spring-data-jpa ClasspathScanningPersistenceUnitPostProcessor 源码

spring-data-jpa ClasspathScanningPersistenceUnitPostProcessor 代码

文件路径：/spring-data-jpa/src/main/java/org/springframework/data/jpa/support/ClasspathScanningPersistenceUnitPostProcessor.java

/*
 * Copyright 2011-2022 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
 *
 *      https://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.data.jpa.support;

import java.io.IOException;
import java.net.URI;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import jakarta.persistence.Entity;
import jakarta.persistence.MappedSuperclass;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
import org.springframework.core.env.Environment;
import org.springframework.core.env.StandardEnvironment;
import org.springframework.core.io.DefaultResourceLoader;
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.filter.AnnotationTypeFilter;
import org.springframework.lang.Nullable;
import org.springframework.orm.jpa.persistenceunit.MutablePersistenceUnitInfo;
import org.springframework.orm.jpa.persistenceunit.PersistenceUnitPostProcessor;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * {@link PersistenceUnitPostProcessor} that will scan for classes annotated with {@link Entity} or
 * {@link MappedSuperclass} and add them to the {@link jakarta.persistence.PersistenceUnit} post processed. Beyond that
 * JPA XML mapping files can be scanned as well by configuring a file name pattern.
 *
 * @author Oliver Gierke
 * @author Thomas Darimont
 * @author Mark Paluch
 * @author David Madden
 */
public class ClasspathScanningPersistenceUnitPostProcessor
		implements PersistenceUnitPostProcessor, ResourceLoaderAware, EnvironmentAware {

	private static final Log LOG = LogFactory.getLog(ClasspathScanningPersistenceUnitPostProcessor.class);

	private final String basePackage;

	private ResourcePatternResolver mappingFileResolver = new PathMatchingResourcePatternResolver();
	private Environment environment = new StandardEnvironment();
	private ResourceLoader resourceLoader = new DefaultResourceLoader();
	private @Nullable String mappingFileNamePattern;

	/**
	 * Creates a new {@link ClasspathScanningPersistenceUnitPostProcessor} using the given base package as scan base.
	 *
	 * @param basePackage must not be {@literal null} or empty.
	 */
	public ClasspathScanningPersistenceUnitPostProcessor(String basePackage) {

		Assert.hasText(basePackage, "Base package must not be null or empty");

		this.basePackage = basePackage;
	}

	/**
	 * Configures the file name pattern JPA entity mapping files shall scanned from the classpath. Lookup will use the
	 * configured base package as root.
	 *
	 * @param mappingFilePattern must not be {@literal null} or empty.
	 */
	public void setMappingFileNamePattern(String mappingFilePattern) {

		Assert.hasText(mappingFilePattern, "Mapping file pattern must not be null or empty");

		this.mappingFileNamePattern = mappingFilePattern;
	}

	@Override
	public void setResourceLoader(ResourceLoader resourceLoader) {

		Assert.notNull(resourceLoader, "ResourceLoader must not be null");

		this.mappingFileResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
		this.resourceLoader = resourceLoader;
	}

	@Override
	public void setEnvironment(Environment environment) {

		Assert.notNull(environment, "Environment must not be null");

		this.environment = environment;
	}

	@Override
	public void postProcessPersistenceUnitInfo(MutablePersistenceUnitInfo pui) {

		ClassPathScanningCandidateComponentProvider provider = new ClassPathScanningCandidateComponentProvider(false);

		provider.setEnvironment(environment);
		provider.setResourceLoader(resourceLoader);
		provider.addIncludeFilter(new AnnotationTypeFilter(Entity.class));
		provider.addIncludeFilter(new AnnotationTypeFilter(MappedSuperclass.class));

		for (BeanDefinition definition : provider.findCandidateComponents(basePackage)) {

			LOG.debug(String.format("Registering classpath-scanned entity %s in persistence unit info", definition.getBeanClassName()));

			if (definition.getBeanClassName() != null) {
				pui.addManagedClassName(definition.getBeanClassName());
			}
		}

		for (String location : scanForMappingFileLocations()) {

			LOG.debug(String.format("Registering classpath-scanned entity mapping file %s in persistence unit info", location));

			pui.addMappingFileName(location);
		}
	}

	/**
	 * Scans the configured base package for files matching the configured mapping file name pattern. Will simply return
	 * an empty {@link Set} in case no {@link ResourceLoader} or mapping file name pattern was configured. Resulting paths
	 * are resource-loadable from the application classpath according to the JPA spec.
	 *
	 * @see jakarta.persistence.spi.PersistenceUnitInfo#getMappingFileNames()
	 * @return
	 */
	private Set<String> scanForMappingFileLocations() {

		if (!StringUtils.hasText(mappingFileNamePattern)) {
			return Collections.emptySet();
		}

		/*
		 * Note that we cannot use File.pathSeparator here since resourcePath uses a forward slash path ('/') separator
		 * being an URI, while basePackagePathComponent has system dependent separator (on windows it's the backslash separator).
		 *
		 * See DATAJPA-407.
		 */
		char slash = '/';
		String basePackagePathComponent = basePackage.replace('.', slash);
		String path = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + basePackagePathComponent + slash
				+ mappingFileNamePattern;
		Resource[] scannedResources;

		try {
			scannedResources = mappingFileResolver.getResources(path);
		} catch (IOException e) {
			throw new IllegalStateException(String.format("Cannot load mapping files from path %s", path), e);
		}

		Set<String> mappingFileUris = new HashSet<>();

		for (Resource resource : scannedResources) {

			try {

				String resourcePath = getResourcePath(resource.getURI());
				String resourcePathInClasspath = resourcePath.substring(resourcePath.indexOf(basePackagePathComponent));
				mappingFileUris.add(resourcePathInClasspath);

			} catch (IOException e) {
				throw new IllegalStateException(String.format("Couldn't get URI for %s", resource), e);
			}
		}

		return mappingFileUris;
	}

	/**
	 * Returns the path from the given {@link URI}. In case the given {@link URI} is opaque, e.g. beginning with jar:file,
	 * the path is extracted from URI by leaving out the protocol prefix, see DATAJPA-519.
	 *
	 * @param uri
	 * @return
	 */
	private static String getResourcePath(URI uri) throws IOException {

		if (uri.isOpaque()) {
			// e.g. jar:file:/foo/lib/somelib.jar!/com/acme/orm.xml
			String rawPath = uri.toString();

			if (rawPath != null) {

				int exclamationMarkIndex = rawPath.lastIndexOf('!');

				if (exclamationMarkIndex > -1) {

					// /com/acme/orm.xml
					return rawPath.substring(exclamationMarkIndex + 1);
				}
			}
		}

		return uri.getPath();
	}
}

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