och.comp.web.BaseErrorsServlet.java Source code

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Here is the source code for och.comp.web.BaseErrorsServlet.java

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/*
 * Copyright 2015 Evgeny Dolganov (evgenij.dolganov@gmail.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 och.comp.web;

import static och.util.Util.*;
import static och.util.servlet.WebUtil.*;

import java.io.IOException;

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

import och.api.exception.ExpectedException;
import och.api.exception.user.AccessDeniedException;
import och.api.exception.web.Show404PageExcepion;

import org.apache.commons.logging.Log;

public abstract class BaseErrorsServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    public static final String DEFAULT_ERROR_JSP_PATH = "/WEB-INF/jsp/error/error.jsp";

    public static final String ERROR_EXCEPTION = "javax.servlet.error.exception";
    public static final String ERROR_STATUS_CODE = "javax.servlet.error.status_code";

    Log log = getLog(getClass());

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        try {

            Integer statusCode = (Integer) req.getAttribute(ERROR_STATUS_CODE);
            if (statusCode != null) {
                setStatus(req, resp, statusCode);
            }

            Throwable t = (Throwable) req.getAttribute(ERROR_EXCEPTION);
            if (t != null) {
                processException(t, req, resp);
                ExpectedException.logError(log, t, "error while doing request");
            }

        } catch (Throwable e) {
            if (log.isErrorEnabled())
                log.error("Secondary exception", e);
        }

        String forwardPath = getForwardPath();
        try {
            forward(req, resp, forwardPath);
        } catch (Exception e) {
            if (log.isErrorEnabled())
                log.error("Can't show errors by path: " + forwardPath, e);
        }

    }

    protected String getForwardPath() {
        return DEFAULT_ERROR_JSP_PATH;
    }

    private void processException(Throwable t, HttpServletRequest req, HttpServletResponse resp) {

        if (t instanceof Show404PageExcepion) {
            set404Status(req, resp);
            return;
        }

        // ? HTTP ??  403 - ? 
        if (t instanceof AccessDeniedException) {
            set403Status(req, resp);
            return;
        }

    }

    public static void set404Status(HttpServletRequest req, HttpServletResponse resp) {
        setStatus(req, resp, HttpServletResponse.SC_NOT_FOUND);
    }

    public static void set403Status(HttpServletRequest req, HttpServletResponse resp) {
        setStatus(req, resp, HttpServletResponse.SC_FORBIDDEN);
    }

    public static void set503Status(HttpServletRequest req, HttpServletResponse resp) {
        setStatus(req, resp, HttpServletResponse.SC_SERVICE_UNAVAILABLE);
    }

    public static void setStatus(HttpServletRequest req, HttpServletResponse resp, int code) {
        req.setAttribute("statusCode", code);
        resp.setStatus(code);
    }

}