001 // Copyright 2004, 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.html; 016 017 import java.util.Date; 018 import java.util.Iterator; 019 020 import org.apache.hivemind.HiveMind; 021 import org.apache.tapestry.AbstractComponent; 022 import org.apache.tapestry.IAsset; 023 import org.apache.tapestry.IMarkupWriter; 024 import org.apache.tapestry.IPage; 025 import org.apache.tapestry.IRender; 026 import org.apache.tapestry.IRequestCycle; 027 import org.apache.tapestry.Tapestry; 028 import org.apache.tapestry.coerce.ValueConverter; 029 import org.apache.tapestry.engine.IEngineService; 030 import org.apache.tapestry.engine.ILink; 031 import org.apache.tapestry.spec.IApplicationSpecification; 032 033 /** 034 * Component for creating a standard 'shell' for a page, which comprises the <html> and 035 * <head> portions of the page. [ <a 036 * href="../../../../../ComponentReference/Shell.html">Component Reference </a>] 037 * <p> 038 * Specifically does <em>not</em> provide a <body> tag, that is usually accomplished using a 039 * {@link Body} component. 040 * 041 * @author Howard Lewis Ship 042 */ 043 044 public abstract class Shell extends AbstractComponent 045 { 046 private static final String generatorContent = "Tapestry Application Framework, version " 047 + Tapestry.VERSION; 048 049 protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle) 050 { 051 long startTime = 0; 052 053 boolean rewinding = cycle.isRewinding(); 054 055 if (!rewinding) 056 { 057 startTime = System.currentTimeMillis(); 058 059 writeDocType(writer, cycle); 060 061 IPage page = getPage(); 062 063 writer.comment("Application: " + getApplicationSpecification().getName()); 064 065 writer.comment("Page: " + page.getPageName()); 066 writer.comment("Generated: " + new Date()); 067 068 writer.begin("html"); 069 writer.println(); 070 writer.begin("head"); 071 writer.println(); 072 073 writeMetaTag(writer, "name", "generator", generatorContent); 074 075 if (getRenderContentType()) 076 writeMetaTag(writer, "http-equiv", "Content-Type", writer.getContentType()); 077 078 if (getRenderBaseTag()) 079 getBaseTagWriter().render(writer, cycle); 080 081 writer.begin("title"); 082 083 writer.print(getTitle()); 084 writer.end(); // title 085 writer.println(); 086 087 IRender delegate = getDelegate(); 088 089 if (delegate != null) 090 delegate.render(writer, cycle); 091 092 IAsset stylesheet = getStylesheet(); 093 094 if (stylesheet != null) 095 writeStylesheetLink(writer, cycle, stylesheet); 096 097 Iterator i = (Iterator) getValueConverter().coerceValue( 098 getStylesheets(), 099 Iterator.class); 100 101 while (i.hasNext()) 102 { 103 stylesheet = (IAsset) i.next(); 104 105 writeStylesheetLink(writer, cycle, stylesheet); 106 } 107 108 writeRefresh(writer, cycle); 109 110 writer.end(); // head 111 } 112 113 // Render the body, the actual page content 114 115 renderBody(writer, cycle); 116 117 if (!rewinding) 118 { 119 writer.end(); // html 120 writer.println(); 121 122 long endTime = System.currentTimeMillis(); 123 124 writer.comment("Render time: ~ " + (endTime - startTime) + " ms"); 125 } 126 127 } 128 129 private void writeDocType(IMarkupWriter writer, IRequestCycle cycle) 130 { 131 // This is the real code 132 String doctype = getDoctype(); 133 if (HiveMind.isNonBlank(doctype)) 134 { 135 writer.printRaw("<!DOCTYPE " + doctype + ">"); 136 writer.println(); 137 } 138 } 139 140 private void writeStylesheetLink(IMarkupWriter writer, IRequestCycle cycle, IAsset stylesheet) 141 { 142 writer.beginEmpty("link"); 143 writer.attribute("rel", "stylesheet"); 144 writer.attribute("type", "text/css"); 145 writer.attribute("href", stylesheet.buildURL()); 146 writer.println(); 147 } 148 149 private void writeRefresh(IMarkupWriter writer, IRequestCycle cycle) 150 { 151 int refresh = getRefresh(); 152 153 if (refresh <= 0) 154 return; 155 156 // Here comes the tricky part ... have to assemble a complete URL 157 // for the current page. 158 159 IEngineService pageService = getPageService(); 160 String pageName = getPage().getPageName(); 161 162 ILink link = pageService.getLink(false, pageName); 163 164 StringBuffer buffer = new StringBuffer(); 165 buffer.append(refresh); 166 buffer.append("; URL="); 167 buffer.append(link.getAbsoluteURL()); 168 169 writeMetaTag(writer, "http-equiv", "Refresh", buffer.toString()); 170 } 171 172 private void writeMetaTag(IMarkupWriter writer, String key, String value, String content) 173 { 174 writer.beginEmpty("meta"); 175 writer.attribute(key, value); 176 writer.attribute("content", content); 177 writer.println(); 178 } 179 180 public abstract IRender getDelegate(); 181 182 public abstract int getRefresh(); 183 184 public abstract IAsset getStylesheet(); 185 186 public abstract Object getStylesheets(); 187 188 public abstract String getTitle(); 189 190 public abstract String getDoctype(); 191 192 public abstract boolean getRenderContentType(); 193 194 /** @since 4.0 */ 195 public abstract ValueConverter getValueConverter(); 196 197 /** @since 4.0 */ 198 199 public abstract IEngineService getPageService(); 200 201 /** @since 4.0 */ 202 203 public abstract IApplicationSpecification getApplicationSpecification(); 204 205 /** @since 4.0 */ 206 207 public abstract IRender getBaseTagWriter(); 208 209 /** @since 4.0.1 */ 210 211 public abstract boolean getRenderBaseTag(); 212 }