Backport streamlined ClassPathBeanDefinitionScanner setup

Issue: SPR-15061

Author: jhoeller

spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigApplicationContext.java

@@ -35,7 +35,7 @@
  * deliberately override certain bean definitions via an extra {@code @Configuration}
  * class.
  *
- * <p>See @{@link Configuration} Javadoc for usage examples.
+ * <p>See @{@link Configuration}'s javadoc for usage examples.
  *
  * @author Chris Beams
  * @author Juergen Hoeller

spring-context/src/main/java/org/springframework/context/annotation/ClassPathBeanDefinitionScanner.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -132,16 +132,39 @@ public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean u
 	 * @since 3.1
 	 * @see #setResourceLoader
 	 */
-	public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters, Environment environment) {
-		super(useDefaultFilters, environment);
+	public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters,
+			Environment environment) {
+
+		this(registry, useDefaultFilters, environment,
+				(registry instanceof ResourceLoader ? (ResourceLoader) registry : null));
+	}
+
+	/**
+	 * Create a new {@code ClassPathBeanDefinitionScanner} for the given bean factory and
+	 * using the given {@link Environment} when evaluating bean definition profile metadata.
+	 * @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
+	 * @param resourceLoader the {@link ResourceLoader} to use
+	 * @since 4.3.6
+	 */
+	public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters,
+			Environment environment, ResourceLoader resourceLoader) {
 
 		Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
 		this.registry = registry;
 
-		// Determine ResourceLoader to use.
-		if (this.registry instanceof ResourceLoader) {
-			setResourceLoader((ResourceLoader) this.registry);
+		if (useDefaultFilters) {
+			registerDefaultFilters();
 		}
+		setEnvironment(environment);
+		setResourceLoader(resourceLoader);
 	}
 
 
@@ -192,7 +215,8 @@ public void setBeanNameGenerator(BeanNameGenerator beanNameGenerator) {
 	 * @see #setScopedProxyMode
 	 */
 	public void setScopeMetadataResolver(ScopeMetadataResolver scopeMetadataResolver) {
-		this.scopeMetadataResolver = (scopeMetadataResolver != null ? scopeMetadataResolver : new AnnotationScopeMetadataResolver());
+		this.scopeMetadataResolver =
+				(scopeMetadataResolver != null ? scopeMetadataResolver : new AnnotationScopeMetadataResolver());
 	}
 
 	/**
@@ -258,7 +282,8 @@ protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
 				}
 				if (checkCandidate(beanName, candidate)) {
 					BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
-					definitionHolder = AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
+					definitionHolder =
+							AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
 					beanDefinitions.add(definitionHolder);
 					registerBeanDefinition(definitionHolder, this.registry);
 				}

spring-context/src/main/java/org/springframework/context/annotation/ClassPathScanningCandidateComponentProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -36,7 +36,6 @@
 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.classreading.CachingMetadataReaderFactory;
@@ -72,23 +71,30 @@ public class ClassPathScanningCandidateComponentProvider implements EnvironmentC
 
 	static final String DEFAULT_RESOURCE_PATTERN = "**/*.class";
 
-	protected final Log logger = LogFactory.getLog(getClass());
-
-	private Environment environment;
 
-	private ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
-
-	private MetadataReaderFactory metadataReaderFactory =
-			new CachingMetadataReaderFactory(this.resourcePatternResolver);
+	protected final Log logger = LogFactory.getLog(getClass());
 
 	private String resourcePattern = DEFAULT_RESOURCE_PATTERN;
 
 	private final List<TypeFilter> includeFilters = new LinkedList<TypeFilter>();
 
 	private final List<TypeFilter> excludeFilters = new LinkedList<TypeFilter>();
 
+	private Environment environment;
+
 	private ConditionEvaluator conditionEvaluator;
 
+	private ResourcePatternResolver resourcePatternResolver;
+
+	private MetadataReaderFactory metadataReaderFactory;
+
+
+	/**
+	 * Protected constructor for flexible subclass initialization.
+	 * @since 4.3.6
+	 */
+	protected ClassPathScanningCandidateComponentProvider() {
+	}
 
 	/**
 	 * Create a ClassPathScanningCandidateComponentProvider with a {@link StandardEnvironment}.
@@ -115,73 +121,10 @@ public ClassPathScanningCandidateComponentProvider(boolean useDefaultFilters, En
 		if (useDefaultFilters) {
 			registerDefaultFilters();
 		}
-		Assert.notNull(environment, "Environment must not be null");
-		this.environment = environment;
-	}
-
-
-	/**
-	 * Set the ResourceLoader to use for resource locations.
-	 * This will typically be a ResourcePatternResolver implementation.
-	 * <p>Default is PathMatchingResourcePatternResolver, also capable of
-	 * resource pattern resolving through the ResourcePatternResolver interface.
-	 * @see org.springframework.core.io.support.ResourcePatternResolver
-	 * @see org.springframework.core.io.support.PathMatchingResourcePatternResolver
-	 */
-	@Override
-	public void setResourceLoader(ResourceLoader resourceLoader) {
-		this.resourcePatternResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
-		this.metadataReaderFactory = new CachingMetadataReaderFactory(resourceLoader);
-	}
-
-	/**
-	 * Return the ResourceLoader that this component provider uses.
-	 */
-	public final ResourceLoader getResourceLoader() {
-		return this.resourcePatternResolver;
+		setEnvironment(environment);
+		setResourceLoader(null);
 	}
 
-	/**
-	 * Set the {@link MetadataReaderFactory} to use.
-	 * <p>Default is a {@link CachingMetadataReaderFactory} for the specified
-	 * {@linkplain #setResourceLoader resource loader}.
-	 * <p>Call this setter method <i>after</i> {@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() {
-		return this.metadataReaderFactory;
-	}
-
-	/**
-	 * Set the Environment to use when resolving placeholders and evaluating
-	 * {@link Conditional @Conditional}-annotated component classes.
-	 * <p>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() {
-		return this.environment;
-	}
-
-	/**
-	 * Returns the {@link BeanDefinitionRegistry} used by this scanner, if any.
-	 */
-	protected BeanDefinitionRegistry getRegistry() {
-		return null;
-	}
 
 	/**
 	 * Set the resource pattern to use when scanning the classpath.
@@ -256,6 +199,69 @@ protected void registerDefaultFilters() {
 		}
 	}
 
+	/**
+	 * Set the Environment to use when resolving placeholders and evaluating
+	 * {@link Conditional @Conditional}-annotated component classes.
+	 * <p>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() {
+		return this.environment;
+	}
+
+	/**
+	 * Return the {@link BeanDefinitionRegistry} used by this scanner, if any.
+	 */
+	protected BeanDefinitionRegistry getRegistry() {
+		return null;
+	}
+
+	/**
+	 * Set the {@link ResourceLoader} to use for resource locations.
+	 * This will typically be a {@link ResourcePatternResolver} implementation.
+	 * <p>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(ResourceLoader resourceLoader) {
+		this.resourcePatternResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
+		this.metadataReaderFactory = new CachingMetadataReaderFactory(resourceLoader);
+	}
+
+	/**
+	 * Return the ResourceLoader that this component provider uses.
+	 */
+	public final ResourceLoader getResourceLoader() {
+		return this.resourcePatternResolver;
+	}
+
+	/**
+	 * Set the {@link MetadataReaderFactory} to use.
+	 * <p>Default is a {@link CachingMetadataReaderFactory} for the specified
+	 * {@linkplain #setResourceLoader resource loader}.
+	 * <p>Call this setter method <i>after</i> {@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() {
+		return this.metadataReaderFactory;
+	}
+
 
 	/**
 	 * Scan the class path for candidate components.

spring-context/src/main/java/org/springframework/context/annotation/ComponentScanAnnotationParser.java

@@ -77,10 +77,8 @@ public Set<BeanDefinitionHolder> parse(AnnotationAttributes componentScan, final
 		Assert.state(this.environment != null, "Environment must not be null");
 		Assert.state(this.resourceLoader != null, "ResourceLoader must not be null");
 
-		ClassPathBeanDefinitionScanner scanner =
-				new ClassPathBeanDefinitionScanner(this.registry, componentScan.getBoolean("useDefaultFilters"));
-		scanner.setEnvironment(this.environment);
-		scanner.setResourceLoader(this.resourceLoader);
+		ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(this.registry,
+				componentScan.getBoolean("useDefaultFilters"), this.environment, this.resourceLoader);
 
 		Class<? extends BeanNameGenerator> generatorClass = componentScan.getClass("nameGenerator");
 		boolean useInheritedGenerator = (BeanNameGenerator.class == generatorClass);

spring-context/src/main/java/org/springframework/context/annotation/ComponentScanBeanDefinitionParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -98,8 +98,6 @@ protected ClassPathBeanDefinitionScanner configureScanner(ParserContext parserCo
 
 		// Delegate bean definition registration to scanner class.
 		ClassPathBeanDefinitionScanner scanner = createScanner(parserContext.getReaderContext(), useDefaultFilters);
-		scanner.setResourceLoader(parserContext.getReaderContext().getResourceLoader());
-		scanner.setEnvironment(parserContext.getReaderContext().getEnvironment());
 		scanner.setBeanDefinitionDefaults(parserContext.getDelegate().getBeanDefinitionDefaults());
 		scanner.setAutowireCandidatePatterns(parserContext.getDelegate().getAutowireCandidatePatterns());
 
@@ -127,7 +125,8 @@ protected ClassPathBeanDefinitionScanner configureScanner(ParserContext parserCo
 	}
 
 	protected ClassPathBeanDefinitionScanner createScanner(XmlReaderContext readerContext, boolean useDefaultFilters) {
-		return new ClassPathBeanDefinitionScanner(readerContext.getRegistry(), useDefaultFilters);
+		return new ClassPathBeanDefinitionScanner(readerContext.getRegistry(), useDefaultFilters,
+				readerContext.getEnvironment(), readerContext.getResourceLoader());
 	}
 
 	protected void registerComponents(
@@ -266,7 +265,7 @@ private Object instantiateUserDefinedStrategy(String className, Class<?> strateg
 			throw new IllegalArgumentException("Class [" + className + "] for strategy [" +
 					strategyType.getName() + "] not found", ex);
 		}
-		catch (Exception ex) {
+		catch (Throwable ex) {
 			throw new IllegalArgumentException("Unable to instantiate class [" + className + "] for strategy [" +
 					strategyType.getName() + "]: a zero-argument constructor is required", ex);
 		}

spring-core/src/main/java/org/springframework/core/type/classreading/CachingMetadataReaderFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -25,7 +25,7 @@
 
 /**
  * Caching implementation of the {@link MetadataReaderFactory} interface,
- * caching {@link MetadataReader} per Spring {@link Resource} handle
+ * caching a {@link MetadataReader} instance per Spring {@link Resource} handle
  * (i.e. per ".class" file).
  *
  * @author Juergen Hoeller
@@ -77,7 +77,7 @@ public CachingMetadataReaderFactory(ClassLoader classLoader) {
 
 	/**
 	 * Specify the maximum number of entries for the MetadataReader cache.
-	 * Default is 256.
+	 * <p>Default is 256.
 	 */
 	public void setCacheLimit(int cacheLimit) {
 		this.cacheLimit = cacheLimit;