    001// Copyright 2006, 2008 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007//     http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.services;
    016
    017import java.io.IOException;
    018
    019/**
    020 * Service invoked when an uncaught exception occurs. The error handler is responsible for providing a response to the
    021 * user to describe the error.
    022 */
    023public interface RequestExceptionHandler
    024{
    025    /**
    026     * Reponsible for handling the error <em>in some way</em> and providing <em>some response</em> to the client. A
    027     * default implementation may render an error response page.
    028     * <p/>
    029     * <p/>
    030     * The handler is also responsible for setting the response status and the X-Tapestry-ErrorMessage response header.
    031     * These are very important in Ajax requests to allow the client-side logic to detect the error and present it to
    032     * the user.
    033     *
    034     * @param exception uncaught exception to be reported
    035     * @throws IOException
    036     */
    037    void handleRequestException(Throwable exception) throws IOException;
    038}