001    // Copyright 2005 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    
015    package org.apache.tapestry.error;
016    
017    import org.apache.tapestry.IRequestCycle;
018    
019    /**
020     * Invoked by the {@link org.apache.tapestry.IEngine} if there's an uncaught exception
021     * (checked or runtime) processing a request. The ExceptionPresenter is responsible for presenting a
022     * exception message (or description) to the user. The default implementation activates the
023     * "Exception" page, but it is common to override this to do something application specific
024     * (typically, return to the Home page and display an error message there). This service also
025     * provides a good hook for creating a server-side log of exceptions.
026     * 
027     * @author Howard M. Lewis Ship
028     * @since 4.0
029     * @see RequestExceptionReporter
030     */
031    public interface ExceptionPresenter
032    {
033        /**
034         * Report the exception and provide some response to the user in lieu of the expected result
035         * page.
036         * 
037         * @param cycle
038         *            the current request cycle
039         * @param cause
040         *            the exception that was caught
041         */
042    
043        public void presentException(IRequestCycle cycle, Throwable cause);
044    }