com.griddynamics.banshun.web.ScanChildrenHandlerMapping.java Source code

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Here is the source code for com.griddynamics.banshun.web.ScanChildrenHandlerMapping.java

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/*
 * Copyright 2012 Grid Dynamics Consulting Services, Inc.
 *      http://www.griddynamics.com
 *
 * 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 com.griddynamics.banshun.web;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.griddynamics.banshun.ContextParentBean;
import com.griddynamics.banshun.Registry;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.context.*;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.core.OrderComparator;
import org.springframework.web.servlet.HandlerMapping;
import org.springframework.web.servlet.handler.AbstractUrlHandlerMapping;

public class ScanChildrenHandlerMapping extends ContextParentAnnotationHandlerMapping
        implements ApplicationListener<ApplicationEvent> {
    @SuppressWarnings("unused")
    private static final Logger log = LoggerFactory.getLogger(ContextParentBean.class);
    private static final Class<?>[] defaultHandlerMappingClasses = new Class[] {
            org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping.class,
            org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping.class };
    private Registry parentBean = null;

    public void setParentBean(Registry parentBean) {
        this.parentBean = parentBean;
    }

    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ContextRefreshedEvent) {
            scanChildContexts();
        }
    }

    public void scanChildContexts() {
        List<ConfigurableApplicationContext> children = ((ContextParentBean) parentBean).getChildren();
        for (ConfigurableApplicationContext child : children) {
            createHandlerMappingsAndRegisterHandlers(child);
        }
    }

    public void createHandlerMappingsAndRegisterHandlers(ApplicationContext child) {
        Map<String, HandlerMapping> matchingBeans = BeanFactoryUtils.beansOfTypeIncludingAncestors(child,
                HandlerMapping.class, true, false);

        List<HandlerMapping> handlerMappings = new ArrayList<HandlerMapping>(matchingBeans.values());
        OrderComparator.sort(handlerMappings);
        handlerMappings.remove(this);
        if (handlerMappings.isEmpty()) {
            handlerMappings = createDefaultHandlerMappings(child);
            if (logger.isDebugEnabled()) {
                logger.debug("No HandlerMappings found in context '" + child.getDisplayName() + "': using default");
            }
        }
        registerHandlers(handlerMappings);
    }

    private void registerHandlers(List<HandlerMapping> handlerMappings) {
        for (HandlerMapping mapping : handlerMappings) {
            AbstractUrlHandlerMapping abstractUrlHandlerMapping = (AbstractUrlHandlerMapping) mapping;
            Map<String, Object> handlerMap = abstractUrlHandlerMapping.getHandlerMap();
            for (String url : handlerMap.keySet()) {
                Object handler = handlerMap.get(url);
                registerHandler(url, handler);
            }
        }
    }

    private List<HandlerMapping> createDefaultHandlerMappings(ApplicationContext context) {
        List<HandlerMapping> handlerMappings = new ArrayList<HandlerMapping>(2);
        try {
            for (Class<?> clazz : defaultHandlerMappingClasses) {
                Object handlerMapping = context.getAutowireCapableBeanFactory().createBean(clazz);
                handlerMappings.add((HandlerMapping) handlerMapping);
            }
        } catch (Exception ex) {
            throw new BeanInitializationException(ex.getMessage(), ex);
        }

        return handlerMappings;
    }
}