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}