com.excilys.ebi.bank.web.interceptor.AnnotatedMethodHandlerInterceptor.java Source code

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Here is the source code for com.excilys.ebi.bank.web.interceptor.AnnotatedMethodHandlerInterceptor.java

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/**
 * Copyright 2011-2012 eBusiness Information, Groupe Excilys (www.excilys.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.excilys.ebi.bank.web.interceptor;

import java.lang.annotation.Annotation;
import java.util.Map;

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

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ui.ModelMap;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.view.RedirectView;

import com.excilys.ebi.bank.service.AnnotationScanner;

public class AnnotatedMethodHandlerInterceptor<A extends Annotation> implements HandlerInterceptor {

    private final Class<A> annotationType;

    @Autowired
    private AnnotationScanner annotationScanner;

    public AnnotatedMethodHandlerInterceptor(Class<A> annotationType) {
        this.annotationType = annotationType;
    }

    protected A getAnnotation(HandlerMethod handlerMethod) {
        return annotationScanner.getMethodOrTypeAnnotation(annotationType, handlerMethod.getMethod(),
                handlerMethod.getBeanType());
    }

    private boolean shouldIntercept(HandlerMethod handlerMethod) {
        return getAnnotation(handlerMethod) != null;
    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {

        if (handler instanceof HandlerMethod) {
            HandlerMethod handlerMethod = HandlerMethod.class.cast(handler);
            if (shouldIntercept(handlerMethod)) {
                return preHandleInternal(request, response, handlerMethod);
            }
        }
        return true;
    }

    protected boolean preHandleInternal(HttpServletRequest request, HttpServletResponse response,
            HandlerMethod handlerMethod) throws Exception {
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {

        if (modelAndView != null && !isRedirect(modelAndView) && handler instanceof HandlerMethod) {
            HandlerMethod handlerMethod = HandlerMethod.class.cast(handler);
            if (shouldIntercept(handlerMethod)) {

                @SuppressWarnings({ "rawtypes", "unchecked" })
                Map<String, ?> pathVariables = (Map) request.getAttribute(View.PATH_VARIABLES);
                postHandleInternal(request, response, handlerMethod, modelAndView, pathVariables);
            }
        }
    }

    private boolean isRedirect(ModelAndView modelAndView) {
        return modelAndView.getView() instanceof RedirectView
                || (modelAndView.getViewName() != null && modelAndView.getViewName().startsWith("redirect:"));
    }

    protected void postHandleInternal(HttpServletRequest request, HttpServletResponse response,
            HandlerMethod handlerMethod, ModelAndView modelAndView, Map<String, ?> pathVariables) throws Exception {
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
            Exception ex) throws Exception {

        if (handler instanceof HandlerMethod) {
            HandlerMethod handlerMethod = HandlerMethod.class.cast(handler);
            if (shouldIntercept(handlerMethod)) {
                afterCompletionInternal(request, response, handlerMethod, ex);
            }
        }
    }

    public void afterCompletionInternal(HttpServletRequest request, HttpServletResponse response,
            HandlerMethod handlerMethod, Exception ex) throws Exception {
    }

    @SuppressWarnings("unchecked")
    protected <T> T getModelOrPathAttribute(String name, ModelMap model, Map<String, ?> pathVariables) {
        T value = (T) model.get(name);
        if (value == null && pathVariables != null) {
            value = (T) pathVariables.get(name);
        }
        return value;
    }
}