/*
 * Copyright 2002-2018 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
 *
 *      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.
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package org.springframework.context.annotation;

import java.io.IOException;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.core.Conventions;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.core.annotation.Order;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.StandardAnnotationMetadata;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;

Utilities for identifying Configuration classes.
Author:Chris Beams, Juergen Hoeller
Since:3.1
/** * Utilities for identifying {@link Configuration} classes. * * @author Chris Beams * @author Juergen Hoeller * @since 3.1 */
abstract class ConfigurationClassUtils { private static final String CONFIGURATION_CLASS_FULL = "full"; private static final String CONFIGURATION_CLASS_LITE = "lite"; private static final String CONFIGURATION_CLASS_ATTRIBUTE = Conventions.getQualifiedAttributeName(ConfigurationClassPostProcessor.class, "configurationClass"); private static final String ORDER_ATTRIBUTE = Conventions.getQualifiedAttributeName(ConfigurationClassPostProcessor.class, "order"); private static final Log logger = LogFactory.getLog(ConfigurationClassUtils.class); private static final Set<String> candidateIndicators = new HashSet<>(8); static { candidateIndicators.add(Component.class.getName()); candidateIndicators.add(ComponentScan.class.getName()); candidateIndicators.add(Import.class.getName()); candidateIndicators.add(ImportResource.class.getName()); }
Check whether the given bean definition is a candidate for a configuration class (or a nested component class declared within a configuration/component class, to be auto-registered as well), and mark it accordingly.
Params:
  • beanDef – the bean definition to check
  • metadataReaderFactory – the current factory in use by the caller
Returns:whether the candidate qualifies as (any kind of) configuration class
/** * Check whether the given bean definition is a candidate for a configuration class * (or a nested component class declared within a configuration/component class, * to be auto-registered as well), and mark it accordingly. * @param beanDef the bean definition to check * @param metadataReaderFactory the current factory in use by the caller * @return whether the candidate qualifies as (any kind of) configuration class */
public static boolean checkConfigurationClassCandidate( BeanDefinition beanDef, MetadataReaderFactory metadataReaderFactory) { String className = beanDef.getBeanClassName(); if (className == null || beanDef.getFactoryMethodName() != null) { return false; } AnnotationMetadata metadata; if (beanDef instanceof AnnotatedBeanDefinition && className.equals(((AnnotatedBeanDefinition) beanDef).getMetadata().getClassName())) { // Can reuse the pre-parsed metadata from the given BeanDefinition... metadata = ((AnnotatedBeanDefinition) beanDef).getMetadata(); } else if (beanDef instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) beanDef).hasBeanClass()) { // Check already loaded Class if present... // since we possibly can't even load the class file for this Class. Class<?> beanClass = ((AbstractBeanDefinition) beanDef).getBeanClass(); metadata = new StandardAnnotationMetadata(beanClass, true); } else { try { MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(className); metadata = metadataReader.getAnnotationMetadata(); } catch (IOException ex) { if (logger.isDebugEnabled()) { logger.debug("Could not find class file for introspecting configuration annotations: " + className, ex); } return false; } } if (isFullConfigurationCandidate(metadata)) { beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_FULL); } else if (isLiteConfigurationCandidate(metadata)) { beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_LITE); } else { return false; } // It's a full or lite configuration candidate... Let's determine the order value, if any. Integer order = getOrder(metadata); if (order != null) { beanDef.setAttribute(ORDER_ATTRIBUTE, order); } return true; }
Check the given metadata for a configuration class candidate (or nested component class declared within a configuration/component class).
Params:
  • metadata – the metadata of the annotated class
Returns:true if the given class is to be registered as a reflection-detected bean definition; false otherwise
/** * Check the given metadata for a configuration class candidate * (or nested component class declared within a configuration/component class). * @param metadata the metadata of the annotated class * @return {@code true} if the given class is to be registered as a * reflection-detected bean definition; {@code false} otherwise */
public static boolean isConfigurationCandidate(AnnotationMetadata metadata) { return (isFullConfigurationCandidate(metadata) || isLiteConfigurationCandidate(metadata)); }
Check the given metadata for a full configuration class candidate (i.e. a class annotated with @Configuration).
Params:
  • metadata – the metadata of the annotated class
Returns:true if the given class is to be processed as a full configuration class, including cross-method call interception
/** * Check the given metadata for a full configuration class candidate * (i.e. a class annotated with {@code @Configuration}). * @param metadata the metadata of the annotated class * @return {@code true} if the given class is to be processed as a full * configuration class, including cross-method call interception */
public static boolean isFullConfigurationCandidate(AnnotationMetadata metadata) { return metadata.isAnnotated(Configuration.class.getName()); }
Check the given metadata for a lite configuration class candidate (e.g. a class annotated with @Component or just having @Import declarations or @Bean methods).
Params:
  • metadata – the metadata of the annotated class
Returns:true if the given class is to be processed as a lite configuration class, just registering it and scanning it for @Bean methods
/** * Check the given metadata for a lite configuration class candidate * (e.g. a class annotated with {@code @Component} or just having * {@code @Import} declarations or {@code @Bean methods}). * @param metadata the metadata of the annotated class * @return {@code true} if the given class is to be processed as a lite * configuration class, just registering it and scanning it for {@code @Bean} methods */
public static boolean isLiteConfigurationCandidate(AnnotationMetadata metadata) { // Do not consider an interface or an annotation... if (metadata.isInterface()) { return false; } // Any of the typical annotations found? for (String indicator : candidateIndicators) { if (metadata.isAnnotated(indicator)) { return true; } } // Finally, let's look for @Bean methods... try { return metadata.hasAnnotatedMethods(Bean.class.getName()); } catch (Throwable ex) { if (logger.isDebugEnabled()) { logger.debug("Failed to introspect @Bean methods on class [" + metadata.getClassName() + "]: " + ex); } return false; } }
Determine whether the given bean definition indicates a full @Configuration class, through checking checkConfigurationClassCandidate's metadata marker.
/** * Determine whether the given bean definition indicates a full {@code @Configuration} * class, through checking {@link #checkConfigurationClassCandidate}'s metadata marker. */
public static boolean isFullConfigurationClass(BeanDefinition beanDef) { return CONFIGURATION_CLASS_FULL.equals(beanDef.getAttribute(CONFIGURATION_CLASS_ATTRIBUTE)); }
Determine whether the given bean definition indicates a lite @Configuration class, through checking checkConfigurationClassCandidate's metadata marker.
/** * Determine whether the given bean definition indicates a lite {@code @Configuration} * class, through checking {@link #checkConfigurationClassCandidate}'s metadata marker. */
public static boolean isLiteConfigurationClass(BeanDefinition beanDef) { return CONFIGURATION_CLASS_LITE.equals(beanDef.getAttribute(CONFIGURATION_CLASS_ATTRIBUTE)); }
Determine the order for the given configuration class metadata.
Params:
  • metadata – the metadata of the annotated class
Returns:the @Order annotation value on the configuration class, or Ordered.LOWEST_PRECEDENCE if none declared
Since:5.0
/** * Determine the order for the given configuration class metadata. * @param metadata the metadata of the annotated class * @return the {@code @Order} annotation value on the configuration class, * or {@code Ordered.LOWEST_PRECEDENCE} if none declared * @since 5.0 */
@Nullable public static Integer getOrder(AnnotationMetadata metadata) { Map<String, Object> orderAttributes = metadata.getAnnotationAttributes(Order.class.getName()); return (orderAttributes != null ? ((Integer) orderAttributes.get(AnnotationUtils.VALUE)) : null); }
Determine the order for the given configuration class bean definition, as set by checkConfigurationClassCandidate.
Params:
  • beanDef – the bean definition to check
Returns:the @Order annotation value on the configuration class, or Ordered.LOWEST_PRECEDENCE if none declared
Since:4.2
/** * Determine the order for the given configuration class bean definition, * as set by {@link #checkConfigurationClassCandidate}. * @param beanDef the bean definition to check * @return the {@link Order @Order} annotation value on the configuration class, * or {@link Ordered#LOWEST_PRECEDENCE} if none declared * @since 4.2 */
public static int getOrder(BeanDefinition beanDef) { Integer order = (Integer) beanDef.getAttribute(ORDER_ATTRIBUTE); return (order != null ? order : Ordered.LOWEST_PRECEDENCE); } }