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

Introduction

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

Source

/*
 * 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.HashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.servlet.http.HttpServletRequest;

import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.stereotype.Controller;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping;

/**
 * @description: implementation of {@link HandlersRegistry} made by copy-paste from Spring MVC
 * usage: instantiate this bean in the root context, call registerXxx methods from nested children
 * contexts to register controllers and request handlers.
 * don't forget to instantiate HandlerAdapters beans and follow Spring MVC conventions.
 */
public class ContextParentAnnotationHandlerMapping extends DefaultAnnotationHandlerMapping
        implements HandlersRegistry {

    private final Map<Class<?>, RequestMapping> cachedMappings = new HashMap<Class<?>, RequestMapping>();

    /**
     * @see org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping.determineUrlsForHandler(String)
     */
    protected String[] determineUrlsForHandlerByName(String beanName) {
        List<String> urls = new ArrayList<String>();
        if (beanName.startsWith("/")) {
            urls.add(beanName);
        }
        /* does nothing due to lack of
           * String[] aliases = getApplicationContext().getAliases(beanName);
          for (int i = 0; i < aliases.length; i++) {
          if (aliases[i].startsWith("/")) {
              urls.add(aliases[i]);
          }
          }*/
        return StringUtils.toStringArray(urls);
    }

    public Void registerByName(String url, Object controller) {
        String[] urls = determineUrlsForHandlerByName(url);
        register(urls, controller);
        return null;
    }

    private void register(String[] urls, Object handler) {
        if (!ObjectUtils.isEmpty(urls)) {
            // URL paths found: Let's consider it a handler.
            Assert.notNull(urls, "URL path array must not be null");
            for (int j = 0; j < urls.length; j++) {
                registerHandler(urls[j], handler);
            }
        } else {
            if (logger.isDebugEnabled()) {
                logger.debug("Rejected bean '" + handler + "': no URL paths identified");
            }
        }
    }

    public Void registerByAnnotation(Object handler) {
        register(determineUrlsByAnnotations(handler), handler);
        return null;
    }

    protected String[] determineUrlsByAnnotations(Object handler) {
        Class<? extends Object> handlerType = handler.getClass();
        RequestMapping mapping = AnnotationUtils.findAnnotation(handlerType, RequestMapping.class);

        if (mapping != null) {
            // @RequestMapping found at type level
            this.cachedMappings.put(handlerType, mapping);
            Set<String> urls = new LinkedHashSet<String>();
            String[] paths = mapping.value();
            if (paths.length > 0) {
                // @RequestMapping specifies paths at type level
                for (String path : paths) {
                    addUrlsForPath(urls, path);
                }
                return StringUtils.toStringArray(urls);
            } else {
                // actual paths specified by @RequestMapping at method level
                return determineUrlsForHandlerMethods(handlerType);
            }
        } else if (AnnotationUtils.findAnnotation(handlerType, Controller.class) != null) {
            // @RequestMapping to be introspected at method level
            return determineUrlsForHandlerMethods(handlerType);
        } else {
            return null;
        }
    }

    protected void validateHandler(Object handler, HttpServletRequest request) throws Exception {
        RequestMapping mapping = this.cachedMappings.get(handler.getClass());
        if (mapping == null) {
            mapping = AnnotationUtils.findAnnotation(handler.getClass(), RequestMapping.class);
        }
        if (mapping != null) {
            validateMapping(mapping, request);
        }
    }
}