001 // Copyright 2005 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.tapestry.portlet; 016 017 import java.io.IOException; 018 019 import javax.portlet.PortletRequest; 020 021 import org.apache.tapestry.IRequestCycle; 022 import org.apache.tapestry.engine.IEngineService; 023 import org.apache.tapestry.engine.ILink; 024 import org.apache.tapestry.services.ServiceConstants; 025 026 /** 027 * Responsible for rendering out a page; a Portlet render URL is built during action processing that 028 * stores the active page; this is the page that will be rendered. The render service is (typically) 029 * the only service that operates during a portlet RenderRequest. All other services will be an 030 * ActionRequest that (via {@link org.apache.tapestry.portlet.PortletResponseRenderer}, writes 031 * query parameters to activate this service during the render request. 032 * <p> 033 * Problematic is is anything related to the portlet mode or window state. As per the Portlet spec, 034 * when the user clicks the "help" or "edit" buttons (or the minimize, maximize, etc.), this causes 035 * a new RenderRequest, but explicitly keeps the render parameters set by the most recent 036 * ActionRequest. But what Tapestry needs is to detect that the mode or state has changed and select 037 * a different page to render the response. So we store the mode and state in effect when the 038 * ActionRequest executed as two more query parameters, and detect changes to mode and state that 039 * way. If there is a change, then we ignore the page query parameter and use the 040 * {@link PortletPageResolver} to figure out the correct page to display instead. 041 * 042 * @author Howard M. Lewis Ship 043 * @since 4.0 044 * @see org.apache.tapestry.services.impl.ResponseRendererImpl 045 */ 046 public class RenderService implements IEngineService 047 { 048 private PortletRequest _request; 049 050 private PortletRenderer _portletRenderer; 051 052 private PortletPageResolver _pageResolver; 053 054 public ILink getLink(boolean post, Object parameter) 055 { 056 throw new UnsupportedOperationException(PortletMessages.unsupportedMethod("getLink")); 057 } 058 059 public void service(IRequestCycle cycle) throws IOException 060 { 061 String pageName = getPageNameToRender(cycle); 062 063 _portletRenderer.renderPage(cycle, pageName); 064 } 065 066 private String getPageNameToRender(IRequestCycle cycle) 067 { 068 if (isStateChange(cycle)) 069 return _pageResolver.getPageNameForRequest(cycle); 070 071 return cycle.getParameter(ServiceConstants.PAGE); 072 } 073 074 /** 075 * Returns true if the portlet mode or the window state has changed since. The values stored 076 * previously (during an action request) are compared to the current values. 077 */ 078 079 boolean isStateChange(IRequestCycle cycle) 080 { 081 String expectedPortletMode = cycle.getParameter(PortletConstants.PORTLET_MODE); 082 String expectedWindowState = cycle.getParameter(PortletConstants.WINDOW_STATE); 083 084 return !(_request.getPortletMode().toString().equals(expectedPortletMode) && _request 085 .getWindowState().toString().equals(expectedWindowState)); 086 087 } 088 089 public String getName() 090 { 091 return PortletConstants.RENDER_SERVICE; 092 } 093 094 public void setPortletRenderer(PortletRenderer portletRenderer) 095 { 096 _portletRenderer = portletRenderer; 097 } 098 099 public void setRequest(PortletRequest request) 100 { 101 _request = request; 102 } 103 104 public void setPageResolver(PortletPageResolver pageResolver) 105 { 106 _pageResolver = pageResolver; 107 } 108 }