org.springframework.oxm.jaxb.ClassPathJaxb2TypeScanner.java Source code

Introduction

Here is the source code for org.springframework.oxm.jaxb.ClassPathJaxb2TypeScanner.java

Source

/*
 * Copyright 2002-2018 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.oxm.jaxb;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.annotation.XmlEnum;
import javax.xml.bind.annotation.XmlRegistry;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlSeeAlso;
import javax.xml.bind.annotation.XmlType;

import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
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.TypeFilter;
import org.springframework.lang.Nullable;
import org.springframework.oxm.UncategorizedMappingException;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * Helper class for {@link Jaxb2Marshaller} that scans given packages for classes marked with JAXB2 annotations.
 *
 * @author Arjen Poutsma
 * @author Juergen Hoeller
 * @author David Harrigan
 * @author Biju Kunjummen
 * @since 3.1.1
 * @see #scanPackages()
 */
class ClassPathJaxb2TypeScanner {

    private static final String RESOURCE_PATTERN = "/**/*.class";

    private static final TypeFilter[] JAXB2_TYPE_FILTERS = new TypeFilter[] {
            new AnnotationTypeFilter(XmlRootElement.class, false), new AnnotationTypeFilter(XmlType.class, false),
            new AnnotationTypeFilter(XmlSeeAlso.class, false), new AnnotationTypeFilter(XmlEnum.class, false),
            new AnnotationTypeFilter(XmlRegistry.class, false) };

    private final ResourcePatternResolver resourcePatternResolver;

    private final String[] packagesToScan;

    public ClassPathJaxb2TypeScanner(@Nullable ClassLoader classLoader, String... packagesToScan) {
        Assert.notEmpty(packagesToScan, "'packagesToScan' must not be empty");
        this.resourcePatternResolver = new PathMatchingResourcePatternResolver(classLoader);
        this.packagesToScan = packagesToScan;
    }

    /**
     * Scan the packages for classes marked with JAXB2 annotations.
     * @throws UncategorizedMappingException in case of errors
     */
    public Class<?>[] scanPackages() throws UncategorizedMappingException {
        try {
            List<Class<?>> jaxb2Classes = new ArrayList<>();
            for (String packageToScan : this.packagesToScan) {
                String pattern = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
                        + ClassUtils.convertClassNameToResourcePath(packageToScan) + RESOURCE_PATTERN;
                Resource[] resources = this.resourcePatternResolver.getResources(pattern);
                MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(
                        this.resourcePatternResolver);
                for (Resource resource : resources) {
                    MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(resource);
                    if (isJaxb2Class(metadataReader, metadataReaderFactory)) {
                        String className = metadataReader.getClassMetadata().getClassName();
                        Class<?> jaxb2AnnotatedClass = ClassUtils.forName(className,
                                this.resourcePatternResolver.getClassLoader());
                        jaxb2Classes.add(jaxb2AnnotatedClass);
                    }
                }
            }
            return ClassUtils.toClassArray(jaxb2Classes);
        } catch (IOException ex) {
            throw new UncategorizedMappingException("Failed to scan classpath for unlisted classes", ex);
        } catch (ClassNotFoundException ex) {
            throw new UncategorizedMappingException("Failed to load annotated classes from classpath", ex);
        }
    }

    protected boolean isJaxb2Class(MetadataReader reader, MetadataReaderFactory factory) throws IOException {
        for (TypeFilter filter : JAXB2_TYPE_FILTERS) {
            if (filter.match(reader, factory) && !reader.getClassMetadata().isInterface()) {
                return true;
            }
        }
        return false;
    }

}