org.springframework.boot.autoconfigure.ComponentScanDetector.java Source code

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Here is the source code for org.springframework.boot.autoconfigure.ComponentScanDetector.java

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/*
 * Copyright 2012-2013 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.boot.autoconfigure;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.annotation.AnnotationAttributes;
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.core.type.classreading.SimpleMetadataReaderFactory;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;

/**
 * Helper to detect a component scan declared in the enclosing context (normally on a
 * {@code @Configuration} class). Once the component scan is detected, the base packages
 * are stored for retrieval later.
 * 
 * @author Dave Syer
 * @author Phillip Webb
 * @see AutoConfigurationUtils
 */
public class ComponentScanDetector implements ImportBeanDefinitionRegistrar, BeanFactoryAware {

    private final Log logger = LogFactory.getLog(getClass());

    private BeanFactory beanFactory;

    private MetadataReaderFactory metadataReaderFactory = new SimpleMetadataReaderFactory();

    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata,
            final BeanDefinitionRegistry registry) {
        storeComponentScanBasePackages();
    }

    private void storeComponentScanBasePackages() {
        if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
            storeComponentScanBasePackages((ConfigurableListableBeanFactory) this.beanFactory);
        } else {
            if (this.logger.isWarnEnabled()) {
                this.logger.warn("Unable to read @ComponentScan annotations for auto-configure");
            }
        }
    }

    private void storeComponentScanBasePackages(ConfigurableListableBeanFactory beanFactory) {
        List<String> basePackages = new ArrayList<String>();
        for (String beanName : beanFactory.getBeanDefinitionNames()) {
            BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
            String[] basePackagesAttribute = (String[]) beanDefinition.getAttribute("componentScanBasePackages");
            if (basePackagesAttribute != null) {
                basePackages.addAll(Arrays.asList(basePackagesAttribute));
            }
            AnnotationMetadata metadata = getMetadata(beanDefinition);
            basePackages.addAll(getBasePackages(metadata));
        }
        AutoConfigurationUtils.storeBasePackages(beanFactory, basePackages);
    }

    private AnnotationMetadata getMetadata(BeanDefinition beanDefinition) {
        if (beanDefinition instanceof AbstractBeanDefinition
                && ((AbstractBeanDefinition) beanDefinition).hasBeanClass()) {
            Class<?> beanClass = ((AbstractBeanDefinition) beanDefinition).getBeanClass();
            if (Enhancer.isEnhanced(beanClass)) {
                beanClass = beanClass.getSuperclass();
            }
            return new StandardAnnotationMetadata(beanClass, true);
        }
        String className = beanDefinition.getBeanClassName();
        if (className != null) {
            try {
                MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(className);
                return metadataReader.getAnnotationMetadata();
            } catch (IOException ex) {
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug(
                            "Could not find class file for introspecting @ComponentScan classes: " + className, ex);
                }
            }
        }
        return null;
    }

    private List<String> getBasePackages(AnnotationMetadata metadata) {
        AnnotationAttributes attributes = AnnotationAttributes.fromMap(
                (metadata == null ? null : metadata.getAnnotationAttributes(ComponentScan.class.getName(), true)));
        if (attributes != null) {
            List<String> basePackages = new ArrayList<String>();
            addAllHavingText(basePackages, attributes.getStringArray("value"));
            addAllHavingText(basePackages, attributes.getStringArray("basePackages"));
            for (String packageClass : attributes.getStringArray("basePackageClasses")) {
                basePackages.add(ClassUtils.getPackageName(packageClass));
            }
            if (basePackages.isEmpty()) {
                basePackages.add(ClassUtils.getPackageName(metadata.getClassName()));
            }
            return basePackages;
        }
        return Collections.emptyList();
    }

    private void addAllHavingText(List<String> list, String[] strings) {
        for (String s : strings) {
            if (StringUtils.hasText(s)) {
                list.add(s);
            }
        }
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory = beanFactory;
    }
}