shiro源码篇 - shiro的filter，你值得拥有

private void addServletContextInitializerBeans(ListableBeanFactory beanFactory) {
    for (Entry<String, ServletContextInitializer> initializerBean : getOrderedBeansOfType(
            beanFactory, ServletContextInitializer.class)) {
        addServletContextInitializerBean(initializerBean.getKey(),
                initializerBean.getValue(), beanFactory);
    }
}


private void addServletContextInitializerBean(String beanName,
        ServletContextInitializer initializer, ListableBeanFactory beanFactory) {
    if (initializer instanceof ServletRegistrationBean) {
        Servlet source = ((ServletRegistrationBean<?>) initializer).getServlet();
        addServletContextInitializerBean(Servlet.class, beanName, initializer,
                beanFactory, source);
    }
    else if (initializer instanceof FilterRegistrationBean) {
        Filter source = ((FilterRegistrationBean<?>) initializer).getFilter();
        addServletContextInitializerBean(Filter.class, beanName, initializer,
                beanFactory, source);
    }
    else if (initializer instanceof DelegatingFilterProxyRegistrationBean) {
        String source = ((DelegatingFilterProxyRegistrationBean) initializer)
                .getTargetBeanName();
        addServletContextInitializerBean(Filter.class, beanName, initializer,
                beanFactory, source);
    }
    else if (initializer instanceof ServletListenerRegistrationBean) {
        EventListener source = ((ServletListenerRegistrationBean<?>) initializer)
                .getListener();
        addServletContextInitializerBean(EventListener.class, beanName, initializer,
                beanFactory, source);
    }
    else {
        addServletContextInitializerBean(ServletContextInitializer.class, beanName,
                initializer, beanFactory, initializer);
    }
}

private void addAdaptableBeans(ListableBeanFactory beanFactory) {
    MultipartConfigElement multipartConfig = getMultipartConfig(beanFactory);
    addAsRegistrationBean(beanFactory, Servlet.class,
            new ServletRegistrationBeanAdapter(multipartConfig));
    addAsRegistrationBean(beanFactory, Filter.class,
            new FilterRegistrationBeanAdapter());
    for (Class<?> listenerType : ServletListenerRegistrationBean
            .getSupportedTypes()) {
        addAsRegistrationBean(beanFactory, EventListener.class,
                (Class<EventListener>) listenerType,
                new ServletListenerRegistrationBeanAdapter());
    }
}

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.shiro.web.servlet;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.*;
import java.io.IOException;
import java.util.List;

/**
 * A proxied filter chain is a {@link FilterChain} instance that proxies an original {@link FilterChain} as well
 * as a {@link List List} of other {@link Filter Filter}s that might need to execute prior to the final wrapped
 * original chain.  It allows a list of filters to execute before continuing the original (proxied)
 * {@code FilterChain} instance.
 *
 * @since 0.9
 */
public class ProxiedFilterChain implements FilterChain {

    //TODO - complete JavaDoc

    private static final Logger log = LoggerFactory.getLogger(ProxiedFilterChain.class);

    private FilterChain orig;                    // 原FilterChain，也就是servlet容器的FilterChain
    private List<Filter> filters;                // shiro默认的11个Filter
    private int index = 0;

    public ProxiedFilterChain(FilterChain orig, List<Filter> filters) {
        if (orig == null) {
            throw new NullPointerException("original FilterChain cannot be null.");
        }
        this.orig = orig;
        this.filters = filters;
        this.index = 0;
    }

    public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
        if (this.filters == null || this.filters.size() == this.index) {
            //we've reached the end of the wrapped chain, so invoke the original one:
            if (log.isTraceEnabled()) {
                log.trace("Invoking original filter chain.");
            }
            this.orig.doFilter(request, response);                        // 当shiro的11个Filter走完之后，继续走servlet容器的FilterChain
        } else {
            if (log.isTraceEnabled()) {
                log.trace("Invoking wrapped filter at index [" + this.index + "]");
            }
            this.filters.get(this.index++).doFilter(request, response, this);    // 递归逐个走shiro的11个Filter
        }
    }
}