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Java > Open Source Codes > org > apache > commons > betwixt > digester > AddDefaultsRule


1 /*
2  * Copyright 2001-2004 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 package org.apache.commons.betwixt.digester;
17
18 import java.beans.BeanInfo JavaDoc;
19 import java.beans.Introspector JavaDoc;
20 import java.beans.PropertyDescriptor JavaDoc;
21 import java.util.Set JavaDoc;
22
23 import org.apache.commons.betwixt.AttributeDescriptor;
24 import org.apache.commons.betwixt.BeanProperty;
25 import org.apache.commons.betwixt.Descriptor;
26 import org.apache.commons.betwixt.ElementDescriptor;
27 import org.apache.commons.betwixt.NodeDescriptor;
28 import org.apache.commons.betwixt.XMLBeanInfo;
29 import org.apache.commons.logging.Log;
30 import org.apache.commons.logging.LogFactory;
31 import org.xml.sax.Attributes JavaDoc;
32 import org.xml.sax.SAXException JavaDoc;
33
34 /** <p><code>AddDefaultsRule</code> appends all the default properties
35   * to the current element.</p>
36   *
37   * @author <a HREF="mailto:jstrachan@apache.org">James Strachan</a>
38   */
39 public class AddDefaultsRule extends RuleSupport {
40
41     /** Logger */
42     private static final Log log = LogFactory.getLog( AddDefaultsRule.class );
43     
44     /** Base constructor */
45     public AddDefaultsRule() {
46     }
47     
48     // Rule interface
49 //-------------------------------------------------------------------------
50
51     /**
52      * Process the beginning of this element.
53      *
54      * @param attributes The attribute list of this element
55      * @throws Exception generally this will indicate an unrecoverable error
56      */
57     public void begin(String JavaDoc name, String JavaDoc namespace, Attributes JavaDoc attributes) throws Exception JavaDoc {
58         boolean addProperties = true;
59         String JavaDoc addPropertiesAttributeValue = attributes.getValue("add-properties");
60         if (addPropertiesAttributeValue != null)
61         {
62             addProperties = Boolean.valueOf(addPropertiesAttributeValue).booleanValue();
63         }
64         
65         boolean addAdders = true;
66         String JavaDoc addAddersAttributeValue = attributes.getValue("add-adders");
67         if (addAddersAttributeValue != null)
68         {
69             addProperties = Boolean.valueOf(addAddersAttributeValue).booleanValue();
70         }
71         
72         if (addProperties) {
73             addDefaultProperties();
74         }
75         
76         if (addAdders) {
77             addAdders();
78         }
79     }
80
81     /**
82      * Adds default adder methods
83      */
84     private void addAdders() {
85         Class JavaDoc beanClass = getBeanClass();
86         // default any addProperty() methods
87 getXMLIntrospector().defaultAddMethods(
88                                             getRootElementDescriptor(),
89                                             beanClass );
90     }
91
92     /**
93      * Adds default property methods
94      *
95      */
96     private void addDefaultProperties() {
97         Class JavaDoc beanClass = getBeanClass();
98         Set JavaDoc processedProperties = getProcessedPropertyNameSet();
99         if ( beanClass != null ) {
100             try {
101                 boolean attributesForPrimitives = getXMLInfoDigester().isAttributesForPrimitives();
102                 BeanInfo JavaDoc beanInfo = Introspector.getBeanInfo( beanClass );
103                 PropertyDescriptor JavaDoc[] descriptors = beanInfo.getPropertyDescriptors();
104                 if ( descriptors != null ) {
105                     for ( int i = 0, size = descriptors.length; i < size; i++ ) {
106                         PropertyDescriptor JavaDoc descriptor = descriptors[i];
107                         // have we already created a property for this
108 String JavaDoc propertyName = descriptor.getName();
109                         if ( processedProperties.contains( propertyName ) ) {
110                             continue;
111                         }
112                         Descriptor JavaDoc nodeDescriptor =
113                             getXMLIntrospector().createXMLDescriptor(new BeanProperty(descriptor));
114                         if ( nodeDescriptor != null ) {
115                             addDescriptor( nodeDescriptor );
116                         }
117                     }
118                 }
119             } catch (Exception JavaDoc e) {
120                 log.info( "Caught introspection exception", e );
121             }
122         }
123     }
124
125
126     // Implementation methods
127 //-------------------------------------------------------------------------
128
129     /**
130     * Add a desciptor to the top object on the Digester stack.
131     *
132     * @param nodeDescriptor add this <code>NodeDescriptor</code>. Must not be null.
133     * @throws SAXException if the parent for the addDefaults element is not a <element>
134     * or if the top object on the stack is not a <code>XMLBeanInfo</code> or a
135     * <code>ElementDescriptor</code>
136     * @deprecated 0.5 replaced {@link #addDescriptor( Descriptor )}
137     */
138     protected void addDescriptor( NodeDescriptor nodeDescriptor ) throws SAXException JavaDoc {
139         addDescriptor( (Descriptor JavaDoc) nodeDescriptor );
140     }
141       
142     /**
143     * Add a desciptor to the top object on the Digester stack.
144     *
145     * @param nodeDescriptor add this <code>NodeDescriptor</code>. Must not be null.
146     * @throws SAXException if the parent for the addDefaults element is not a <element>
147     * or if the top object on the stack is not a <code>XMLBeanInfo</code> or a
148     * <code>ElementDescriptor</code>
149     * @since 0.5
150     */
151     protected void addDescriptor( Descriptor JavaDoc nodeDescriptor ) throws SAXException JavaDoc {
152         Object JavaDoc top = digester.peek();
153         if ( top instanceof XMLBeanInfo ) {
154             log.warn( "It is advisable to put an <addDefaults/> element inside an <element> tag" );
155             
156             XMLBeanInfo beanInfo = (XMLBeanInfo) top;
157             // if there is already a root element descriptor then use it
158 // otherwise use this descriptor
159 if ( nodeDescriptor instanceof ElementDescriptor ) {
160                 ElementDescriptor elementDescriptor = (ElementDescriptor) nodeDescriptor;
161                 ElementDescriptor root = beanInfo.getElementDescriptor() ;
162                 if ( root == null ) {
163                     beanInfo.setElementDescriptor( elementDescriptor );
164                 } else {
165                     root.addElementDescriptor( elementDescriptor );
166                 }
167             } else {
168                 throw new SAXException JavaDoc(
169                     "the <addDefaults> element should be within an <element> tag" );
170             }
171         } else if ( top instanceof ElementDescriptor ) {
172             ElementDescriptor parent = (ElementDescriptor) top;
173             if ( nodeDescriptor instanceof ElementDescriptor ) {
174                 parent.addElementDescriptor( (ElementDescriptor) nodeDescriptor );
175             } else {
176                 parent.addAttributeDescriptor( (AttributeDescriptor) nodeDescriptor );
177             }
178         } else {
179             throw new SAXException JavaDoc(
180                 "Invalid use of <addDefaults>. It should be nested inside <element> element" );
181         }
182     }
183
184     /**
185      * Gets an <code>ElementDescriptor</code> for the top on digester's stack.
186      *
187      * @return the top object or the element description if the top object
188      * is an <code>ElementDescriptor</code> or a <code>XMLBeanInfo</code> class (respectively)
189      * Otherwise null.
190      */
191     protected ElementDescriptor getRootElementDescriptor() {
192         Object JavaDoc top = digester.peek();
193         if ( top instanceof XMLBeanInfo ) {
194             XMLBeanInfo beanInfo = (XMLBeanInfo) top;
195             return beanInfo.getElementDescriptor();
196             
197         } else if ( top instanceof ElementDescriptor ) {
198             ElementDescriptor parent = (ElementDescriptor) top;
199             // XXX: could maybe walk up the parent hierarchy?
200 return parent;
201         }
202         return null;
203     }
204 }
205
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