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Java > Open Source Codes > org > directwebremoting > guice > DwrGuiceServlet


1 /*
2  * Copyright 2007 Tim Peierls
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.directwebremoting.guice;
17
18 import com.google.inject.Binding;
19 import com.google.inject.Inject;
20 import com.google.inject.Injector;
21 import com.google.inject.Key;
22 import com.google.inject.name.Named;
23
24 import java.util.ArrayList JavaDoc;
25 import java.util.List JavaDoc;
26 import static java.util.Map.Entry;
27
28 import javax.servlet.ServletConfig JavaDoc;
29 import javax.servlet.ServletContext JavaDoc;
30 import javax.servlet.ServletException JavaDoc;
31
32 import org.directwebremoting.extend.AjaxFilterManager;
33 import org.directwebremoting.extend.Configurator;
34 import org.directwebremoting.extend.ConverterManager;
35 import org.directwebremoting.extend.CreatorManager;
36 import org.directwebremoting.servlet.DwrServlet;
37 import org.directwebremoting.util.Logger;
38
39 import static org.directwebremoting.guice.DwrGuiceUtil.getInjector;
40 import static org.directwebremoting.guice.DwrGuiceUtil.popServletContext;
41 import static org.directwebremoting.guice.DwrGuiceUtil.pushServletContext;
42 import static org.directwebremoting.guice.ParamName.*;
43 import static org.directwebremoting.impl.ContainerUtil.INIT_CUSTOM_CONFIGURATOR;
44
45 /**
46  * An extension of the basic
47  * {@link org.directwebremoting.servlet.DwrServlet DwrServlet}
48  * that configures itself for dependency injection with Guice.
49  * Must be used in conjunction with
50  * {@link org.directwebremoting.guice.DwrGuiceServletContextFilter DwrGuiceServletContextFilter}.
51  * @author Tim Peierls [tim at peierls dot net]
52  */
53 public class DwrGuiceServlet extends DwrServlet
54 {
55     /**
56      * Copies DWR configuration values from the Guice bindings into
57      * {@code servletConfig} to make these values accessible to the
58      * standard DWR servlet configuration machinery.
59      */
60     @Override JavaDoc public void init(ServletConfig JavaDoc servletConfig) throws ServletException JavaDoc
61     {
62         // Save this for later use by destroy.
63 this.servletContext = servletConfig.getServletContext();
64         
65         // Set the current context thread-locally so our internal classes can
66 // look up the Injector and use it in turn to look up further objects.
67 pushServletContext(this.servletContext);
68         try
69         {
70             // Since ServletConfig is immutable, we use a modifiable
71 // decoration of the real servlet configuration and pass
72 // that to the init method of the superclass.
73 ModifiableServletConfig config = new ModifiableServletConfig(servletConfig);
74         
75             // Apply settings configured at bind-time.
76 setInitParameters(config);
77
78             // Use our internal manager classes to replace and delegate to
79 // any user-specified or default implementations, after adding
80 // additional creators and converters registered at bind-time.
81 configureDelegatedTypes(config);
82             
83             // Normal DwrServlet initialization happens here using the
84 // modified ServletConfig instead of the one we were passed.
85 super.init(config);
86
87             // Objects with (non-global) application scope are initialized
88 // eagerly.
89 initApplicationScoped();
90         }
91         finally
92         {
93             // Clean up the ThreadLocal we just used.
94 popServletContext();
95         }
96     }
97     
98     /**
99      * Closes any {@code Closeable} application-scoped objects.
100      * IO exceptions are collected but ignored.
101      */
102     @Override JavaDoc public void destroy()
103     {
104         pushServletContext(this.servletContext);
105         try
106         {
107             // Closeable objects with (non-global) application scope are closed.
108 List JavaDoc<Exception JavaDoc> exceptions = destroyApplicationScoped();
109             
110             super.destroy();
111             
112             for (Exception JavaDoc ex : exceptions)
113             {
114                 log.warn("During servlet shutdown", ex);
115             }
116         }
117         finally
118         {
119             popServletContext();
120             this.servletContext = null;
121         }
122     }
123     
124     /**
125      * Inject some values that might have been configured at bind-time.
126      * Override web.xml <init-param> settings in each case that injection
127      * is successful.
128      */
129     private void setInitParameters(ModifiableServletConfig config)
130     {
131         Injector injector = getInjector();
132         InjectedConfig cfg = new InjectedConfig(config);
133         injector.injectMembers(cfg);
134         cfg.setParameters();
135     }
136     
137     private static class InjectedConfig
138     {
139         InjectedConfig(ModifiableServletConfig config)
140         {
141             this.config = config;
142         }
143         
144         void setParameter(ParamName paramName, Object JavaDoc value)
145         {
146             if (value != null)
147             {
148                 config.setInitParameter(paramName.getName(), value.toString());
149             }
150         }
151         
152         void setParameters()
153         {
154             setParameter(ALLOW_GET_FOR_SAFARI, allowGetForSafariButMakeForgeryEasier);
155             setParameter(CROSS_DOMAIN_SESSION_SECURITY, crossDomainSessionSecurity);
156             setParameter(ALLOW_SCRIPT_TAG_REMOTING, allowScriptTagRemoting);
157             setParameter(DEBUG, debug);
158             setParameter(SCRIPT_SESSION_TIMEOUT, scriptSessionTimeout);
159             setParameter(MAX_CALL_COUNT, maxCallCount);
160             setParameter(ACTIVE_REVERSE_AJAX_ENABLED, activeReverseAjaxEnabled);
161             setParameter(MAX_WAIT_AFTER_WRITE, maxWaitAfterWrite);
162             setParameter(DISCONNECTED_TIME, disconnectedTime);
163             setParameter(POLL_AND_COMET_ENABLED, pollAndCometEnabled);
164             setParameter(MAX_WAITING_THREADS, maxWaitingThreads);
165             setParameter(MAX_POLL_HITS_PER_SECOND, maxPollHitsPerSecond);
166             setParameter(PRE_STREAM_WAIT_TIME, preStreamWaitTime);
167             setParameter(POST_STREAM_WAIT_TIME, postStreamWaitTime);
168             setParameter(IGNORE_LAST_MODIFIED, ignoreLastModified);
169             setParameter(SCRIPT_COMPRESSED, scriptCompressed);
170             setParameter(SESSION_COOKIE_NAME, sessionCookieName);
171             setParameter(WELCOME_FILES, welcomeFiles);
172             setParameter(NORMALIZE_INCLUDES_QUERY_STRING, normalizeIncludesQueryString);
173             setParameter(OVERRIDE_PATH, overridePath);
174
175             if (configurator != null)
176             {
177                 // InternalConfigurator knows how to look up the configurator
178 // instance again and delegate to it.
179 config.setInitParameter(INIT_CUSTOM_CONFIGURATOR, InternalConfigurator.class.getName());
180             }
181
182             if (classes != null)
183             {
184                 config.setInitParameter(CLASSES.getName(), classListToString(classes));
185             }
186         }
187         
188         @Inject(optional=true) @InitParam(ALLOW_GET_FOR_SAFARI) Boolean JavaDoc allowGetForSafariButMakeForgeryEasier = null;
189         @Inject(optional=true) @InitParam(CROSS_DOMAIN_SESSION_SECURITY) Boolean JavaDoc crossDomainSessionSecurity = null;
190         @Inject(optional=true) @InitParam(ALLOW_SCRIPT_TAG_REMOTING) Boolean JavaDoc allowScriptTagRemoting = null;
191         @Inject(optional=true) @InitParam(DEBUG) Boolean JavaDoc debug = null;
192         @Inject(optional=true) @InitParam(SCRIPT_SESSION_TIMEOUT) Long JavaDoc scriptSessionTimeout = null;
193         @Inject(optional=true) @InitParam(MAX_CALL_COUNT) Integer JavaDoc maxCallCount = null;
194         @Inject(optional=true) @InitParam(ACTIVE_REVERSE_AJAX_ENABLED) Boolean JavaDoc activeReverseAjaxEnabled = null;
195         @Inject(optional=true) @InitParam(MAX_WAIT_AFTER_WRITE) Long JavaDoc maxWaitAfterWrite = null;
196         @Inject(optional=true) @InitParam(DISCONNECTED_TIME) Long JavaDoc disconnectedTime = null;
197         @Inject(optional=true) @InitParam(POLL_AND_COMET_ENABLED) Boolean JavaDoc pollAndCometEnabled = null;
198         @Inject(optional=true) @InitParam(MAX_WAITING_THREADS) Integer JavaDoc maxWaitingThreads = null;
199         @Inject(optional=true) @InitParam(MAX_POLL_HITS_PER_SECOND) Integer JavaDoc maxPollHitsPerSecond = null;
200         @Inject(optional=true) @InitParam(PRE_STREAM_WAIT_TIME) Long JavaDoc preStreamWaitTime = null;
201         @Inject(optional=true) @InitParam(POST_STREAM_WAIT_TIME) Long JavaDoc postStreamWaitTime = null;
202         @Inject(optional=true) @InitParam(IGNORE_LAST_MODIFIED) Boolean JavaDoc ignoreLastModified = null;
203         @Inject(optional=true) @InitParam(SCRIPT_COMPRESSED) Boolean JavaDoc scriptCompressed = null;
204         @Inject(optional=true) @InitParam(SESSION_COOKIE_NAME) String JavaDoc sessionCookieName = null;
205         @Inject(optional=true) @InitParam(WELCOME_FILES) String JavaDoc welcomeFiles = null;
206         @Inject(optional=true) @InitParam(NORMALIZE_INCLUDES_QUERY_STRING) Boolean JavaDoc normalizeIncludesQueryString = null;
207         @Inject(optional=true) @InitParam(OVERRIDE_PATH) String JavaDoc overridePath = null;
208         
209         @Inject(optional=true) Configurator configurator = null;
210         
211         @Inject(optional=true) @InitParam(CLASSES) List JavaDoc<Class JavaDoc> classes = null;
212         
213         private final ModifiableServletConfig config;
214     }
215     
216
217     private void configureDelegatedTypes(ModifiableServletConfig config)
218     {
219         // Get the user-specified type names, if any, for CreatorManager
220 // and ConverterManager and stash them (thread-locally) so that
221 // InternalCreatorManager and InternalConverterManager can retrieve
222 // them in their parameterless constructors.
223
224         InternalCreatorManager.setTypeName(config.getInitParameter(INIT_CREATOR_MANAGER));
225         InternalConverterManager.setTypeName(config.getInitParameter(INIT_CONVERTER_MANAGER));
226         InternalAjaxFilterManager.setTypeName(config.getInitParameter(INIT_AJAX_FILTER_MANAGER));
227         
228         // Tell DWR to use our special delegating classes that know how to
229 // create delegates of the appropriate type by looking at the type
230 // names that we just stashed.
231
232         config.setInitParameter(INIT_CREATOR_MANAGER, InternalCreatorManager.class.getName());
233         config.setInitParameter(INIT_CONVERTER_MANAGER, InternalConverterManager.class.getName());
234         config.setInitParameter(INIT_AJAX_FILTER_MANAGER, InternalAjaxFilterManager.class.getName());
235     }
236     
237     
238     private static void initApplicationScoped()
239     {
240         Injector injector = getInjector();
241         for (Key<?> key : DwrScopes.APPLICATION.getKeysInScope())
242         {
243             // Eagerly create application-scoped object.
244 injector.getInstance(key);
245         }
246     }
247     
248     private static List JavaDoc<Exception JavaDoc> destroyApplicationScoped()
249     {
250         final List JavaDoc<Exception JavaDoc> exceptions = new ArrayList JavaDoc<Exception JavaDoc>();
251         DwrScopes.APPLICATION.closeAll(new ExceptionLoggingCloseableHandler(exceptions));
252         return exceptions;
253     }
254
255
256     static String JavaDoc classListToString(List JavaDoc<Class JavaDoc> classList)
257     {
258         StringBuilder JavaDoc buf = new StringBuilder JavaDoc();
259         int count = 0;
260         for (Class JavaDoc cls : classList)
261         {
262             if (count++ > 0) buf.append(", ");
263             buf.append(cls.getName());
264         }
265         return buf.toString();
266     }
267
268     
269     /**
270      * Used to stash context for later use by destroy().
271      */
272     private volatile ServletContext JavaDoc servletContext;
273     
274     
275     /**
276      * The name DWR uses to look up a CreatorManager implementation class name
277      */
278     private static final String JavaDoc INIT_CREATOR_MANAGER = CreatorManager.class.getName();
279     
280     /**
281      * The name DWR uses to look up a ConverterManager implementation class name
282      */
283     private static final String JavaDoc INIT_CONVERTER_MANAGER = ConverterManager.class.getName();
284     
285     /**
286      * The name DWR uses to look up an AjaxFilterManager implementation class name
287      */
288     private static final String JavaDoc INIT_AJAX_FILTER_MANAGER = AjaxFilterManager.class.getName();
289
290     /**
291      * The log stream
292      */
293     private static final Logger log = Logger.getLogger(DwrGuiceServlet.class);
294 }
295
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