org.springframework.context.annotation.ClassPathBeanDefinitionScanner Maven / Gradle / Ivy
/*
* Copyright 2002-2014 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.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.env.Environment;
import org.springframework.core.env.EnvironmentCapable;
import org.springframework.core.env.StandardEnvironment;
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 ({@code BeanFactory}
* or {@code ApplicationContext}).
*
* 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.
*
*
Also supports Java EE 6's {@link javax.annotation.ManagedBean} and
* JSR-330's {@link javax.inject.Named} annotations, if available.
*
* @author Mark Fisher
* @author Juergen Hoeller
* @author Chris Beams
* @since 2.5
* @see AnnotationConfigApplicationContext#scan
* @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 {@code ClassPathBeanDefinitionScanner} for the given bean factory.
* @param registry the {@code BeanFactory} to load bean definitions into, in the form
* of a {@code BeanDefinitionRegistry}
*/
public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry) {
this(registry, true);
}
/**
* Create a new {@code ClassPathBeanDefinitionScanner} for the given bean factory.
*
If the passed-in bean factory does not only implement the
* {@code BeanDefinitionRegistry} interface but also the {@code ResourceLoader}
* interface, it will be used as default {@code ResourceLoader} as well. This will
* usually be the case for {@link org.springframework.context.ApplicationContext}
* implementations.
*
If given a plain {@code BeanDefinitionRegistry}, the default {@code ResourceLoader}
* will be a {@link org.springframework.core.io.support.PathMatchingResourcePatternResolver}.
*
If the the passed-in bean factory also implements {@link EnvironmentCapable} its
* environment will be used by this reader. Otherwise, the reader will initialize and
* use a {@link org.springframework.core.env.StandardEnvironment}. All
* {@code ApplicationContext} implementations are {@code EnvironmentCapable}, while
* normal {@code BeanFactory} implementations are not.
* @param registry the {@code BeanFactory} to load bean definitions into, in the form
* of a {@code 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
* @see #setEnvironment
*/
public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters) {
this(registry, useDefaultFilters, getOrCreateEnvironment(registry));
}
/**
* Create a new {@code ClassPathBeanDefinitionScanner} for the given bean factory and
* using the given {@link Environment} when evaluating bean definition profile metadata.
*
If the passed-in bean factory does not only implement the {@code
* BeanDefinitionRegistry} interface but also the {@link ResourceLoader} interface, it
* will be used as default {@code ResourceLoader} as well. This will usually be the
* case for {@link org.springframework.context.ApplicationContext} implementations.
*
If given a plain {@code BeanDefinitionRegistry}, the default {@code ResourceLoader}
* will be a {@link org.springframework.core.io.support.PathMatchingResourcePatternResolver}.
* @param registry the {@code BeanFactory} to load bean definitions into, in the form
* of a {@code 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
* @param environment the Spring {@link Environment} to use when evaluating bean
* definition profile metadata
* @since 3.1
* @see #setResourceLoader
*/
public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters, Environment environment) {
super(useDefaultFilters, environment);
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());
}
/**
* Return the defaults to use for detected beans (never {@code null}).
* @since 4.1
*/
public BeanDefinitionDefaults getBeanDefinitionDefaults() {
return this.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.
*
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.
*
The default is an {@link AnnotationScopeMetadataResolver}.
* @see #setScopedProxyMode
*/
public void setScopeMetadataResolver(ScopeMetadataResolver scopeMetadataResolver) {
this.scopeMetadataResolver = (scopeMetadataResolver != null ? scopeMetadataResolver : new AnnotationScopeMetadataResolver());
}
/**
* Specify the proxy behavior for non-singleton scoped beans.
* Note that this will override any custom "scopeMetadataResolver" setting.
*
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.
*
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.
*
This method does not register an annotation config processor
* but rather leaves this up to the caller.
* @param basePackages the packages to check for annotated classes
* @return set of beans registered if any for tooling registration purposes (never {@code null})
*/
protected Set doScan(String... basePackages) {
Assert.notEmpty(basePackages, "At least one base package must be specified");
Set beanDefinitions = new LinkedHashSet();
for (String basePackage : basePackages) {
Set candidates = findCandidateComponents(basePackage);
for (BeanDefinition candidate : candidates) {
ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(candidate);
candidate.setScope(scopeMetadata.getScopeName());
String beanName = this.beanNameGenerator.generateBeanName(candidate, this.registry);
if (candidate instanceof AbstractBeanDefinition) {
postProcessBeanDefinition((AbstractBeanDefinition) candidate, beanName);
}
if (candidate instanceof AnnotatedBeanDefinition) {
AnnotationConfigUtils.processCommonDefinitionAnnotations((AnnotatedBeanDefinition) candidate);
}
if (checkCandidate(beanName, candidate)) {
BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
definitionHolder = AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
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.
* 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} if the bean can be registered as-is;
* {@code false} if it should be skipped because there is an
* existing, compatible bean definition for the specified name
* @throws ConflictingBeanDefinitionException 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 ConflictingBeanDefinitionException("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.
*
The default implementation considers them as compatible when the existing
* bean definition comes from the same source or from a non-scanning source.
* @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 ScannedGenericBeanDefinition) || // explicitly registered overriding bean
newDefinition.getSource().equals(existingDefinition.getSource()) || // scanned same file twice
newDefinition.equals(existingDefinition)); // scanned equivalent class twice
}
/**
* Get the Environment from the given registry if possible, otherwise return a new
* StandardEnvironment.
*/
private static Environment getOrCreateEnvironment(BeanDefinitionRegistry registry) {
Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
if (registry instanceof EnvironmentCapable) {
return ((EnvironmentCapable) registry).getEnvironment();
}
return new StandardEnvironment();
}
}