org.springframework.data.util.AnnotatedTypeScanner.java Source code

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Here is the source code for org.springframework.data.util.AnnotatedTypeScanner.java

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/*
 * Copyright 2014-2019 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
 *
 *      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.util;

import java.lang.annotation.Annotation;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
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.io.ResourceLoader;
import org.springframework.core.type.filter.AnnotationTypeFilter;
import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;

/**
 * Scanner to find types with annotations on the classpath.
 *
 * @author Oliver Gierke
 * @author Christoph Strobl
 */
public class AnnotatedTypeScanner implements ResourceLoaderAware, EnvironmentAware {

    private final Iterable<Class<? extends Annotation>> annotationTypess;
    private final boolean considerInterfaces;

    private @Nullable ResourceLoader resourceLoader;
    private @Nullable Environment environment;

    /**
     * Creates a new {@link AnnotatedTypeScanner} for the given annotation types.
     *
     * @param annotationTypes the annotation types to scan for.
     */
    @SafeVarargs
    public AnnotatedTypeScanner(Class<? extends Annotation>... annotationTypes) {
        this(true, annotationTypes);
    }

    /**
     * Creates a new {@link AnnotatedTypeScanner} for the given annotation types.
     *
     * @param considerInterfaces whether to consider interfaces as well.
     * @param annotationTypes the annotations to scan for.
     */
    @SafeVarargs
    public AnnotatedTypeScanner(boolean considerInterfaces, Class<? extends Annotation>... annotationTypes) {

        this.annotationTypess = Arrays.asList(annotationTypes);
        this.considerInterfaces = considerInterfaces;
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.context.ResourceLoaderAware#setResourceLoader(org.springframework.core.io.ResourceLoader)
     */
    @Override
    public void setResourceLoader(ResourceLoader resourceLoader) {
        this.resourceLoader = resourceLoader;
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.context.EnvironmentAware#setEnvironment(org.springframework.core.env.Environment)
     */
    @Override
    public void setEnvironment(Environment environment) {
        this.environment = environment;
    }

    public Set<Class<?>> findTypes(String... basePackages) {
        return findTypes(Arrays.asList(basePackages));
    }

    public Set<Class<?>> findTypes(Iterable<String> basePackages) {

        ClassPathScanningCandidateComponentProvider provider = new InterfaceAwareScanner(considerInterfaces);

        if (resourceLoader != null) {
            provider.setResourceLoader(resourceLoader);
        }

        if (environment != null) {
            provider.setEnvironment(environment);
        }

        for (Class<? extends Annotation> annotationType : annotationTypess) {
            provider.addIncludeFilter(new AnnotationTypeFilter(annotationType, true, considerInterfaces));
        }

        Set<Class<?>> types = new HashSet<>();

        ResourceLoader loader = resourceLoader;
        ClassLoader classLoader = loader == null ? null : loader.getClassLoader();

        for (String basePackage : basePackages) {

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

                String beanClassName = definition.getBeanClassName();

                if (beanClassName == null) {
                    throw new IllegalStateException(
                            String.format("Unable to obtain bean class name from bean definition %s!", definition));
                }

                try {
                    types.add(ClassUtils.forName(beanClassName, classLoader));
                } catch (ClassNotFoundException o_O) {
                    throw new IllegalStateException(o_O);
                }
            }
        }

        return types;
    }

    /**
     * Custom extension of {@link ClassPathScanningCandidateComponentProvider} to make sure interfaces to not get dropped
     * from scanning results.
     *
     * @author Oliver Gierke
     */
    private static class InterfaceAwareScanner extends ClassPathScanningCandidateComponentProvider {

        private final boolean considerInterfaces;

        public InterfaceAwareScanner(boolean considerInterfaces) {
            super(false);
            this.considerInterfaces = considerInterfaces;
        }

        /*
         * (non-Javadoc)
         * @see org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider#isCandidateComponent(org.springframework.beans.factory.annotation.AnnotatedBeanDefinition)
         */
        @Override
        protected boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
            return super.isCandidateComponent(beanDefinition)
                    || considerInterfaces && beanDefinition.getMetadata().isInterface();
        }
    }
}