-context/src/main/java/org/springframework/context/annotation/Lazy.java

/*
 * Copyright 2002-2021 the original author or authors.
 *
 * 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
 *
 *      https://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 org.springframework.context.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Indicates whether a bean is to be lazily initialized.
 *
 * <p>May be used on any class directly or indirectly annotated with {@link
 * org.springframework.stereotype.Component @Component} or on methods annotated with
 * {@link Bean @Bean}.
 *
 * <p>If this annotation is not present on a {@code @Component} or {@code @Bean} definition,
 * eager initialization will occur. If present and set to {@code true}, the {@code @Bean} or
 * {@code @Component} will not be initialized until referenced by another bean or explicitly
 * retrieved from the enclosing {@link org.springframework.beans.factory.BeanFactory
 * BeanFactory}. If present and set to {@code false}, the bean will be instantiated on
 * startup by bean factories that perform eager initialization of singletons.
 *
 * <p>If Lazy is present on a {@link Configuration @Configuration} class, this
 * indicates that all {@code @Bean} methods within that {@code @Configuration}
 * should be lazily initialized. If {@code @Lazy} is present and false on a {@code @Bean}
 * method within a {@code @Lazy}-annotated {@code @Configuration} class, this indicates
 * overriding the 'default lazy' behavior and that the bean should be eagerly initialized.
 *
 * <p>In addition to its role for component initialization, this annotation may also be placed
 * on injection points marked with {@link org.springframework.beans.factory.annotation.Autowired}
 * or {@link jakarta.inject.Inject}: In that context, it leads to the creation of a
 * lazy-resolution proxy for all affected dependencies, as an alternative to using
 * {@link org.springframework.beans.factory.ObjectFactory} or {@link jakarta.inject.Provider}.
 * Please note that such a lazy-resolution proxy will always be injected; if the target
 * dependency does not exist, you will only be able to find out through an exception on
 * invocation. As a consequence, such an injection point results in unintuitive behavior
 * for optional dependencies. For a programmatic equivalent, allowing for lazy references
 * with more sophistication, consider {@link org.springframework.beans.factory.ObjectProvider}.
 *
 * @author Chris Beams
 * @author Juergen Hoeller
 * @since 3.0
 * @see Primary
 * @see Bean
 * @see Configuration
 * @see org.springframework.stereotype.Component
 */
@Target({ElementType.TYPE, ElementType.METHOD, ElementType.CONSTRUCTOR, ElementType.PARAMETER, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Lazy {

	/**
	 * Whether lazy initialization should occur.
	 */
	boolean value() default true;

}

相关信息

spring 源码目录

相关文章

spring AdviceMode 源码

spring AdviceModeImportSelector 源码

spring AnnotatedBeanDefinitionReader 源码

spring AnnotationBeanNameGenerator 源码

spring AnnotationConfigApplicationContext 源码

spring AnnotationConfigBeanDefinitionParser 源码

spring AnnotationConfigRegistry 源码

spring AnnotationConfigUtils 源码

spring AnnotationScopeMetadataResolver 源码

spring AspectJAutoProxyRegistrar 源码