ObjectCreateRule


1   /* $Id: ObjectCreateRule.java 467222 2006-10-24 03:17:11Z markt $
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one or more
4    * contributor license agreements.  See the NOTICE file distributed with
5    * this work for additional information regarding copyright ownership.
6    * The ASF licenses this file to You under the Apache License, Version 2.0
7    * (the "License"); you may not use this file except in compliance with
8    * the License.  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  
19  
20  package org.apache.tomcat.util.digester;
21  
22  
23  import org.xml.sax.Attributes  ;
24  
25  
26  /**
27   * Rule implementation that creates a new object and pushes it
28   * onto the object stack.  When the element is complete, the
29   * object will be popped
30   */
31  
32  public class ObjectCreateRule extends Rule {
33  
34  
35      // ----------------------------------------------------------- Constructors
36  
37  
38      /**
39       * Construct an object create rule with the specified class name.
40       *
41       * @param digester The associated Digester
42       * @param className Java class name of the object to be created
43       *
44       * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
45       * Use {@link #ObjectCreateRule(String className)} instead.
46       */
47      public ObjectCreateRule(Digester digester, String   className) {
48  
49          this(className);
50  
51      }
52  
53  
54      /**
55       * Construct an object create rule with the specified class.
56       *
57       * @param digester The associated Digester
58       * @param clazz Java class name of the object to be created
59       *
60       * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
61       * Use {@link #ObjectCreateRule(Class clazz)} instead.
62       */
63      public ObjectCreateRule(Digester digester, Class   clazz) {
64  
65          this(clazz);
66  
67      }
68  
69  
70      /**
71       * Construct an object create rule with the specified class name and an
72       * optional attribute name containing an override.
73       *
74       * @param digester The associated Digester
75       * @param className Java class name of the object to be created
76       * @param attributeName Attribute name which, if present, contains an
77       *  override of the class name to create
78       *
79       * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
80       * Use {@link #ObjectCreateRule(String className, String attributeName)} instead.
81       */
82      public ObjectCreateRule(Digester digester, String   className,
83                              String   attributeName) {
84  
85          this (className, attributeName);
86  
87      }
88  
89  
90      /**
91       * Construct an object create rule with the specified class and an
92       * optional attribute name containing an override.
93       *
94       * @param digester The associated Digester
95       * @param attributeName Attribute name which, if present, contains an
96       * @param clazz Java class name of the object to be created
97       *  override of the class name to create
98       *
99       * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
100      * Use {@link #ObjectCreateRule(String attributeName, Class clazz)} instead.
101      */
102     public ObjectCreateRule(Digester digester,
103                             String   attributeName,
104                             Class   clazz) {
105 
106         this(attributeName, clazz);
107 
108     }
109 
110     /**
111      * Construct an object create rule with the specified class name.
112      *
113      * @param className Java class name of the object to be created
114      */
115     public ObjectCreateRule(String   className) {
116 
117         this(className, (String  ) null);
118 
119     }
120 
121 
122     /**
123      * Construct an object create rule with the specified class.
124      *
125      * @param clazz Java class name of the object to be created
126      */
127     public ObjectCreateRule(Class   clazz) {
128 
129         this(clazz.getName(), (String  ) null);
130 
131     }
132 
133 
134     /**
135      * Construct an object create rule with the specified class name and an
136      * optional attribute name containing an override.
137      *
138      * @param className Java class name of the object to be created
139      * @param attributeName Attribute name which, if present, contains an
140      *  override of the class name to create
141      */
142     public ObjectCreateRule(String   className,
143                             String   attributeName) {
144 
145         this.className = className;
146         this.attributeName = attributeName;
147 
148     }
149 
150 
151     /**
152      * Construct an object create rule with the specified class and an
153      * optional attribute name containing an override.
154      *
155      * @param attributeName Attribute name which, if present, contains an
156      * @param clazz Java class name of the object to be created
157      *  override of the class name to create
158      */
159     public ObjectCreateRule(String   attributeName,
160                             Class   clazz) {
161 
162         this(clazz.getName(), attributeName);
163 
164     }
165 
166     // ----------------------------------------------------- Instance Variables
167 
168 
169     /**
170      * The attribute containing an override class name if it is present.
171      */
172     protected String   attributeName = null;
173 
174 
175     /**
176      * The Java class name of the object to be created.
177      */
178     protected String   className = null;
179 
180 
181     // --------------------------------------------------------- Public Methods
182 
183 
184     /**
185      * Process the beginning of this element.
186      *
187      * @param attributes The attribute list of this element
188      */
189     public void begin(Attributes   attributes) throws Exception   {
190 
191         // Identify the name of the class to instantiate
192         String   realClassName = className;
193         if (attributeName != null) {
194             String   value = attributes.getValue(attributeName);
195             if (value != null) {
196                 realClassName = value;
197             }
198         }
199         if (digester.log.isDebugEnabled()) {
200             digester.log.debug("[ObjectCreateRule]{" + digester.match +
201                     "}New " + realClassName);
202         }
203 
204         // Instantiate the new object and push it on the context stack
205         Class   clazz = digester.getClassLoader().loadClass(realClassName);
206         Object   instance = clazz.newInstance();
207         digester.push(instance);
208 
209     }
210 
211 
212     /**
213      * Process the end of this element.
214      */
215     public void end() throws Exception   {
216 
217         Object   top = digester.pop();
218         if (digester.log.isDebugEnabled()) {
219             digester.log.debug("[ObjectCreateRule]{" + digester.match +
220                     "} Pop " + top.getClass().getName());
221         }
222 
223     }
224 
225 
226     /**
227      * Render a printable version of this Rule.
228      */
229     public String   toString() {
230 
231         StringBuffer   sb = new StringBuffer  ("ObjectCreateRule[");
232         sb.append("className=");
233         sb.append(className);
234         sb.append(", attributeName=");
235         sb.append(attributeName);
236         sb.append("]");
237         return (sb.toString());
238 
239     }
240 
241 
242 }
243
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