package anni.tools;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 * 自制的mvc消息轉發類.
 * 使用反射而非xml配置，因為我懶啊。
 *
 * @author Lingo
 * @version 1.0
 * @since 2006-01-01 20:02
 */
public class ServiceServlet extends HttpServlet {
    /**
     * 持久化.
     */
    private static final long serialVersionUID = 1L;

    /**
     * 處理請求的action所在的包名.
     */
    private String packageName;

    /**
     * 從配置文件web.xml中取package-name.
     * 如果沒有設置，那么默認使用的是anni.tools包
     * 反射的時候，就從這個包里尋找所要使用到的類
     *
     * @author Lingo
     * @since 2006-01-01 20:03
     * @param config servlet配置
     * @throws ServletException servlet異常
     */
    public final void init(final ServletConfig config)
        throws ServletException {
        super.init(config);
        packageName = getInitParameter("package-name");

        if ((packageName == null) || packageName.equals("")) {
            packageName = "anni.tools.";
        } else {
            packageName += ".";
        }
    }

    /**
     * 處理post請求.
     * @param request 請求
     * @param response 響應
     * @throws ServletException servlet異常
     * @throws IOException io異常
     */
    protected final void doPost(final HttpServletRequest request,
        final HttpServletResponse response)
        throws ServletException, IOException {
        process(request, response);
    }

    /**
     * 處理get請求.
     * @param request 請求
     * @param response 響應
     * @throws ServletException servlet異常
     * @throws IOException io異常
     */
    protected final void doGet(final HttpServletRequest request,
        final HttpServletResponse response)
        throws ServletException, IOException {
        process(request, response);
    }

    /**
     * 轉發請求.
     *
     * @author Lingo
     * @since 2006-01-01 19:36
     * @param request 請求
     * @param response 響應
     * @throws ServletException servlet異常
     * @throws IOException io異常
     */
    protected final void process(final HttpServletRequest request,
        final HttpServletResponse response)
        throws ServletException, IOException {
        String method = request.getParameter("method");
        Log.info("method - " + method);

        Class clazz;
        Service service;
        String forward = null;
        RequestDispatcher dispatcher = null;

        try {
            clazz = Class.forName(packageName + method);
            service = (Service) clazz.newInstance();
            forward = service.service(request);

            dispatcher = request.getRequestDispatcher(forward);
            dispatcher.forward(request, response);
        } catch (Throwable ex) {
            ex.printStackTrace();
        }
    }
}