/* * Copyright 2002-2019 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.io.IOException; import java.lang.annotation.Annotation; import java.util.HashSet; import java.util.LinkedHashSet; import java.util.LinkedList; import java.util.List; import java.util.Set; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.beans.factory.BeanDefinitionStoreException; import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition; import org.springframework.beans.factory.annotation.AnnotatedGenericBeanDefinition; import org.springframework.beans.factory.annotation.Lookup; import org.springframework.beans.factory.config.BeanDefinition; import org.springframework.beans.factory.support.BeanDefinitionRegistry; import org.springframework.context.ResourceLoaderAware; import org.springframework.context.index.CandidateComponentsIndex; import org.springframework.context.index.CandidateComponentsIndexLoader; import org.springframework.core.annotation.AnnotationUtils; import org.springframework.core.env.Environment; import org.springframework.core.env.EnvironmentCapable; import org.springframework.core.env.StandardEnvironment; import org.springframework.core.io.Resource; import org.springframework.core.io.ResourceLoader; import org.springframework.core.io.support.PathMatchingResourcePatternResolver; import org.springframework.core.io.support.ResourcePatternResolver; import org.springframework.core.io.support.ResourcePatternUtils; import org.springframework.core.type.AnnotationMetadata; import org.springframework.core.type.classreading.CachingMetadataReaderFactory; import org.springframework.core.type.classreading.MetadataReader; import org.springframework.core.type.classreading.MetadataReaderFactory; import org.springframework.core.type.filter.AnnotationTypeFilter; import org.springframework.core.type.filter.AssignableTypeFilter; import org.springframework.core.type.filter.TypeFilter; import org.springframework.lang.Nullable; import org.springframework.stereotype.Component; import org.springframework.stereotype.Controller; import org.springframework.stereotype.Indexed; import org.springframework.stereotype.Repository; import org.springframework.stereotype.Service; import org.springframework.util.Assert; import org.springframework.util.ClassUtils; /** * A component provider that provides candidate components from a base package. Can * use {@link CandidateComponentsIndex the index} if it is available of scans the * classpath otherwise. Candidate components are identified by applying exclude and * include filters. {@link AnnotationTypeFilter}, {@link AssignableTypeFilter} include * filters on an annotation/superclass that are annotated with {@link Indexed} are * supported: if any other include filter is specified, the index is ignored and * classpath scanning is used instead. * *
This implementation is based on Spring's
* {@link org.springframework.core.type.classreading.MetadataReader MetadataReader}
* facility, backed by an ASM {@link org.springframework.asm.ClassReader ClassReader}.
*
* @author Mark Fisher
* @author Juergen Hoeller
* @author Ramnivas Laddad
* @author Chris Beams
* @author Stephane Nicoll
* @since 2.5
* @see org.springframework.core.type.classreading.MetadataReaderFactory
* @see org.springframework.core.type.AnnotationMetadata
* @see ScannedGenericBeanDefinition
* @see CandidateComponentsIndex
*/
public class ClassPathScanningCandidateComponentProvider implements EnvironmentCapable, ResourceLoaderAware {
static final String DEFAULT_RESOURCE_PATTERN = "**/*.class";
protected final Log logger = LogFactory.getLog(getClass());
private String resourcePattern = DEFAULT_RESOURCE_PATTERN;
private final List This will implicitly register all annotations that have the
* {@link Component @Component} meta-annotation including the
* {@link Repository @Repository}, {@link Service @Service}, and
* {@link Controller @Controller} stereotype annotations.
* Also supports Java EE 6's {@link javax.annotation.ManagedBean} and
* JSR-330's {@link javax.inject.Named} annotations, if available.
*
*/
@SuppressWarnings("unchecked")
protected void registerDefaultFilters() {
this.includeFilters.add(new AnnotationTypeFilter(Component.class));
ClassLoader cl = ClassPathScanningCandidateComponentProvider.class.getClassLoader();
try {
this.includeFilters.add(new AnnotationTypeFilter(
((Class extends Annotation>) ClassUtils.forName("javax.annotation.ManagedBean", cl)), false));
logger.trace("JSR-250 'javax.annotation.ManagedBean' found and supported for component scanning");
}
catch (ClassNotFoundException ex) {
// JSR-250 1.1 API (as included in Java EE 6) not available - simply skip.
}
try {
this.includeFilters.add(new AnnotationTypeFilter(
((Class extends Annotation>) ClassUtils.forName("javax.inject.Named", cl)), false));
logger.trace("JSR-330 'javax.inject.Named' annotation found and supported for component scanning");
}
catch (ClassNotFoundException ex) {
// JSR-330 API not available - simply skip.
}
}
/**
* Set the Environment to use when resolving placeholders and evaluating
* {@link Conditional @Conditional}-annotated component classes.
* The default is a {@link StandardEnvironment}.
* @param environment the Environment to use
*/
public void setEnvironment(Environment environment) {
Assert.notNull(environment, "Environment must not be null");
this.environment = environment;
this.conditionEvaluator = null;
}
@Override
public final Environment getEnvironment() {
if (this.environment == null) {
this.environment = new StandardEnvironment();
}
return this.environment;
}
/**
* Return the {@link BeanDefinitionRegistry} used by this scanner, if any.
*/
@Nullable
protected BeanDefinitionRegistry getRegistry() {
return null;
}
/**
* Set the {@link ResourceLoader} to use for resource locations.
* This will typically be a {@link ResourcePatternResolver} implementation.
* Default is a {@code PathMatchingResourcePatternResolver}, also capable of
* resource pattern resolving through the {@code ResourcePatternResolver} interface.
* @see org.springframework.core.io.support.ResourcePatternResolver
* @see org.springframework.core.io.support.PathMatchingResourcePatternResolver
*/
@Override
public void setResourceLoader(@Nullable ResourceLoader resourceLoader) {
this.resourcePatternResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
this.metadataReaderFactory = new CachingMetadataReaderFactory(resourceLoader);
this.componentsIndex = CandidateComponentsIndexLoader.loadIndex(this.resourcePatternResolver.getClassLoader());
}
/**
* Return the ResourceLoader that this component provider uses.
*/
public final ResourceLoader getResourceLoader() {
return getResourcePatternResolver();
}
private ResourcePatternResolver getResourcePatternResolver() {
if (this.resourcePatternResolver == null) {
this.resourcePatternResolver = new PathMatchingResourcePatternResolver();
}
return this.resourcePatternResolver;
}
/**
* Set the {@link MetadataReaderFactory} to use.
* Default is a {@link CachingMetadataReaderFactory} for the specified
* {@linkplain #setResourceLoader resource loader}.
* Call this setter method after {@link #setResourceLoader} in order
* for the given MetadataReaderFactory to override the default factory.
*/
public void setMetadataReaderFactory(MetadataReaderFactory metadataReaderFactory) {
this.metadataReaderFactory = metadataReaderFactory;
}
/**
* Return the MetadataReaderFactory used by this component provider.
*/
public final MetadataReaderFactory getMetadataReaderFactory() {
if (this.metadataReaderFactory == null) {
this.metadataReaderFactory = new CachingMetadataReaderFactory();
}
return this.metadataReaderFactory;
}
/**
* Scan the class path for candidate components.
* @param basePackage the package to check for annotated classes
* @return a corresponding Set of autodetected bean definitions
*/
public Set The default implementation resolves placeholders against system properties,
* and converts a "."-based package path to a "/"-based resource path.
* @param basePackage the base package as specified by the user
* @return the pattern specification to be used for package searching
*/
protected String resolveBasePackage(String basePackage) {
return ClassUtils.convertClassNameToResourcePath(getEnvironment().resolveRequiredPlaceholders(basePackage));
}
/**
* Determine whether the given class does not match any exclude filter
* and does match at least one include filter.
* @param metadataReader the ASM ClassReader for the class
* @return whether the class qualifies as a candidate component
*/
protected boolean isCandidateComponent(MetadataReader metadataReader) throws IOException {
for (TypeFilter tf : this.excludeFilters) {
if (tf.match(metadataReader, getMetadataReaderFactory())) {
return false;
}
}
for (TypeFilter tf : this.includeFilters) {
if (tf.match(metadataReader, getMetadataReaderFactory())) {
return isConditionMatch(metadataReader);
}
}
return false;
}
/**
* Determine whether the given class is a candidate component based on any
* {@code @Conditional} annotations.
* @param metadataReader the ASM ClassReader for the class
* @return whether the class qualifies as a candidate component
*/
private boolean isConditionMatch(MetadataReader metadataReader) {
if (this.conditionEvaluator == null) {
this.conditionEvaluator =
new ConditionEvaluator(getRegistry(), this.environment, this.resourcePatternResolver);
}
return !this.conditionEvaluator.shouldSkip(metadataReader.getAnnotationMetadata());
}
/**
* Determine whether the given bean definition qualifies as candidate.
* The default implementation checks whether the class is not an interface
* and not dependent on an enclosing class.
* Can be overridden in subclasses.
* @param beanDefinition the bean definition to check
* @return whether the bean definition qualifies as a candidate component
*/
protected boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
AnnotationMetadata metadata = beanDefinition.getMetadata();
return (metadata.isIndependent() && (metadata.isConcrete() ||
(metadata.isAbstract() && metadata.hasAnnotatedMethods(Lookup.class.getName()))));
}
/**
* Clear the local metadata cache, if any, removing all cached class metadata.
*/
public void clearCache() {
if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
// Clear cache in externally provided MetadataReaderFactory; this is a no-op
// for a shared cache since it'll be cleared by the ApplicationContext.
((CachingMetadataReaderFactory) this.metadataReaderFactory).clearCache();
}
}
}