/*
* Copyright 2002-2008 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.
*/
package org.springframework.context.annotation;
import java.util.LinkedHashSet;
import java.util.Set;
import org.springframework.aop.scope.ScopedProxyUtils;
import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionDefaults;
import org.springframework.beans.factory.support.BeanDefinitionReaderUtils;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.core.io.ResourceLoader;
import org.springframework.util.Assert;
import org.springframework.util.PatternMatchUtils;
/**
* A bean definition scanner that detects bean candidates on the classpath,
* registering corresponding bean definitions with a given registry (BeanFactory
* or ApplicationContext).
*
* <p>Candidate classes are detected through configurable type filters. The
* default filters include classes that are annotated with Spring's
* {@link org.springframework.stereotype.Component @Component},
* {@link org.springframework.stereotype.Repository @Repository},
* {@link org.springframework.stereotype.Service @Service}, or
* {@link org.springframework.stereotype.Controller @Controller} stereotype.
*
* @author Mark Fisher
* @author Juergen Hoeller
* @since 2.5
* @see org.springframework.stereotype.Component
* @see org.springframework.stereotype.Repository
* @see org.springframework.stereotype.Service
* @see org.springframework.stereotype.Controller
*/
public class ClassPathBeanDefinitionScanner extends ClassPathScanningCandidateComponentProvider {
private final BeanDefinitionRegistry registry;
private BeanDefinitionDefaults beanDefinitionDefaults = new BeanDefinitionDefaults();
private String[] autowireCandidatePatterns;
private BeanNameGenerator beanNameGenerator = new AnnotationBeanNameGenerator();
private ScopeMetadataResolver scopeMetadataResolver = new AnnotationScopeMetadataResolver();
private boolean includeAnnotationConfig = true;
/**
* Create a new ClassPathBeanDefinitionScanner for the given bean factory.
* @param registry the BeanFactory to load bean definitions into,
* in the form of a BeanDefinitionRegistry
*/
public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry) {
this(registry, true);
}
/**
* Create a new ClassPathBeanDefinitionScanner for the given bean factory.
* <p>If the passed-in bean factory does not only implement the BeanDefinitionRegistry
* interface but also the ResourceLoader interface, it will be used as default
* ResourceLoader as well. This will usually be the case for
* {@link org.springframework.context.ApplicationContext} implementations.
* <p>If given a plain BeanDefinitionRegistry, the default ResourceLoader will be a
* {@link org.springframework.core.io.support.PathMatchingResourcePatternResolver}.
* @param registry the BeanFactory to load bean definitions into,
* in the form of a BeanDefinitionRegistry
* @param useDefaultFilters whether to include the default filters for the
* {@link org.springframework.stereotype.Component @Component},
* {@link org.springframework.stereotype.Repository @Repository},
* {@link org.springframework.stereotype.Service @Service}, and
* {@link org.springframework.stereotype.Controller @Controller} stereotype
* annotations.
* @see #setResourceLoader
*/
public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters) {
super(useDefaultFilters);
Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
this.registry = registry;
// Determine ResourceLoader to use.
if (this.registry instanceof ResourceLoader) {
setResourceLoader((ResourceLoader) this.registry);
}
}
/**
* Return the BeanDefinitionRegistry that this scanner operates on.
*/
public final BeanDefinitionRegistry getRegistry() {
return this.registry;
}
/**
* Set the defaults to use for detected beans.
* @see BeanDefinitionDefaults
*/
public void setBeanDefinitionDefaults(BeanDefinitionDefaults beanDefinitionDefaults) {
this.beanDefinitionDefaults =
(beanDefinitionDefaults != null ? beanDefinitionDefaults : new BeanDefinitionDefaults());
}
/**
* Set the name-matching patterns for determining autowire candidates.
* @param autowireCandidatePatterns the patterns to match against
*/
public void setAutowireCandidatePatterns(String[] autowireCandidatePatterns) {
this.autowireCandidatePatterns = autowireCandidatePatterns;
}
/**
* Set the BeanNameGenerator to use for detected bean classes.
* <p>Default is a {@link AnnotationBeanNameGenerator}.
*/
public void setBeanNameGenerator(BeanNameGenerator beanNameGenerator) {
this.beanNameGenerator = (beanNameGenerator != null ? beanNameGenerator : new AnnotationBeanNameGenerator());
}
/**
* Set the ScopeMetadataResolver to use for detected bean classes.
* Note that this will override any custom "scopedProxyMode" setting.
* <p>The default is an {@link AnnotationScopeMetadataResolver}.
* @see #setScopedProxyMode
*/
public void setScopeMetadataResolver(ScopeMetadataResolver scopeMetadataResolver) {
this.scopeMetadataResolver = scopeMetadataResolver;
}
/**
* Specify the proxy behavior for non-singleton scoped beans.
* Note that this will override any custom "scopeMetadataResolver" setting.
* <p>The default is {@link ScopedProxyMode#NO}.
* @see #setScopeMetadataResolver
*/
public void setScopedProxyMode(ScopedProxyMode scopedProxyMode) {
this.scopeMetadataResolver = new AnnotationScopeMetadataResolver(scopedProxyMode);
}
/**
* Specify whether to register annotation config post-processors.
* <p>The default is to register the post-processors. Turn this off
* to be able to ignore the annotations or to process them differently.
*/
public void setIncludeAnnotationConfig(boolean includeAnnotationConfig) {
this.includeAnnotationConfig = includeAnnotationConfig;
}
/**
* Perform a scan within the specified base packages.
* @param basePackages the packages to check for annotated classes
* @return number of beans registered
*/
public int scan(String... basePackages) {
int beanCountAtScanStart = this.registry.getBeanDefinitionCount();
doScan(basePackages);
// Register annotation config processors, if necessary.
if (this.includeAnnotationConfig) {
AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);
}
return this.registry.getBeanDefinitionCount() - beanCountAtScanStart;
}
/**
* Perform a scan within the specified base packages,
* returning the registered bean definitions.
* <p>This method does <i>not</i> register an annotation config processor
* but rather leaves this up to the caller.
* @param basePackages the packages to check for annotated classes
* @return number of beans registered
*/
protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
Set<BeanDefinitionHolder> beanDefinitions = new LinkedHashSet<BeanDefinitionHolder>();
for (int i = 0; i < basePackages.length; i++) {
Set<BeanDefinition> candidates = findCandidateComponents(basePackages[i]);
for (BeanDefinition candidate : candidates) {
String beanName = this.beanNameGenerator.generateBeanName(candidate, this.registry);
if (candidate instanceof AbstractBeanDefinition) {
postProcessBeanDefinition((AbstractBeanDefinition) candidate, beanName);
}
ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(candidate);
if (checkCandidate(beanName, candidate)) {
BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
definitionHolder = applyScope(definitionHolder, scopeMetadata);
beanDefinitions.add(definitionHolder);
registerBeanDefinition(definitionHolder, this.registry);
}
}
}
return beanDefinitions;
}
/**
* Apply further settings to the given bean definition,
* beyond the contents retrieved from scanning the component class.
* @param beanDefinition the scanned bean definition
* @param beanName the generated bean name for the given bean
*/
protected void postProcessBeanDefinition(AbstractBeanDefinition beanDefinition, String beanName) {
beanDefinition.applyDefaults(this.beanDefinitionDefaults);
if (this.autowireCandidatePatterns != null) {
beanDefinition.setAutowireCandidate(PatternMatchUtils.simpleMatch(this.autowireCandidatePatterns, beanName));
}
}
/**
* Register the specified bean with the given registry.
* <p>Can be overridden in subclasses, e.g. to adapt the registration
* process or to register further bean definitions for each scanned bean.
* @param definitionHolder the bean definition plus bean name for the bean
* @param registry the BeanDefinitionRegistry to register the bean with
*/
protected void registerBeanDefinition(BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry) {
BeanDefinitionReaderUtils.registerBeanDefinition(definitionHolder, registry);
}
/**
* Check the given candidate's bean name, determining whether the corresponding
* bean definition needs to be registered or conflicts with an existing definition.
* @param beanName the suggested name for the bean
* @param beanDefinition the corresponding bean definition
* @return <code>true</code> if the bean can be registered as-is;
* <code>false</code> if it should be skipped because there is an
* existing, compatible bean definition for the specified name
* @throws IllegalStateException if an existing, incompatible
* bean definition has been found for the specified name
*/
protected boolean checkCandidate(String beanName, BeanDefinition beanDefinition) throws IllegalStateException {
if (!this.registry.containsBeanDefinition(beanName)) {
return true;
}
BeanDefinition existingDef = this.registry.getBeanDefinition(beanName);
BeanDefinition originatingDef = existingDef.getOriginatingBeanDefinition();
if (originatingDef != null) {
existingDef = originatingDef;
}
if (isCompatible(beanDefinition, existingDef)) {
return false;
}
throw new IllegalStateException("Annotation-specified bean name '" + beanName +
"' for bean class [" + beanDefinition.getBeanClassName() + "] conflicts with existing, " +
"non-compatible bean definition of same name and class [" + existingDef.getBeanClassName() + "]");
}
/**
* Determine whether the given new bean definition is compatible with
* the given existing bean definition.
* <p>The default implementation simply considers them as compatible
* when the bean class name matches.
* @param newDefinition the new bean definition, originated from scanning
* @param existingDefinition the existing bean definition, potentially an
* explicitly defined one or a previously generated one from scanning
* @return whether the definitions are considered as compatible, with the
* new definition to be skipped in favor of the existing definition
*/
protected boolean isCompatible(BeanDefinition newDefinition, BeanDefinition existingDefinition) {
return (!(existingDefinition instanceof AnnotatedBeanDefinition) || // explicitly registered overriding bean
newDefinition.getSource().equals(existingDefinition.getSource()) || // scanned same file twice
newDefinition.equals(existingDefinition)); // scanned equivalent class twice
}
/**
* Apply the specified scope to the given bean definition.
* @param definitionHolder the bean definition to configure
* @param scopeMetadata the corresponding scope metadata
* @return the final bean definition to use (potentially a proxy)
*/
private BeanDefinitionHolder applyScope(BeanDefinitionHolder definitionHolder, ScopeMetadata scopeMetadata) {
String scope = scopeMetadata.getScopeName();
ScopedProxyMode scopedProxyMode = scopeMetadata.getScopedProxyMode();
definitionHolder.getBeanDefinition().setScope(scope);
if (BeanDefinition.SCOPE_SINGLETON.equals(scope) || BeanDefinition.SCOPE_PROTOTYPE.equals(scope) ||
scopedProxyMode.equals(ScopedProxyMode.NO)) {
return definitionHolder;
}
boolean proxyTargetClass = scopedProxyMode.equals(ScopedProxyMode.TARGET_CLASS);
return ScopedProxyCreator.createScopedProxy(definitionHolder, this.registry, proxyTargetClass);
}
/**
* Inner factory class used to just introduce an AOP framework dependency
* when actually creating a scoped proxy.
*/
private static class ScopedProxyCreator {
public static BeanDefinitionHolder createScopedProxy(
BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry, boolean proxyTargetClass) {
return ScopedProxyUtils.createScopedProxy(definitionHolder, registry, proxyTargetClass);
}
}
}