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1   /*
2    * $Id: DynaActionFormClass.java 421119 2006-07-12 04:49:11Z wsmoak $
3    *
4    * Copyright 2000-2004 The Apache Software Foundation.
5    *
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * You may obtain a copy of the License at
9    *
10   *      http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.struts.action;
19  
20  import org.apache.commons.beanutils.DynaBean;
21  import org.apache.commons.beanutils.DynaClass;
22  import org.apache.commons.beanutils.DynaProperty;
23  import org.apache.struts.config.FormBeanConfig;
24  import org.apache.struts.config.FormPropertyConfig;
25  import org.apache.struts.util.RequestUtils;
26  
27  import java.io.Serializable;
28  
29  import java.util.HashMap;
30  
31  /***
32   * <p>Implementation of <code>DynaClass</code> for <code>DynaActionForm</code>
33   * classes that allow developers to define ActionForms without having to
34   * individually code all of the classes. <strong>NOTE</strong> - This class is
35   * only used in the internal implementation of dynamic action form beans.
36   * Application developers never need to consult this documentation.</p>
37   *
38   * @version $Rev: 421119 $ $Date: 2006-01-17 07:26:20 -0500 (Tue, 17 Jan 2006)
39   *          $
40   * @since Struts 1.1
41   */
42  public class DynaActionFormClass implements DynaClass, Serializable {
43      // ----------------------------------------------------- Instance Variables
44  
45      /***
46       * <p>The <code>DynaActionForm</code> implementation <code>Class</code>
47       * which we will use to create new bean instances.</p>
48       */
49      protected transient Class beanClass = null;
50  
51      /***
52       * <p>The form bean configuration information for this class.</p>
53       */
54      protected FormBeanConfig config = null;
55  
56      /***
57       * <p>The "dynamic class name" for this <code>DynaClass</code>.</p>
58       */
59      protected String name = null;
60  
61      /***
62       * <p>The set of dynamic properties that are part of this DynaClass.</p>
63       */
64      protected DynaProperty[] properties = null;
65  
66      /***
67       * <p>The set of dynamic properties that are part of this
68       * <code>DynaClass</code>, keyed by the property name.  Individual
69       * descriptor instances will be the same instances as those in the
70       * <code>properties</code> list.
71       */
72      protected HashMap propertiesMap = new HashMap();
73  
74      // ----------------------------------------------------------- Constructors
75  
76      /***
77       * <p>Construct a new <code>DynaActionFormClass</code> for the specified
78       * form bean configuration.  This constructor is private;
79       * <code>DynaActionFormClass</code> instances will be created as needed
80       * via calls to the static <code>createDynaActionFormClass()</code>
81       * method.</p>
82       *
83       * @param config The FormBeanConfig instance describing the properties of
84       *               the bean to be created
85       * @throws IllegalArgumentException if the bean implementation class
86       *                                  specified in the configuration is not
87       *                                  DynaActionForm (or a subclass of
88       *                                  DynaActionForm)
89       */
90      public DynaActionFormClass(FormBeanConfig config) {
91          introspect(config);
92      }
93  
94      // ------------------------------------------------------ DynaClass Methods
95  
96      /***
97       * <p>Return the name of this <code>DynaClass</code> (analogous to the
98       * <code>getName()</code> method of <code>java.lang.Class</code>, which
99       * allows the same <code>DynaClass</code> implementation class to support
100      * different dynamic classes, with different sets of properties.
101      *
102      * @return The name of this <code>DynaClass</code>.
103      */
104     public String getName() {
105         return (this.name);
106     }
107 
108     /***
109      * <p>Return a property descriptor for the specified property, if it
110      * exists; otherwise, return <code>null</code>.</p>
111      *
112      * @param name Name of the dynamic property for which a descriptor is
113      *             requested
114      * @return A property descriptor for the specified property.
115      * @throws IllegalArgumentException if no property name is specified
116      */
117     public DynaProperty getDynaProperty(String name) {
118         if (name == null) {
119             throw new IllegalArgumentException("No property name specified");
120         }
121 
122         return ((DynaProperty) propertiesMap.get(name));
123     }
124 
125     /***
126      * <p>Return an array of <code>DynaProperty</code>s for the properties
127      * currently defined in this <code>DynaClass</code>.  If no properties are
128      * defined, a zero-length array will be returned.</p>
129      *
130      * @return An array of property instances for this class.
131      */
132     public DynaProperty[] getDynaProperties() {
133         return (properties);
134 
135         // :FIXME: Should we really be implementing
136         // getBeanInfo instead, which returns property descriptors
137         // and a bunch of other stuff?
138     }
139 
140     /***
141      * <p>Instantiate and return a new {@link DynaActionForm} instance,
142      * associated with this <code>DynaActionFormClass</code>.  The properties
143      * of the returned {@link DynaActionForm} will have been initialized to
144      * the default values specified in the form bean configuration
145      * information.</p>
146      *
147      * @return A new {@link DynaActionForm} instance.
148      * @throws IllegalAccessException if the Class or the appropriate
149      *                                constructor is not accessible
150      * @throws InstantiationException if this Class represents an abstract
151      *                                class, an array class, a primitive type,
152      *                                or void; or if instantiation fails for
153      *                                some other reason
154      */
155     public DynaBean newInstance()
156         throws IllegalAccessException, InstantiationException {
157         DynaActionForm dynaBean = (DynaActionForm) getBeanClass().newInstance();
158 
159         dynaBean.setDynaActionFormClass(this);
160 
161         FormPropertyConfig[] props = config.findFormPropertyConfigs();
162 
163         for (int i = 0; i < props.length; i++) {
164             dynaBean.set(props[i].getName(), props[i].initial());
165         }
166 
167         return (dynaBean);
168     }
169 
170     // --------------------------------------------------------- Public Methods
171 
172     /***
173      * <p>Render a <code>String</code> representation of this object.</p>
174      *
175      * @return The string representation of this instance.
176      */
177     public String toString() {
178         StringBuffer sb = new StringBuffer("DynaActionFormBean[name=");
179 
180         sb.append(name);
181 
182         DynaProperty[] props = getDynaProperties();
183 
184         if (props == null) {
185             props = new DynaProperty[0];
186         }
187 
188         for (int i = 0; i < props.length; i++) {
189             sb.append(',');
190             sb.append(props[i].getName());
191             sb.append('/');
192             sb.append(props[i].getType());
193         }
194 
195         sb.append("]");
196 
197         return (sb.toString());
198     }
199 
200     // --------------------------------------------------------- Static Methods
201 
202     /***
203      * Return the <code>DynaActionFormClass</code> instance for the specified
204      * form bean configuration instance.
205      *
206      * @param config The config for which the class should be created.
207      * @return The instance for the specified form bean config.
208      */
209     public static DynaActionFormClass createDynaActionFormClass(
210         FormBeanConfig config) {
211         return config.getDynaActionFormClass();
212     }
213 
214     // ------------------------------------------------------ Protected Methods
215 
216     /***
217      * <p>Return the implementation class we are using to construct new
218      * instances, re-introspecting our {@link FormBeanConfig} if necessary
219      * (that is, after being deserialized, since <code>beanClass</code> is
220      * marked transient).</p>
221      *
222      * @return The implementation class used to construct new instances.
223      */
224     protected Class getBeanClass() {
225         if (beanClass == null) {
226             introspect(config);
227         }
228 
229         return (beanClass);
230     }
231 
232     /***
233      * <p>Introspect our form bean configuration to identify the supported
234      * properties.</p>
235      *
236      * @param config The FormBeanConfig instance describing the properties of
237      *               the bean to be created
238      * @throws IllegalArgumentException if the bean implementation class
239      *                                  specified in the configuration is not
240      *                                  DynaActionForm (or a subclass of
241      *                                  DynaActionForm)
242      */
243     protected void introspect(FormBeanConfig config) {
244         this.config = config;
245 
246         // Validate the ActionFormBean implementation class
247         try {
248             beanClass = RequestUtils.applicationClass(config.getType());
249         } catch (Throwable t) {
250             throw new IllegalArgumentException(
251                 "Cannot instantiate ActionFormBean class '" + config.getType()
252                 + "': " + t);
253         }
254 
255         if (!DynaActionForm.class.isAssignableFrom(beanClass)) {
256             throw new IllegalArgumentException("Class '" + config.getType()
257                 + "' is not a subclass of "
258                 + "'org.apache.struts.action.DynaActionForm'");
259         }
260 
261         // Set the name we will know ourselves by from the form bean name
262         this.name = config.getName();
263 
264         // Look up the property descriptors for this bean class
265         FormPropertyConfig[] descriptors = config.findFormPropertyConfigs();
266 
267         if (descriptors == null) {
268             descriptors = new FormPropertyConfig[0];
269         }
270 
271         // Create corresponding dynamic property definitions
272         properties = new DynaProperty[descriptors.length];
273 
274         for (int i = 0; i < descriptors.length; i++) {
275             properties[i] =
276                 new DynaProperty(descriptors[i].getName(),
277                     descriptors[i].getTypeClass());
278             propertiesMap.put(properties[i].getName(), properties[i]);
279         }
280     }
281 
282     // -------------------------------------------------------- Private Methods
283 }