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;
014
015import org.apache.tapestry5.Link;
016import org.apache.tapestry5.services.linktransform.ComponentEventLinkTransformer;
017import org.apache.tapestry5.services.linktransform.PageRenderLinkTransformer;
018
019/**
020 * Responsible for creating {@link org.apache.tapestry5.Link}s for page render requests and for component event
021 * requests, and for parsing incoming paths to identify requests that are component event or page render requests. This
022 * centralizes some logic that was scattered about in Tapestry 5.0.
023 * 
024 * @since 5.1.0.1
025 */
026public interface ComponentEventLinkEncoder
027{
028    /**
029     * Creates a Link that encapsulates a page render request, including activation context <em>and {@link
030     * org.apache.tapestry5.services.PersistentLocale} (if set)</em>.
031     * Passes the resulting Link through the {@link PageRenderLinkTransformer} chain of command, returning
032     * the result.
033     * 
034     * @param parameters
035     *            defining page to render and context
036     * @return link for the page render
037     */
038    Link createPageRenderLink(PageRenderRequestParameters parameters);
039
040    /**
041     * Creates a link that encapsulates a component event request, including <em>{@link
042     * org.apache.tapestry5.services.PersistentLocale} (if set)</em>.
043     *
044     * Forms:
045     * <ul>
046     * <li>/context/pagename:eventname -- event on the page, no action context</li>
047     * <li>/context/pagename:eventname/foo/bar -- event on the page with action context "foo", "bar"</li>
048     * <li>/context/pagename.foo.bar -- event on component foo.bar within the page, default event, no action context</li>
049     * <li>/context/pagename.foo.bar/baz.gnu -- event on component foo.bar within the page, default event, with action
050     * context "baz", "gnu"</li>
051     * <li>/context/pagename.bar.baz:eventname/foo/gnu -- event on component bar.baz within the page with action context
052     * "foo" , "gnu"</li>
053     * </ul>
054     *
055     * The persistent locale may be placed in between the context name and the page name, i.e., "/context/fr/SomePage".
056     *
057     * In many cases the context name is blank, so the path begins with a "/" and then the locale name or page name.
058     *
059     * The page name portion may itself consist of a series of folder names, i.e., "admin/user/create". The context
060     * portion isn't the concern of this code, since {@link org.apache.tapestry5.services.Request#getPath()} will
061     * already have stripped that off. We can act as if the context is always "/" (the path always starts with a slash).
062     *
063     * Passes the resulting Link through the {@link ComponentEventLinkTransformer} chain of command, returning the
064     * result.
065     * 
066     * @param parameters
067     *            defining page, component, activation context and other details
068     * @param forForm
069     *            true if the event link will trigger a form submission
070     * @return link for the component event
071     */
072    Link createComponentEventLink(ComponentEventRequestParameters parameters, boolean forForm);
073
074    /**
075     * Checks the request, primarily the {@linkplain org.apache.tapestry5.services.Request#getPath() path}, to determine
076     * the if the request is a component event request. As a side-effect (necessary for historical reasons), responsible
077     * for setting the locale for the thread, including the {@link org.apache.tapestry5.services.PersistentLocale} ...
078     * but only if the locale is a component event.
079     * 
080     * @param request
081     *            incoming request
082     * @return component event request details, if a component event request
083     */
084    ComponentEventRequestParameters decodeComponentEventRequest(Request request);
085
086    /**
087     * Checks the request, primarily the {@linkplain org.apache.tapestry5.services.Request#getPath() path}, to determine
088     * the if the request is a page render request. As a side-effect (necessary for historical reasons), responsible for
089     * setting the locale for the thread, including the {@link org.apache.tapestry5.services.PersistentLocale} ... but
090     * only if the request is a page render.
091     * 
092     * @param request
093     *            incoming request
094     * @return page render request details, if a page render request
095     */
096    PageRenderRequestParameters decodePageRenderRequest(Request request);
097}