net.danielkvasnicka.flower.FlowerDispatcherServlet.java Source code

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Here is the source code for net.danielkvasnicka.flower.FlowerDispatcherServlet.java

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/*
FLOWER framework for Spring -- expose your Spring beans through HTTP -- http://code.google.com/p/spring-flower/
Copyright (C) 2009 Daniel Kvasni?ka jr.
    
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
    
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.
    
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

package net.danielkvasnicka.flower;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Map;

import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import net.danielkvasnicka.flower.beans.WebAccessibleBean;
import net.danielkvasnicka.flower.core.Constants;
import net.danielkvasnicka.flower.core.UrlMappingHolder;
import net.danielkvasnicka.flower.core.WebAccessibleBeanMetadata;
import net.danielkvasnicka.flower.core.api.WebAccessibleBeanResolver;
import net.danielkvasnicka.flower.exception.FlowerRuntimeException;
import net.danielkvasnicka.flower.response.api.Response;

/**
 * This is the heart of Flower.
 * This servlet receives the URL, uses the resolver to get the bean metadata, loads
 * the bean, runs the appropriate method and then sends the response.
 * 
 * @author Daniel Kvasnicka jr.
 */
public class FlowerDispatcherServlet implements Servlet {

    /**
     * Spring app ctx.
     */
    private ApplicationContext appCtx;

    /**
     * Servlet config reference
     */
    private ServletConfig servletConfig;

    /**
     * The resolver used to get the bean metadata
     */
    @Autowired
    private WebAccessibleBeanResolver webAccessibleBeanResolver;

    /**
     * @see Servlet#destroy()
     */
    @Override
    public void destroy() {

    }

    /**
     * @see Servlet#service(ServletRequest, ServletResponse)
     */
    @Override
    public void service(final ServletRequest request, final ServletResponse response)
            throws ServletException, IOException {

        // get the URL mapping bean
        final UrlMappingHolder urlMappingHolder = (UrlMappingHolder) this.appCtx
                .getBean(Constants.URL_MAPPING_HOLDER_BEAN_NAME);

        final HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        final HttpServletResponse httpServletResponse = (HttpServletResponse) response;

        // get the mapping
        final Map<String, String> urlMapping = urlMappingHolder.getUrlMapping();

        // get the current url and use it together with the mapping to retreive the bean metadata
        final String url = httpServletRequest.getRequestURI()
                .substring(httpServletRequest.getContextPath().length());
        final WebAccessibleBeanMetadata beanMetadata = this.webAccessibleBeanResolver.resolve(urlMapping, url);

        // no bean has been found for this URL
        if (beanMetadata == null) {
            httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND,
                    "No web accessible bean has been found for this URL.");
            return;
        }

        // we get the bean and inject the params
        final WebAccessibleBean bean = (WebAccessibleBean) this.appCtx.getBean(beanMetadata.name);
        bean.setParameters(beanMetadata.parameters);

        // we add GET/POST params, which OVERWRITES the REST params
        for (final Object key : httpServletRequest.getParameterMap().keySet()) {
            bean.getParameters().put(key.toString(), httpServletRequest.getParameter(key.toString()));
        }

        // we run the desired method and send the response
        try {
            final Method method = bean.getClass().getMethod(beanMetadata.methodName);
            final Response beanResponse = (Response) method.invoke(bean);
            beanResponse.send(httpServletRequest, httpServletResponse);

        } catch (SecurityException e) {
            throw new FlowerRuntimeException(e);
        } catch (NoSuchMethodException e) {
            httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND,
                    "Method '" + beanMetadata.methodName + "' not found on " + bean.getClass().getName());
            return;
        } catch (IllegalArgumentException e) {
            throw new FlowerRuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new FlowerRuntimeException(e);
        } catch (InvocationTargetException e) {
            throw new FlowerRuntimeException(e);
        }
    }

    /**
     * @param webAccessibleBeanResolver the webAccessibleBeanResolver to set
     */
    public void setWebAccessibleBeanResolver(WebAccessibleBeanResolver webAccessibleBeanResolver) {
        this.webAccessibleBeanResolver = webAccessibleBeanResolver;
    }

    @Override
    public ServletConfig getServletConfig() {
        return this.servletConfig;
    }

    @Override
    public String getServletInfo() {
        return "Flower dispatcher servlet";
    }

    /**
     * Setup Spring managed resources on me
     */
    @Override
    public void init(final ServletConfig servletConfig) throws ServletException {
        this.servletConfig = servletConfig;
        this.appCtx = WebApplicationContextUtils.getWebApplicationContext(servletConfig.getServletContext());
        this.appCtx.getAutowireCapableBeanFactory().autowireBeanProperties(this,
                AutowireCapableBeanFactory.AUTOWIRE_BY_NAME, true);
    }
}