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.internal.structure.Page; 018import org.apache.tapestry5.runtime.PageLifecycleListener; 019 020/** 021 * Per-thread service that caches page instances for the duration of the request, and is also responsible for tracking 022 * the active page (the page which will ultimately render the response). 023 * <p/> 024 * Since {@link org.apache.tapestry5.internal.structure.Page} is internal, most user-code should use the 025 * {@link org.apache.tapestry5.services.ComponentSource} service instead. 026 * <p> 027 * Starting in 5.2, page instances are shared (with externalized mutable state), not pooled, but the cache is still 028 * useful for managing the page's {@linkplain PageLifecycleListener lifecycle}. 029 */ 030public interface RequestPageCache 031{ 032 /** 033 * Gets the page via its page name, in the current locale. The logical page name is resolved to a class name, which 034 * is used to obtain the page (from the page pool). Note that under certain circumstances, a page may have multiple 035 * names (even beyond simple case-insensitivity), and RequestPageCache caches correctly. 036 * 037 * @param pageName 038 * the name of the page to retrieve (this is the logical page name, not the fully qualified class 039 * name) 040 * @return a page instance reserved for this request 041 * @throws IllegalArgumentException 042 * if the name can not be resolved to a page instance 043 */ 044 Page get(String pageName); 045}