ErrorServlet.java

/**
 * Copyright (c) Codice Foundation
 * <p/>
 * This 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 3 of the
 * License, or any later version.
 * <p/>
 * This program 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. A copy of the GNU Lesser General Public License
 * is distributed along with this program and can be found at
 * <http://www.gnu.org/licenses/lgpl.html>.
 */
package org.codice.ddf.platform.error.servlet;

import java.io.IOException;

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

import org.codice.ddf.platform.error.handler.ErrorHandler;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.FrameworkUtil;
import org.osgi.framework.ServiceReference;

public class ErrorServlet extends HttpServlet {

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

    public static final String ERROR_EXCEPTION_TYPE = "javax.servlet.error.exception_type";

    public static final String ERROR_MESSAGE = "javax.servlet.error.message";

    public static final String ERROR_REQUEST_URI = "javax.servlet.error.request_uri";

    public static final String ERROR_SERVLET_NAME = "javax.servlet.error.servlet_name";

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

    private ErrorHandler errorHandler;

    public void init() {
        setErrorHandler();
    }

    public void setErrorHandler() {
        if (errorHandler == null) {
            Bundle bundle = FrameworkUtil.getBundle(ErrorServlet.class);
            if (bundle != null) {
                BundleContext bundleContext = bundle.getBundleContext();
                if (bundleContext != null) {
                    ServiceReference<ErrorHandler> serviceReference = bundleContext
                            .getServiceReference(ErrorHandler.class);
                    if (serviceReference != null) {
                        errorHandler = bundleContext.getService(serviceReference);
                    }
                }
            }
        }
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        Object codeObj = request.getAttribute(ERROR_STATUS_CODE);
        Object messageObj = request.getAttribute(ERROR_MESSAGE);
        Object typeObj = request.getAttribute(ERROR_EXCEPTION_TYPE);
        Throwable throwable = (Throwable) request.getAttribute(ERROR_EXCEPTION);
        String uri = (String) request.getAttribute(ERROR_REQUEST_URI);
        String code = "0";
        if (codeObj != null) {
            code = codeObj.toString();
        }
        String type = "";
        if (typeObj != null) {
            type = typeObj.toString();
        }
        String message = "";
        if (messageObj != null) {
            message = messageObj.toString();
        }

        setErrorHandler();

        if (errorHandler != null) {
            errorHandler.handleError(Integer.valueOf(code), message, type, throwable, uri, request,
                    response);
        } else {
            org.eclipse.jetty.server.handler.ErrorHandler jettyErrorHandler = new org.eclipse.jetty.server.handler.ErrorHandler();
            jettyErrorHandler
                    .handle(request.getRequestURI(), (org.eclipse.jetty.server.Request) request,
                            request, response);
        }
    }
}