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Java > Open Source Codes > org > apache > struts > chain > CreateActionForm


1 /*
2  * Copyright 2003,2004 The Apache Software Foundation.
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
17 package org.apache.struts.chain;
18
19
20 import org.apache.commons.beanutils.DynaBean;
21 import org.apache.commons.chain.Command;
22 import org.apache.commons.chain.Context;
23 import org.apache.commons.chain.web.WebContext;
24 import org.apache.struts.action.ActionForm;
25 import org.apache.struts.action.ActionMapping;
26 import org.apache.struts.action.ActionServlet;
27 import org.apache.struts.action.DynaActionForm;
28 import org.apache.struts.action.DynaActionFormClass;
29 import org.apache.struts.chain.Constants;
30 import org.apache.struts.chain.util.ClassUtils;
31 import org.apache.struts.config.ActionConfig;
32 import org.apache.struts.config.FormBeanConfig;
33 import org.apache.struts.config.ModuleConfig;
34 import org.apache.commons.logging.Log;
35 import org.apache.commons.logging.LogFactory;
36
37
38 /**
39  * <p>Create (if necessary) and cache a form bean for this request.</p>
40  *
41  * @author Craig R. McClanahan
42  * @version $Rev: 54933 $ $Date: 2004-10-16 18:04:52 +0100 (Sat, 16 Oct 2004) $
43  */
44
45 public class CreateActionForm implements Command {
46
47
48     // ------------------------------------------------------ Instance Variables
49
50
51     private String JavaDoc actionConfigKey = Constants.ACTION_CONFIG_KEY;
52     private String JavaDoc actionFormKey = Constants.ACTION_FORM_KEY;
53     private String JavaDoc actionServletKey = Constants.ACTION_SERVLET_KEY;
54     private String JavaDoc moduleConfigKey = Constants.MODULE_CONFIG_KEY;
55
56     private static final Log log =
57         LogFactory.getLog(CreateActionForm.class);
58
59     // -------------------------------------------------------------- Properties
60
61
62     /**
63      * <p>Return the context attribute key under which the
64      * <code>ActionConfig</code> for the currently selected application
65      * action is stored.</p>
66      */
67     public String JavaDoc getActionConfigKey() {
68
69         return (this.actionConfigKey);
70
71     }
72
73
74     /**
75      * <p>Set the context attribute key under which the
76      * <code>ActionConfig</code> for the currently selected application
77      * action is stored.</p>
78      *
79      * @param actionConfigKey The new context attribute key
80      */
81     public void setActionConfigKey(String JavaDoc actionConfigKey) {
82
83         this.actionConfigKey = actionConfigKey;
84
85     }
86
87
88     /**
89      * <p>Return the context attribute key under which the
90      * <code>ActionForm</code> for the currently selected application
91      * action is stored.</p>
92      */
93     public String JavaDoc getActionFormKey() {
94
95         return (this.actionFormKey);
96
97     }
98
99
100     /**
101      * <p>Set the context attribute key under which the
102      * <code>ActionForm</code> for the currently selected application
103      * action is stored.</p>
104      *
105      * @param actionFormKey The new context attribute key
106      */
107     public void setActionFormKey(String JavaDoc actionFormKey) {
108
109         this.actionFormKey = actionFormKey;
110
111     }
112
113
114     /**
115      * <p>Return the context attribute key under which the
116      * <code>ActionServlet</code> for the currently selected application
117      * action is stored.</p>
118      */
119     public String JavaDoc getActionServletKey() {
120
121         return (this.actionServletKey);
122
123     }
124
125
126     /**
127      * <p>Set the context attribute key under which the
128      * <code>ActionServlet</code> for the currently selected application
129      * action is stored.</p>
130      *
131      * @param actionServletKey The new context attribute key
132      */
133     public void setActionServletKey(String JavaDoc actionServletKey) {
134
135         this.actionServletKey = actionServletKey;
136
137     }
138     
139     /**
140      * <p>Return the context attribute key under which the
141      * <code>ModuleConfig</code> for the currently selected application
142      * module is stored.</p>
143      */
144     public String JavaDoc getModuleConfigKey() {
145
146         return (this.moduleConfigKey);
147
148     }
149
150
151     /**
152      * <p>Set the context attribute key under which the
153      * <code>ModuleConfig</code> for the currently selected application
154      * module is stored.</p>
155      *
156      * @param moduleConfigKey The new context attribute key
157      */
158     public void setModuleConfigKey(String JavaDoc moduleConfigKey) {
159
160         this.moduleConfigKey = moduleConfigKey;
161
162     }
163
164
165     // ---------------------------------------------------------- Public Methods
166
167
168     /**
169      * <p>Create (if necessary) and cache a form bean for this request.</p>
170      *
171      * @param context The <code>Context</code> for the current request
172      *
173      * @return <code>false</code> so that processing continues
174      */
175     public boolean execute(Context context) throws Exception JavaDoc {
176
177         // Is there a form bean associated with this ActionConfig?
178 ActionConfig actionConfig = (ActionConfig)
179             context.get(getActionConfigKey());
180         String JavaDoc name = actionConfig.getName();
181         if (name == null) {
182             context.remove(getActionFormKey());
183             return (false);
184         }
185
186         log.trace("Look up form-bean " + name);
187
188         // Look up the corresponding FormBeanConfig (if any)
189 FormBeanConfig formBeanConfig =
190             actionConfig.getModuleConfig().findFormBeanConfig(name);
191         if (formBeanConfig == null) {
192             log.warn("No FormBeanConfig found in module "
193                      + actionConfig.getModuleConfig().getPrefix()
194                      + " under name " + name);
195             context.remove(getActionFormKey());
196             return (false);
197         }
198
199         // Look up the session scope ActionForm instance (if any)
200 WebContext wcontext = (WebContext) context;
201         ActionForm instance = null;
202         if ("session".equals(actionConfig.getScope())) {
203             instance = (ActionForm)
204                 wcontext.getSessionScope().get(actionConfig.getAttribute());
205         }
206
207         // Can we recycle the existing instance (if any)?
208 if (instance != null) {
209             log.trace("Found an instance in the session; test for reusability");
210             if (formBeanConfig.getDynamic()) {
211                 String JavaDoc className =
212                     ((DynaBean) instance).getDynaClass().getName();
213                 if (className.equals(formBeanConfig.getName())) {
214                     wcontext.put
215                         (getActionFormKey(), instance);
216                     /* It should already be in session scope
217                     if ("session".equals(actionConfig.getScope())) {
218                         wcontext.getSessionScope().put
219                             (actionConfig.getAttribute(), instance);
220                     }
221                     */
222                     log.debug("Using existing instance (dynamic)");
223                     return (false);
224                 }
225             } else {
226                 try {
227                     Class JavaDoc configClass =
228                         ClassUtils.getApplicationClass
229                         (formBeanConfig.getType());
230                     if (configClass.isAssignableFrom(instance.getClass())) {
231                         wcontext.put
232                             (getActionFormKey(), instance);
233                         /* It should already be in session scope
234                            if ("session".equals(actionConfig.getScope())) {
235                            wcontext.getSessionScope().put
236                            (actionConfig.getAttribute(), instance);
237                            }
238                         */
239                         log.debug("Using existing instance (non-dynamic)");
240                         return (false);
241                     }
242                 } catch (Exception JavaDoc e) {
243                     log.debug("Error testing existing instance for reusability; just create a new instance", e);
244                 }
245             }
246         }
247
248         log.trace("Make a new instance of: " + formBeanConfig);
249         // Create a new form bean instance
250 if (formBeanConfig.getDynamic()) {
251             ModuleConfig moduleConfig = (ModuleConfig)
252                 wcontext.get(getModuleConfigKey());
253             DynaActionFormClass dynaClass =
254                 DynaActionFormClass.createDynaActionFormClass(formBeanConfig);
255             instance = (ActionForm) dynaClass.newInstance();
256             ((DynaActionForm) instance).initialize
257                 ((ActionMapping) actionConfig);
258         } else {
259             instance = (ActionForm)
260                 ClassUtils.getApplicationInstance(formBeanConfig.getType());
261         }
262
263         // Configure and cache the new instance
264 ActionServlet servlet = (ActionServlet)
265             wcontext.get(getActionServletKey());
266         instance.setServlet(servlet);
267         wcontext.put(getActionFormKey(), instance);
268         if ("session".equals(actionConfig.getScope())) {
269             wcontext.getSessionScope().put
270                 (actionConfig.getAttribute(), instance);
271         } else if ("request".equals(actionConfig.getScope())) {
272             wcontext.getRequestScope().put
273                 (actionConfig.getAttribute(), instance);
274         }
275
276         return (false);
277
278     }
279
280
281 }
282
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