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1   /*
2    * Copyright 2002,2004 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.jelly.tags.core;
17  
18  import java.lang.reflect.InvocationTargetException;
19  import java.util.Map;
20  
21  import org.apache.commons.beanutils.BeanUtils;
22  
23  import org.apache.commons.jelly.JellyException;
24  import org.apache.commons.jelly.JellyTagException;
25  import org.apache.commons.jelly.MissingAttributeException;
26  import org.apache.commons.jelly.MapTagSupport;
27  import org.apache.commons.jelly.XMLOutput;
28  import org.apache.commons.jelly.impl.BeanSource;
29  
30  /***
31   * A tag which sets the bean properties on the given bean.
32   * So if you used it as follows, for example using the <j:new> tag.
33   * <pre>
34   * &lt;j:new className="com.acme.Person" var="person"/&gt;
35   * &lt;j:setProperties object="${person}" name="James" location="${loc}"/&gt;
36   * </pre>
37   * Then it would set the name and location properties on the bean denoted by
38   * the expression ${person}.
39   * <p>
40   * This tag can also be nested inside a bean tag such as the &lt;useBean&gt; tag
41   * or a JellySwing tag to set one or more properties, maybe inside some conditional
42   * logic.
43   *
44   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
45   * @version $Revision: 155420 $
46   */
47  public class SetPropertiesTag extends MapTagSupport  {
48  
49      public SetPropertiesTag(){
50      }
51  
52      // Tag interface
53      //-------------------------------------------------------------------------
54      public void doTag(XMLOutput output) throws MissingAttributeException, JellyTagException {
55          Map attributes = getAttributes();
56          Object bean = attributes.remove( "object" );
57          if ( bean == null ) {
58              // lets try find a parent bean
59              BeanSource tag = (BeanSource) findAncestorWithClass(BeanSource.class);
60              if (tag != null) {
61                  try {
62                      bean = tag.getBean();
63                  } catch (JellyException e) {
64                      throw new JellyTagException(e);
65                  }
66              }
67              if (bean == null) {
68                  throw new MissingAttributeException("bean");
69              }
70          }
71          setBeanProperties(bean, attributes);
72      }
73  
74      // Implementation methods
75      //-------------------------------------------------------------------------
76  
77      /***
78       * Sets the properties on the bean. Derived tags could implement some custom
79       * type conversion etc.
80       */
81      protected void setBeanProperties(Object bean, Map attributes) throws JellyTagException {
82          try {
83              BeanUtils.populate(bean, attributes);
84          } catch (IllegalAccessException e) {
85              throw new JellyTagException("could not set the properties on a bean",e);
86          } catch (InvocationTargetException e) {
87              throw new JellyTagException("could not set the properties on a bean",e);
88          }
89      }
90  }