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Java > Open Source Codes > com > jcorporate > expresso > core > controller > DynamicForwarder


1 /* ====================================================================
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64
65 package com.jcorporate.expresso.core.controller;
66
67 import com.jcorporate.expresso.core.ExpressoConstants;
68 import com.jcorporate.expresso.core.jsdkapi.GenericSession;
69 import org.apache.struts.config.ForwardConfig;
70
71 import javax.servlet.ServletException JavaDoc;
72 import javax.servlet.http.HttpServletRequest JavaDoc;
73 import java.io.Serializable JavaDoc;
74 import java.util.HashMap JavaDoc;
75 import java.util.Map JavaDoc;
76
77 /**
78  * Used for custom dynamic routing. Specify the pageStyle parameter before calling
79  * a struts-based controller and the RequestProcessor will pick it up at forward
80  * time.
81  *
82  * @author Michael Rimov
83  */
84
85 public class DynamicForwarder implements Serializable JavaDoc {
86 // private static final Logger log = Logger.getLogger(DynamicForwarder.class);
87
88     /**
89      * A map of session forward objects
90      */
91     Map JavaDoc sessionForwards = new HashMap JavaDoc();
92
93     /**
94      * Object lock to prevent multiple creations
95      */
96     private static final Object JavaDoc objectLock = new Object JavaDoc();
97
98     /**
99      * Do not call directly
100      */
101     protected DynamicForwarder() {
102
103     }
104
105     /**
106      * Add's a forward config to the session as defined by 'pageStyle'
107      *
108      * @param pageStyle the key for the forward config
109      * @param servletRequest the servlet request object
110      * @param forwardConfig the actual forward object
111      * @throws ServletException upon error saving the object to the session.
112      */
113     public static void addConfig(String JavaDoc pageStyle,
114                                  HttpServletRequest JavaDoc servletRequest,
115                                  ForwardConfig forwardConfig) throws ServletException JavaDoc {
116         synchronized (objectLock) {
117             DynamicForwarder forwarder = (DynamicForwarder) GenericSession
118                     .getAttribute(servletRequest, ExpressoConstants
119                     .PROCESSOR_FORWARD_KEY);
120             if (forwarder == null) {
121
122                 forwarder = new DynamicForwarder();
123                 GenericSession.setAttribute(servletRequest,
124                         ExpressoConstants.PROCESSOR_FORWARD_KEY
125                         , forwarder);
126             }
127
128             forwarder.sessionForwards.put(pageStyle
129                     , forwardConfig);
130         }
131     }
132
133     /**
134      * Redeem the configuration. IF it doesn't exist then we return null. If it
135      * DOES exist, then we remove it from the session
136      *
137      * @param pageStyle the page style to redeeem
138      * @param servletRequest the servletRequest object
139      * @return a ForwardConfig or null if none exists in the session
140      * @throws ServletException upon error retrieving the object from the session
141      */
142     public static synchronized ForwardConfig redeemConfig(String JavaDoc pageStyle,
143                                                           HttpServletRequest JavaDoc servletRequest) throws ServletException JavaDoc {
144         synchronized (objectLock) {
145             DynamicForwarder forwarder = (DynamicForwarder) GenericSession
146                     .getAttribute(servletRequest, ExpressoConstants
147                     .PROCESSOR_FORWARD_KEY);
148             if (forwarder == null) {
149                 return null;
150             }
151
152             ForwardConfig fc;
153             fc = (ForwardConfig) forwarder.sessionForwards.get(pageStyle);
154             if (fc != null) {
155                 forwarder.sessionForwards.remove(pageStyle);
156             }
157             return fc;
158         }
159     }
160 }
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