org.springframework.aop.framework.autoproxy.AutoProxyUtils.java Source code

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Here is the source code for org.springframework.aop.framework.autoproxy.AutoProxyUtils.java

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/*
 * 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.aop.framework.autoproxy;

import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.core.Conventions;
import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;

/**
 * Utilities for auto-proxy aware components.
 * Mainly for internal use within the framework.
 *
 * @author Juergen Hoeller
 * @since 2.0.3
 * @see AbstractAutoProxyCreator
 */
public abstract class AutoProxyUtils {

    /**
     * Bean definition attribute that may indicate whether a given bean is supposed
     * to be proxied with its target class (in case of it getting proxied in the first
     * place). The value is {@code Boolean.TRUE} or {@code Boolean.FALSE}.
     * <p>Proxy factories can set this attribute if they built a target class proxy
     * for a specific bean, and want to enforce that bean can always be cast
     * to its target class (even if AOP advices get applied through auto-proxying).
     * @see #shouldProxyTargetClass
     */
    public static final String PRESERVE_TARGET_CLASS_ATTRIBUTE = Conventions
            .getQualifiedAttributeName(AutoProxyUtils.class, "preserveTargetClass");

    /**
     * Bean definition attribute that indicates the original target class of an
     * auto-proxied bean, e.g. to be used for the introspection of annotations
     * on the target class behind an interface-based proxy.
     * @since 4.2.3
     * @see #determineTargetClass
     */
    public static final String ORIGINAL_TARGET_CLASS_ATTRIBUTE = Conventions
            .getQualifiedAttributeName(AutoProxyUtils.class, "originalTargetClass");

    /**
     * Determine whether the given bean should be proxied with its target
     * class rather than its interfaces. Checks the
     * {@link #PRESERVE_TARGET_CLASS_ATTRIBUTE "preserveTargetClass" attribute}
     * of the corresponding bean definition.
     * @param beanFactory the containing ConfigurableListableBeanFactory
     * @param beanName the name of the bean
     * @return whether the given bean should be proxied with its target class
     */
    public static boolean shouldProxyTargetClass(ConfigurableListableBeanFactory beanFactory,
            @Nullable String beanName) {

        if (beanName != null && beanFactory.containsBeanDefinition(beanName)) {
            BeanDefinition bd = beanFactory.getBeanDefinition(beanName);
            return Boolean.TRUE.equals(bd.getAttribute(PRESERVE_TARGET_CLASS_ATTRIBUTE));
        }
        return false;
    }

    /**
     * Determine the original target class for the specified bean, if possible,
     * otherwise falling back to a regular {@code getType} lookup.
     * @param beanFactory the containing ConfigurableListableBeanFactory
     * @param beanName the name of the bean
     * @return the original target class as stored in the bean definition, if any
     * @since 4.2.3
     * @see org.springframework.beans.factory.BeanFactory#getType(String)
     */
    @Nullable
    public static Class<?> determineTargetClass(ConfigurableListableBeanFactory beanFactory,
            @Nullable String beanName) {

        if (beanName == null) {
            return null;
        }
        if (beanFactory.containsBeanDefinition(beanName)) {
            BeanDefinition bd = beanFactory.getMergedBeanDefinition(beanName);
            Class<?> targetClass = (Class<?>) bd.getAttribute(ORIGINAL_TARGET_CLASS_ATTRIBUTE);
            if (targetClass != null) {
                return targetClass;
            }
        }
        return beanFactory.getType(beanName);
    }

    /**
     * Expose the given target class for the specified bean, if possible.
     * @param beanFactory the containing ConfigurableListableBeanFactory
     * @param beanName the name of the bean
     * @param targetClass the corresponding target class
     * @since 4.2.3
     */
    static void exposeTargetClass(ConfigurableListableBeanFactory beanFactory, @Nullable String beanName,
            Class<?> targetClass) {

        if (beanName != null && beanFactory.containsBeanDefinition(beanName)) {
            beanFactory.getMergedBeanDefinition(beanName).setAttribute(ORIGINAL_TARGET_CLASS_ATTRIBUTE,
                    targetClass);
        }
    }

    /**
     * Determine whether the given bean name indicates an "original instance"
     * according to {@link AutowireCapableBeanFactory#ORIGINAL_INSTANCE_SUFFIX},
     * skipping any proxy attempts for it.
     * @param beanName the name of the bean
     * @param beanClass the corresponding bean class
     * @since 5.1
     * @see AutowireCapableBeanFactory#ORIGINAL_INSTANCE_SUFFIX
     */
    static boolean isOriginalInstance(String beanName, Class<?> beanClass) {
        if (!StringUtils.hasLength(beanName) || beanName.length() != beanClass.getName().length()
                + AutowireCapableBeanFactory.ORIGINAL_INSTANCE_SUFFIX.length()) {
            return false;
        }
        return (beanName.startsWith(beanClass.getName())
                && beanName.endsWith(AutowireCapableBeanFactory.ORIGINAL_INSTANCE_SUFFIX));
    }

}