001    // Copyright 2006, 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    
015    package org.apache.tapestry5.services;
016    
017    import org.apache.tapestry5.ioc.annotations.UsesOrderedConfiguration;
018    
019    import java.io.IOException;
020    
021    /**
022     * Handler interface for component event requests. Component event requests <em>do things</em> such as process a form
023     * submission or otherwise change state. In the majority of cases, after the component event, a redirect response is
024     * sent to the client which, in turn, causes a page render.
025     * <p/>
026     * The ComponentEventRequestHandler service is a pipeline, allowing extensibility via contributed {@linkplain
027     * org.apache.tapestry5.services.ComponentEventRequestFilter filters}.    It may be distinguished by the @{@link
028     * org.apache.tapestry5.services.Traditional} marker annotation.
029     * <p/>
030     * A second service, AjaxComponentEventRequestHandler is also a pipeline and may be distinguished by the @{@link
031     * org.apache.tapestry5.services.Ajax} marker annotation.
032     *
033     * @see org.apache.tapestry5.corelib.components.ActionLink
034     * @see org.apache.tapestry5.corelib.components.Form
035     */
036    @UsesOrderedConfiguration(ComponentEventRequestFilter.class)
037    public interface ComponentEventRequestHandler
038    {
039        /**
040         * Handler for a component action request which will trigger an event on a component and use the return value to
041         * send a response to the client (typically, a redirect to a page render URL).
042         *
043         * @param parameters defining the requst
044         */
045        void handle(ComponentEventRequestParameters parameters) throws IOException;
046    }