001// Copyright 2006, 2007, 2008, 2009, 2011 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.internal.services;
016
017import org.apache.tapestry5.ComponentResourcesCommon;
018import org.apache.tapestry5.internal.structure.Page;
019import org.apache.tapestry5.services.pageload.ComponentResourceSelector;
020
021/**
022 * Instantiates a fully loaded, configured instance of a Tapestry page. This is a recursive process, since part of
023 * loading a page is to load the page elements for the page, many of which are components. Further, in some cases, the
024 * full component tree is not identified until after each component's template is loaded. Pages are instantiated once
025 * for each {@link ComponentResourceSelector} (prior to 5.3, once for each locale; prior to 5.1, for locale and pooled).
026 * 
027 * @see RequestPageCache
028 */
029public interface PageLoader
030{
031    /**
032     * Loads the page for the indicated selector.
033     * 
034     * @param pageName
035     *            the <em>canonicalized</em> logical name of the page, which will be made available via
036     *            {@link Page#getName()} and {@link ComponentResourcesCommon#getPageName()} (for any component within
037     *            the page).
038     * @param selector
039     *            Encapsulates the locale and other information used to select the component's
040     *            template and message catalog resources.
041     */
042    Page loadPage(String pageName, ComponentResourceSelector selector);
043}