001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005// http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.services.linktransform;
014
015import org.apache.tapestry5.http.Link;
016import org.apache.tapestry5.http.services.Request;
017import org.apache.tapestry5.internal.services.ComponentEventDispatcher;
018import org.apache.tapestry5.ioc.annotations.UsesOrderedConfiguration;
019import org.apache.tapestry5.services.ComponentEventRequestParameters;
020import org.apache.tapestry5.services.LocalizationSetter;
021
022/**
023 * Allows for selective replacement of the default {@link Link} used to represent a component event request.
024 * This is a service, but also the contribution to the service, as a chain of command.
025 *
026 * This transformer follows the same pattern as {@link PageRenderLinkTransformer}.
027 * 
028 * @since 5.2.0
029 */
030@UsesOrderedConfiguration(ComponentEventLinkTransformer.class)
031public interface ComponentEventLinkTransformer
032{
033    /**
034     * Allows the default Link created for the component event request to be replaced.
035     * 
036     * @param defaultLink
037     *            the default Link generated for a component event request
038     * @param parameters
039     *            used to create the default Link
040     * @return a replacement Link, or null
041     */
042    Link transformComponentEventLink(Link defaultLink, ComponentEventRequestParameters parameters);
043
044    /**
045     * Attempts to decode the page render request, to perform the opposite action for
046     * {@link #transformComponentEventLink(Link, ComponentEventRequestParameters)}. The transformer
047     * is also responsible for identifying the locale in the request (as part of the path, or as a
048     * query parameter or cookie) and setting the locale for the request.
049     *
050     * This method will be invoked from the {@link ComponentEventDispatcher} and a non-null value returned from this
051     * method will prevent the default
052     * {@link org.apache.tapestry5.services.ComponentEventLinkEncoder#decodeComponentEventRequest(Request)} method
053     * from being invoked.
054     * 
055     * @return decoded parameters, or null to proceed normally
056     * @see LocalizationSetter#setLocaleFromLocaleName(String)
057     */
058    ComponentEventRequestParameters decodeComponentEventRequest(Request request);
059}