org.springjutsu.validation.mvc.SuccessViewHandlerInterceptor.java Source code

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Here is the source code for org.springjutsu.validation.mvc.SuccessViewHandlerInterceptor.java

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/*
 * Copyright 2010-2013 Duplichien, Wicksell, Springjutsu.org
 *
 * 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.springjutsu.validation.mvc;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import org.springjutsu.validation.mvc.annotations.SuccessView;
import org.springjutsu.validation.mvc.annotations.SuccessViews;
import org.springjutsu.validation.util.RequestUtils;

/**
 * Handles the implementation of the @link{SuccessView} annotation.
 * Self-registering bean that places itself at the end of the interceptor
 * chain on a handler adapter.
 * @author Clark Duplichien
 *
 */
public class SuccessViewHandlerInterceptor extends HandlerInterceptorAdapter {

    /**
     * Responsible for redirecting to the view defined
     * in the @link{SuccessView} annotation on the current
     * handler method.
     * In the event that there are multiple possible 
     * success paths defined for the success view, 
     * will attempt to isolate the closest matching
     * url-path key and redirect to the value path,
     * as described in @link{SuccessView}
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) {

        if (!(handler instanceof HandlerMethod)) {
            return;
        }

        SuccessViews successViews = (SuccessViews) ((HandlerMethod) handler)
                .getMethodAnnotation(SuccessViews.class);
        SuccessView successView = (SuccessView) ((HandlerMethod) handler).getMethodAnnotation(SuccessView.class);
        String viewName = null;

        if (successView != null) {
            viewName = successView.value();
        } else if (successViews != null) {
            String[] controllerPaths = RequestUtils.getControllerRequestPaths((HandlerMethod) handler);
            viewName = findMatchingTargetUrl(successViews.value(), controllerPaths, request);
        }

        if (viewName == null) {
            return;
        }

        viewName = RequestUtils.replaceRestPathVariables(viewName, modelAndView.getModel(), request);
        modelAndView.setViewName(viewName);
    }

    /**
     * Given multiple possible view candidates, find the one whose sourceUrl
     * pattern best matches the current request url.
     * @param successViews An array of SuccessView candidate objects
     * @param controllerPaths RequestMapping mapped base paths for the controller
     * @param request The current request
     * @throws IllegalArgumentException if any SuccessView annotation does not
     * provide a sourceUrl value, or if multiple SuccessView annotations provide
     * the same sourceUrl value 
     * @return The view name mapped by the best matching SuccessView annotation
     */
    protected String findMatchingTargetUrl(SuccessView[] successViews, String[] controllerPaths,
            HttpServletRequest request) {
        Map<String, String> sourceTargetMap = new HashMap<String, String>();
        String[] sources = new String[successViews.length];
        for (int i = 0; i < successViews.length; i++) {
            SuccessView successView = successViews[i];

            if (successView.sourceUrl().isEmpty()) {
                throw new IllegalArgumentException(
                        "sourceUrl is required when specifying multiple success or failure views.");
            }

            if (sourceTargetMap.containsKey(successView.sourceUrl())) {
                throw new IllegalArgumentException(
                        "duplicate sourceUrl when specifying multiple success or failure views: "
                                + successView.sourceUrl());
            }

            sourceTargetMap.put(successView.sourceUrl(), successView.value());
            sources[i] = successView.sourceUrl();
        }

        String matchingSourceUrl = RequestUtils.findFirstMatchingRestPath(sources, controllerPaths, request);

        return matchingSourceUrl == null ? null : sourceTargetMap.get(matchingSourceUrl);
    }
}