WebAppUtil


1   /**
2    * Copyright 2003-2006 the original author or authors.
3    * Licensed under the Apache License, Version 2.0 (the "License");
4    * you may not use this file except in compliance with the License.
5    * You may obtain a copy of the License at
6   
7    http://www.apache.org/licenses/LICENSE-2.0
8   
9    * Unless required by applicable law or agreed to in writing, software
10   * distributed under the License is distributed on an "AS IS" BASIS,
11   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12   * See the License for the specific language governing permissions and
13   * limitations under the License.
14   */
15  
16  package com.jdon.controller;
17  
18  import javax.servlet.ServletContext  ;
19  import javax.servlet.http.HttpServletRequest  ;
20  
21  import org.aopalliance.intercept.MethodInterceptor;
22  
23  import com.jdon.aop.interceptor.InterceptorsChain;
24  import com.jdon.aop.joinpoint.Pointcut;
25  import com.jdon.bussinessproxy.TargetMetaDef;
26  import com.jdon.bussinessproxy.meta.MethodMetaArgs;
27  import com.jdon.container.ContainerWrapper;
28  import com.jdon.container.builder.ContainerBuilder;
29  import com.jdon.container.finder.ComponentKeys;
30  import com.jdon.container.finder.ServletContainerFinder;
31  import com.jdon.controller.events.EventModel;
32  import com.jdon.controller.model.ModelIF;
33  import com.jdon.controller.service.Service;
34  import com.jdon.controller.service.ServiceFacade;
35  import com.jdon.controller.service.ServiceFactory;
36  import com.jdon.model.handler.HandlerMethodMetaArgsFactory;
37  import com.jdon.util.Debug;
38  
39  /**
40   * Using WebAppUtil, framework's user can get his businesss service object that
41   * defined in jdonframework.xml
42   * 
43   * this is main and important client class for framework's user.
44   * 
45   * 
46   * @author banq
47   */
48  public class WebAppUtil {
49      private final static String   module = WebAppUtil.class.getName();
50  
51      private final static ServletContainerFinder scf = new ServletContainerFinder();
52  
53      /**
54       * get a service from jdonframework.xml's service configure. the service
55       * maybe is a pojo service or a ejb service.
56       * 
57       * <p>if user has a business interface, so the interface can has two
58       * implemention:pojo or ejb, if is ejb, the ejb's local/remote interface
59       * must inherit the business interface. so the application's MVC will
60       * completely seperate from his business lay
61       * 
62       * <p>usage: in jdonframework.xml: <pojoService name="userJdbcDao"
63       * class="news.container.UserJdbcDao"> <constructor value="java:/NewsDS"/>
64       * </pojoService>
65       * 
66       * <p>UserDao ud = (UserDao)WebAppUtil.getService(“userJdbcDao�?, request);
67       * 
68       * UserDao is a interface.
69       * 
70       * @param name String
71       * @param request HttpServletRequest
72       * @return Object
73       * @throws Exception
74       */
75      public static Object   getService(String   name, HttpServletRequest   request) {
76          ServiceFacade serviceFacade = new ServiceFacade();
77          ServiceFactory serviceFactory = serviceFacade.getServiceFactory(request);
78          return serviceFactory.getService(name, request);
79      }
80  
81      public static Object   getService(TargetMetaDef targetMetaDef, HttpServletRequest   request) {
82          ServiceFacade serviceFacade = new ServiceFacade();
83          ServiceFactory serviceFactory = serviceFacade.getServiceFactory(request);
84          return serviceFactory.getService(targetMetaDef, request);
85      }
86  
87      /**
88       * get a component that registered in container. the component is not
89       * different from the service.
90       * 
91       * the component instance is single instance
92       * 
93       */
94      public static Object   getComponentInstance(String   name, HttpServletRequest   request) {
95          ContainerWrapper containerWrapper = scf.findContainer(request);
96          return containerWrapper.lookup(name);
97      }
98  
99      public static Object   getComponentInstance(String   name, ServletContext   sc) {
100         ContainerWrapper containerWrapper = scf.findContainer(sc);
101         return containerWrapper.lookup(name);
102     }
103 
104     /**
105      * get a EJB service directly.
106      * 
107      * @param name  String
108      * @param request HttpServletRequest
109      * @return Object
110      * @throws Exception
111      */
112     public static Object   getEJBService(String   name, HttpServletRequest   request) throws Exception   {
113         return getService(name, request);
114     }
115 
116     /**
117      * Command pattern for service invoke
118      * sample:
119      * browser url: /aaa.do?method=xxxxx 
120      * 
121      * xxxxx is the service's method, such as:
122      * 
123      * public interface TestService{
124      *  　　 void xxxxx(EventModel em);　　 
125      * }
126      * @see com.jdon.strutsutil.ServiceMethodAction
127      * 
128      * @param serviceName the service name in jdonframework.xml
129      * @param methodName  the method name
130      * @param request
131      * @param model       the method parameter must be packed in a ModelIF object.
132      *                    if no method parameter, set it to null;
133      * @return            return the service dealing result
134      * @throws Exception
135      * 
136      */
137     public static Object   callService(String   serviceName, String   methodName, Object  [] methodParams, HttpServletRequest   request) throws Exception   {
138         Debug.logVerbose("[JdonFramework] call the method: " + methodName + " for the service: " + serviceName, module);
139         Object   result = null;
140         try {
141             HandlerMethodMetaArgsFactory maFactory = new HandlerMethodMetaArgsFactory();                        
142             MethodMetaArgs methodMetaArgs = maFactory.createDirectMethod(methodName, methodParams);
143 
144             ServiceFacade serviceFacade = new ServiceFacade();
145             Service service = serviceFacade.getService(request);
146             result = service.execute(serviceName, methodMetaArgs, request);
147         } catch (Exception   ex) {
148             Debug.logError("[JdonFramework] serviceAction Error: " + ex, module);
149             throw new Exception  (" serviceAction Error:" + ex);
150         }
151         return result;
152     }
153    
154 
155     /**
156      * get the key for the application container user can directly get his
157      * container from servletcontext by the key.
158      * 
159      * @return String
160      */
161     public static String   getContainerKey() {
162         return ContainerBuilder.APPLICATION_CONTEXT_ATTRIBUTE_NAME;
163     }
164 
165     /**
166      * get the key for the interceptor, by the key, use can add his interceptor
167      * to the container
168      * 
169      * @return String
170      */
171     public static String   getInterceptorKey() {
172         return InterceptorsChain.NAME;
173     }
174 
175     /**
176      * get this Web application's container
177      * 
178      * @param request HttpServletRequest
179      * @return ContainerWrapper
180      * @throws Exception
181      */
182     public static ContainerWrapper getContainer(HttpServletRequest   request) throws Exception   {
183         ServletContainerFinder scf = new ServletContainerFinder();
184         return scf.findContainer(request);
185     }
186 
187     /**
188      * add a MethodInterceptor for all services how to implements a
189      * MethodInterceptor,reference:
190      * 
191      */
192     public static void addInterceptor(MethodInterceptor interceptor, HttpServletRequest   request) throws Exception   {
193         addInterceptor(Pointcut.TARGET_PROPS_SERVICES, interceptor, request);
194     }
195 
196     /**
197      * add a MethodInterceptor for pointcut
198      * 
199      * @param pointcut  Pointcut values
200      * @param interceptor
201      * @param request
202      * @throws Exception
203      */
204     public static void addInterceptor(String   pointcut, MethodInterceptor interceptor, HttpServletRequest   request) throws Exception   {
205         ContainerWrapper cw = getContainer(request);
206         if (cw == null) {
207             throw new Exception  ("Please at first init the JdonFramework!");
208         }
209         InterceptorsChain interceptorsChain = (InterceptorsChain) cw.lookup(ComponentKeys.INTERCEPTOR_CHAIN);
210         interceptorsChain.addInterceptor(pointcut, interceptor);
211     }
212 
213 }
214
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