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
015package org.apache.tapestry5.services;
016
017import org.apache.tapestry5.EventConstants;
018import org.apache.tapestry5.runtime.Component;
019
020/**
021 * Used by classes that need to retrieve a component by its complete id, or a page by its logical page name or root
022 * component class. The complete id is the logical name of the containing page, a colon, and the nested component id. It
023 * may also just be the page name (for the root component of a page).
024 */
025public interface ComponentSource
026{
027    /**
028     * Gets a component by its {@linkplain org.apache.tapestry5.ComponentResourcesCommon#getCompleteId() complete id}.
029     * If the component id is for a mixin, then the mixin attached to the component will be returned. A mixin's complete
030     * id is its container's complete id, suffixed with "$" and the mixin's id (its simple class name).
031     * 
032     * @param completeId
033     *            complete component id (case insensitive)
034     * @return the component
035     * @throws IllegalArgumentException
036     *             if the component can not be found
037     * @see org.apache.tapestry5.ComponentResourcesCommon#getCompleteId()
038     */
039    Component getComponent(String completeId);
040
041    /**
042     * Returns the page identified by its logical page name. A logical page name is the short form of a page name often
043     * emebedded into URLs.
044     * 
045     * @param pageName
046     *            the logical page name
047     * @return the corresponding page's root component
048     * @throws IllegalArgumentException
049     *             if the page can not be found
050     */
051    Component getPage(String pageName);
052
053    /**
054     * A convienience for obtaining a page instance via a class instance. This is provided so as to be refactoring
055     * safe. The pageClass is simply converted to a class name and this is used to locate a page instance.
056     * 
057     * @param pageClass
058     *            used to locate the page instance
059     * @return the page instance
060     */
061    Component getPage(Class pageClass);
062
063    /**
064     * Returns the <em>active page</em>, as defined by {@link RequestGlobals#getActivePageName()}. This is the primary
065     * page for handling the current request, the page which will be {@linkplain EventConstants#ACTIVATE activated} for
066     * the request.
067     * The identity of the active page is not known until the correct {@link Dispatcher} determines this.
068     * 
069     * @return the active page, or null if no active page is yet identified
070     * @since 5.2.0
071     */
072    Component getActivePage();
073}