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.http.services.Dispatcher;
019import org.apache.tapestry5.http.services.RequestGlobals;
020import org.apache.tapestry5.runtime.Component;
021
022/**
023 * Used by classes that need to retrieve a component by its complete id, or a page by its logical page name or root
024 * component class. The complete id is the logical name of the containing page, a colon, and the nested component id. It
025 * may also just be the page name (for the root component of a page).
026 */
027public interface ComponentSource
028{
029    /**
030     * Gets a component by its {@linkplain org.apache.tapestry5.ComponentResourcesCommon#getCompleteId() complete id}.
031     * If the component id is for a mixin, then the mixin attached to the component will be returned. A mixin's complete
032     * id is its container's complete id, suffixed with "$" and the mixin's id (its simple class name).
033     * 
034     * @param completeId
035     *            complete component id (case insensitive)
036     * @return the component
037     * @throws IllegalArgumentException
038     *             if the component can not be found
039     * @see org.apache.tapestry5.ComponentResourcesCommon#getCompleteId()
040     */
041    Component getComponent(String completeId);
042
043    /**
044     * Returns the page identified by its logical page name. A logical page name is the short form of a page name often
045     * emebedded into URLs.
046     * 
047     * @param pageName
048     *            the logical page name
049     * @return the corresponding page's root component
050     * @throws IllegalArgumentException
051     *             if the page can not be found
052     */
053    Component getPage(String pageName);
054
055    /**
056     * A convienience for obtaining a page instance via a class instance. This is provided so as to be refactoring
057     * safe. The pageClass is simply converted to a class name and this is used to locate a page instance.
058     * 
059     * @param pageClass
060     *            used to locate the page instance
061     * @return the page instance
062     */
063    Component getPage(Class pageClass);
064
065    /**
066     * Returns the <em>active page</em>, as defined by {@link RequestGlobals#getActivePageName()}. This is the primary
067     * page for handling the current request, the page which will be {@linkplain EventConstants#ACTIVATE activated} for
068     * the request.
069     * The identity of the active page is not known until the correct {@link Dispatcher} determines this.
070     * 
071     * @return the active page, or null if no active page is yet identified
072     * @since 5.2.0
073     */
074    Component getActivePage();
075}