001    // Copyright 2010, 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    
015    package org.apache.tapestry5.internal.services;
016    
017    import org.apache.tapestry5.internal.structure.Page;
018    import org.apache.tapestry5.ioc.Resource;
019    import org.apache.tapestry5.services.dynamic.DynamicTemplate;
020    import org.apache.tapestry5.services.pageload.ComponentRequestSelectorAnalyzer;
021    import org.apache.tapestry5.services.pageload.ComponentResourceSelector;
022    
023    import java.util.Set;
024    
025    /**
026     * Access to localized page instances (which are now shared singletons, starting in release 5.2).
027     * This service is a wrapper around the {@link PageLoader} that caches the loaded pages.
028     *
029     * @since 5.2.0
030     */
031    public interface PageSource
032    {
033        /**
034         * Clears the source's cache of loaded pages. This occurs when an outside change to the world invalidates
035         * created page instances. Introduced to handle the case where a page has a {@link DynamicTemplate}, but the
036         * underlying {@link Resource} is noticed to have changed.
037         *
038         * @since 5.3
039         */
040        void clearCache();
041    
042        /**
043         * Returns a loaded instance of the indicated page, using the Locale and other information
044         * from the {@link ComponentResourceSelector} obtained from the {@link ComponentRequestSelectorAnalyzer}.
045         *
046         * @param canonicalPageName
047         * @return existing, or newly created, page instance
048         */
049        Page getPage(String canonicalPageName);
050    
051        /**
052         * Returns all currently loaded pages. This will include any previously loaded pages not yet reclaimed by the
053         * garbage collector, and may include the same page loaded for different {@link ComponentResourceSelector}s. This is needed
054         * for reporting purposes only.
055         *
056         * @see org.apache.tapestry5.corelib.pages.PageCatalog
057         * @since 5.3
058         */
059        Set<Page> getAllPages();
060    }