WebServerFactoryCustomizerBeanPostProcessor.java

/*
 * Copyright 2012-2017 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.web.server;

import java.util.ArrayList;
import java.util.Collection;
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.ListableBeanFactory;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.core.ResolvableType;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.util.Assert;

/**
 * {@link BeanPostProcessor} that applies all {@link WebServerFactoryCustomizer} beans
 * from the bean factory to {@link WebServerFactory} beans.
 *
 * @author Dave Syer
 * @author Phillip Webb
 * @author Stephane Nicoll
 * @since 2.0.0
 */
public class WebServerFactoryCustomizerBeanPostProcessor
		implements BeanPostProcessor, BeanFactoryAware {

	private ListableBeanFactory beanFactory;

	private List<WebServerFactoryCustomizer<?>> customizers;

	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		Assert.isInstanceOf(ListableBeanFactory.class, beanFactory,
				"WebServerCustomizerBeanPostProcessor can only be used "
						+ "with a ListableBeanFactory");
		this.beanFactory = (ListableBeanFactory) beanFactory;
	}

	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName)
			throws BeansException {
		if (bean instanceof WebServerFactory) {
			postProcessBeforeInitialization((WebServerFactory) bean);
		}
		return bean;
	}

	@Override
	public Object postProcessAfterInitialization(Object bean, String beanName)
			throws BeansException {
		return bean;
	}

	private void postProcessBeforeInitialization(WebServerFactory bean) {
		for (WebServerFactoryCustomizer<?> customizer : getCustomizers()) {
			Class<?> type = ResolvableType
					.forClass(WebServerFactoryCustomizer.class, customizer.getClass())
					.getGeneric().resolve(WebServerFactory.class);
			if (type.isInstance(bean)) {
				invokeCustomizer(customizer, bean);
			}
		}
	}

	@SuppressWarnings({ "rawtypes", "unchecked" })
	private void invokeCustomizer(WebServerFactoryCustomizer customizer,
			WebServerFactory webServerFactory) {
		try {
			customizer.customize(webServerFactory);
		}
		catch (ClassCastException ex) {
			String msg = ex.getMessage();
			if (msg == null || msg.startsWith(webServerFactory.getClass().getName())) {
				// Possibly a lambda-defined listener which we could not resolve the
				// generic event type for
				logLambdaDebug(customizer, ex);
			}
			else {
				throw ex;
			}
		}
	}

	private void logLambdaDebug(WebServerFactoryCustomizer<?> customizer,
			ClassCastException ex) {
		Log logger = LogFactory.getLog(getClass());
		if (logger.isDebugEnabled()) {
			logger.debug("Non-matching factory type for customizer: " + customizer, ex);
		}
	}

	private Collection<WebServerFactoryCustomizer<?>> getCustomizers() {
		if (this.customizers == null) {
			// Look up does not include the parent context
			this.customizers = new ArrayList<>(getWebServerFactoryCustomizerBeans());
			Collections.sort(this.customizers, AnnotationAwareOrderComparator.INSTANCE);
			this.customizers = Collections.unmodifiableList(this.customizers);
		}
		return this.customizers;
	}

	@SuppressWarnings({ "unchecked", "rawtypes" })
	private Collection<WebServerFactoryCustomizer<?>> getWebServerFactoryCustomizerBeans() {
		return (Collection) this.beanFactory
				.getBeansOfType(WebServerFactoryCustomizer.class, false, false).values();
	}

}