Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
ApplicationServlet |
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1 | // Copyright 2004, 2005 The Apache Software Foundation |
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2 | // |
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3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
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4 | // you may not use this file except in compliance with the License. |
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5 | // You may obtain a copy of the License at |
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6 | // |
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7 | // http://www.apache.org/licenses/LICENSE-2.0 |
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8 | // |
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9 | // Unless required by applicable law or agreed to in writing, software |
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10 | // distributed under the License is distributed on an "AS IS" BASIS, |
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11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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12 | // See the License for the specific language governing permissions and |
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13 | // limitations under the License. |
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14 | ||
15 | package org.apache.tapestry; |
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16 | ||
17 | import org.apache.commons.logging.Log; |
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18 | import org.apache.commons.logging.LogFactory; |
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19 | import org.apache.hivemind.ClassResolver; |
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20 | import org.apache.hivemind.ErrorHandler; |
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21 | import org.apache.hivemind.Registry; |
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22 | import org.apache.hivemind.Resource; |
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23 | import org.apache.hivemind.impl.DefaultClassResolver; |
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24 | import org.apache.hivemind.impl.RegistryBuilder; |
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25 | import org.apache.hivemind.impl.StrictErrorHandler; |
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26 | import org.apache.hivemind.impl.XmlModuleDescriptorProvider; |
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27 | import org.apache.hivemind.util.ContextResource; |
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28 | import org.apache.tapestry.services.ApplicationInitializer; |
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29 | import org.apache.tapestry.services.ServletRequestServicer; |
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30 | import org.apache.tapestry.util.exception.ExceptionAnalyzer; |
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31 | ||
32 | import javax.servlet.ServletConfig; |
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33 | import javax.servlet.ServletContext; |
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34 | import javax.servlet.ServletException; |
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35 | import javax.servlet.http.HttpServlet; |
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36 | import javax.servlet.http.HttpServletRequest; |
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37 | import javax.servlet.http.HttpServletResponse; |
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38 | import java.io.IOException; |
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39 | import java.util.Locale; |
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40 | ||
41 | /** |
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42 | * Links a servlet container with a Tapestry application. The servlet init parameter |
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43 | * <code>org.apache.tapestry.application-specification</code> should be set to the complete |
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44 | * resource path (within the classpath) to the application specification, i.e., |
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45 | * <code>/com/foo/bar/MyApp.application</code>. As of release 4.0, this servlet will also create |
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46 | * a HiveMind Registry and manage it. |
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47 | * |
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48 | * @author Howard Lewis Ship |
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49 | * @see org.apache.tapestry.services.ApplicationInitializer |
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50 | * @see org.apache.tapestry.services.ServletRequestServicer |
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51 | */ |
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52 | ||
53 | 0 | public class ApplicationServlet extends HttpServlet |
54 | { |
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55 | private static final long serialVersionUID = -8046042689991538059L; |
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56 | ||
57 | /** |
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58 | * Prefix used to store the HiveMind Registry into the ServletContext. This string is suffixed |
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59 | * with the servlet name (in case multiple Tapestry applications are executing within a single |
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60 | * web application). |
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61 | * |
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62 | * @since 4.0 |
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63 | */ |
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64 | ||
65 | private static final String REGISTRY_KEY_PREFIX = "org.apache.tapestry.Registry:"; |
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66 | ||
67 | 0 | private static final Log LOG = LogFactory.getLog(ApplicationServlet.class); |
68 | ||
69 | /** |
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70 | * @since 2.3 |
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71 | */ |
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72 | ||
73 | private ClassResolver _resolver; |
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74 | ||
75 | /** |
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76 | * The key used to store the registry into the ServletContext. |
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77 | * |
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78 | * @since 4.0 |
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79 | */ |
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80 | ||
81 | private String _registryKey; |
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82 | ||
83 | /** |
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84 | * @since 4.0 |
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85 | */ |
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86 | ||
87 | private Registry _registry; |
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88 | ||
89 | /** |
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90 | * @since 4.0 |
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91 | */ |
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92 | private ServletRequestServicer _requestServicer; |
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93 | ||
94 | /** |
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95 | * Invokes {@link #doService(HttpServletRequest, HttpServletResponse)}. |
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96 | * |
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97 | * @since 1.0.6 |
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98 | */ |
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99 | ||
100 | public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, |
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101 | ServletException |
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102 | { |
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103 | 0 | doService(request, response); |
104 | 0 | } |
105 | ||
106 | /** |
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107 | * Handles the GET and POST requests. Performs the following: |
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108 | * |
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109 | * <ul> |
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110 | * <li> |
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111 | * Invokes {@link org.apache.hivemind.Registry#setupThread()} |
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112 | * </li> |
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113 | * <li> |
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114 | * Invokes {@link ServletRequestServicer#service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)}. |
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115 | * </li> |
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116 | * </ul> |
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117 | */ |
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118 | ||
119 | protected void doService(HttpServletRequest request, HttpServletResponse response) |
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120 | throws IOException, ServletException |
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121 | { |
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122 | try |
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123 | { |
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124 | 0 | _registry.setupThread(); |
125 | ||
126 | 0 | _requestServicer.service(request, response); |
127 | } |
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128 | 0 | catch (ServletException ex) |
129 | { |
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130 | 0 | log("ServletException", ex); |
131 | ||
132 | 0 | show(ex); |
133 | ||
134 | // Rethrow it. |
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135 | ||
136 | 0 | throw ex; |
137 | } |
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138 | 0 | catch (IOException ex) |
139 | { |
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140 | 0 | log("IOException", ex); |
141 | ||
142 | 0 | show(ex); |
143 | ||
144 | // Rethrow it. |
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145 | ||
146 | 0 | throw ex; |
147 | } |
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148 | finally |
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149 | { |
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150 | 0 | _registry.cleanupThread(); |
151 | 0 | } |
152 | 0 | } |
153 | ||
154 | protected void show(Exception ex) |
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155 | { |
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156 | 0 | System.err.println("\n\n**********************************************************\n\n"); |
157 | ||
158 | 0 | new ExceptionAnalyzer().reportException(ex, System.err); |
159 | ||
160 | 0 | System.err.println("\n**********************************************************\n"); |
161 | ||
162 | 0 | } |
163 | ||
164 | /** |
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165 | * Invokes {@link #doService(HttpServletRequest, HttpServletResponse)}. |
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166 | */ |
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167 | ||
168 | public void doPost(HttpServletRequest request, HttpServletResponse response) |
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169 | throws IOException, ServletException |
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170 | { |
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171 | 0 | doService(request, response); |
172 | 0 | } |
173 | ||
174 | /** |
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175 | * Reads the application specification when the servlet is first initialized. All |
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176 | * {@link IEngine engine instances}will have access to the specification via the servlet. |
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177 | * |
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178 | * @see #constructRegistry(ServletConfig) |
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179 | * @see #createClassResolver() |
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180 | */ |
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181 | ||
182 | public void init(ServletConfig config) throws ServletException |
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183 | { |
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184 | 0 | String name = config.getServletName(); |
185 | ||
186 | 0 | _registryKey = REGISTRY_KEY_PREFIX + name; |
187 | ||
188 | 0 | long startTime = System.currentTimeMillis(); |
189 | 0 | long elapsedToRegistry = 0; |
190 | ||
191 | 0 | super.init(config); |
192 | ||
193 | 0 | _resolver = createClassResolver(); |
194 | ||
195 | try |
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196 | { |
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197 | 0 | _registry = constructRegistry(config); |
198 | ||
199 | 0 | elapsedToRegistry = System.currentTimeMillis() - startTime; |
200 | ||
201 | 0 | initializeApplication(); |
202 | ||
203 | 0 | config.getServletContext().setAttribute(_registryKey, _registry); |
204 | } |
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205 | 0 | catch (Exception ex) |
206 | { |
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207 | 0 | show(ex); |
208 | ||
209 | 0 | throw new ServletException(TapestryMessages.servletInitFailure(ex), ex); |
210 | 0 | } |
211 | ||
212 | 0 | long elapsedOverall = System.currentTimeMillis() - startTime; |
213 | ||
214 | 0 | LOG.info(TapestryMessages.servletInit(name, elapsedToRegistry, elapsedOverall)); |
215 | 0 | } |
216 | ||
217 | /** |
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218 | * Invoked from {@link #init(ServletConfig)}to create a resource resolver for the servlet |
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219 | * (which will utlimately be shared and used through the application). |
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220 | * <p> |
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221 | * This implementation constructs a {@link DefaultClassResolver}, subclasses may provide a |
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222 | * different implementation. |
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223 | * |
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224 | * @see DefaultClassResolver |
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225 | * @since 2.3 |
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226 | */ |
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227 | ||
228 | protected ClassResolver createClassResolver() |
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229 | { |
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230 | 0 | return new DefaultClassResolver(); |
231 | } |
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232 | ||
233 | /** |
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234 | * Invoked from {@link #init(ServletConfig)}to construct the Registry to be used by the |
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235 | * application. |
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236 | * <p> |
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237 | * This looks in the standard places (on the classpath), but also in the WEB-INF/name and |
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238 | * WEB-INF folders (where name is the name of the servlet). |
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239 | * |
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240 | * @since 4.0 |
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241 | */ |
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242 | protected Registry constructRegistry(ServletConfig config) |
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243 | { |
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244 | 0 | ErrorHandler errorHandler = constructErrorHandler(config); |
245 | ||
246 | 0 | RegistryBuilder builder = new RegistryBuilder(errorHandler); |
247 | ||
248 | 0 | builder.addModuleDescriptorProvider(new XmlModuleDescriptorProvider(_resolver)); |
249 | ||
250 | 0 | String name = config.getServletName(); |
251 | 0 | ServletContext context = config.getServletContext(); |
252 | ||
253 | 0 | addModuleIfExists(builder, context, "/WEB-INF/" + name + "/hivemodule.xml"); |
254 | 0 | addModuleIfExists(builder, context, "/WEB-INF/hivemodule.xml"); |
255 | ||
256 | 0 | return builder.constructRegistry(Locale.getDefault()); |
257 | } |
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258 | ||
259 | /** |
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260 | * Invoked by {@link #constructRegistry(ServletConfig)} to create and return an |
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261 | * {@link ErrorHandler} instance to be used when constructing the Registry (and then to handle |
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262 | * any runtime exceptions). This implementation returns a new instance of |
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263 | * {@link org.apache.hivemind.impl.StrictErrorHandler}. |
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264 | * |
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265 | * @since 4.0 |
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266 | */ |
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267 | protected ErrorHandler constructErrorHandler(ServletConfig config) |
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268 | { |
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269 | 0 | return new StrictErrorHandler(); |
270 | } |
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271 | ||
272 | /** |
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273 | * Looks for a file in the servlet context; if it exists, it is expected to be a HiveMind module |
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274 | * descriptor, and is added to the builder. |
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275 | * |
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276 | * @since 4.0 |
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277 | */ |
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278 | ||
279 | protected void addModuleIfExists(RegistryBuilder builder, ServletContext context, String path) |
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280 | { |
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281 | 0 | Resource r = new ContextResource(context, path); |
282 | ||
283 | 0 | if (r.getResourceURL() == null) |
284 | 0 | return; |
285 | ||
286 | 0 | builder.addModuleDescriptorProvider(new XmlModuleDescriptorProvider(_resolver, r)); |
287 | 0 | } |
288 | ||
289 | /** |
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290 | * Invoked from {@link #init(ServletConfig)}, after the registry has been constructed, to |
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291 | * bootstrap the application via the <code>tapestry.MasterApplicationInitializer</code> |
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292 | * service. |
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293 | * |
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294 | * @since 4.0 |
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295 | */ |
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296 | protected void initializeApplication() |
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297 | { |
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298 | 0 | ApplicationInitializer ai = (ApplicationInitializer) _registry.getService( |
299 | "tapestry.init.MasterInitializer", |
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300 | ApplicationInitializer.class); |
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301 | ||
302 | 0 | ai.initialize(this); |
303 | ||
304 | 0 | _registry.cleanupThread(); |
305 | ||
306 | 0 | _requestServicer = (ServletRequestServicer) _registry.getService( |
307 | "tapestry.request.ServletRequestServicer", |
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308 | ServletRequestServicer.class); |
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309 | 0 | } |
310 | ||
311 | /** |
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312 | * Shuts down the registry (if it exists). |
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313 | * |
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314 | * @since 4.0 |
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315 | */ |
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316 | public void destroy() |
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317 | { |
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318 | 0 | getServletContext().removeAttribute(_registryKey); |
319 | ||
320 | 0 | if (_registry != null) |
321 | { |
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322 | 0 | _registry.shutdown(); |
323 | 0 | _registry = null; |
324 | } |
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325 | ||
326 | 0 | super.destroy(); |
327 | 0 | } |
328 | } |