001// Copyright 2007, 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 org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
018
019import java.io.IOException;
020
021/**
022 * Responsible for handling the return value provided by a component event handler method.
023 * <p/>
024 * There are two services built into Tapestry that implement this interface: ComponentEventResultProcessor (used for
025 * ordinary page-oriented requests, and distinguished by the @{@link org.apache.tapestry5.services.Traditional}
026 * and/or @{@link org.apache.tapestry5.ioc.annotations.Primary} marker annotations) and 
027 * AjaxComponentEventResultProcessor, used
028 * for Ajax requests (which typically return a partially rendered page), distinguished by the @{@link
029 * org.apache.tapestry5.services.Ajax} marker annotation.
030 * @param <T>
031 */
032@UsesMappedConfiguration(key = Class.class, value = ComponentEventResultProcessor.class)
033public interface ComponentEventResultProcessor<T>
034{
035    /**
036     * For a given, non-null return value from a component event method, construct and send a response.
037     *
038     * @param value the value returned from a method
039     * @throws RuntimeException if the value can not handled
040     */
041    void processResultValue(T value) throws IOException;
042}