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1   /*
2    * $Id: AbstractChildElementIterator.java 20321 2010-11-24 15:21:24Z dfeist $
3    * --------------------------------------------------------------------------------------
4    * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
5    *
6    * The software in this package is published under the terms of the CPAL v1.0
7    * license, a copy of which has been included with this distribution in the
8    * LICENSE.txt file.
9    */
10  
11  package org.mule.config.spring.parsers.processors;
12  
13  import org.mule.config.spring.parsers.PostProcessor;
14  import org.mule.config.spring.parsers.assembly.BeanAssembler;
15  import org.mule.config.spring.parsers.assembly.BeanAssemblerFactory;
16  import org.mule.config.spring.parsers.assembly.configuration.PropertyConfiguration;
17  import org.mule.config.spring.util.SpringXMLUtils;
18  
19  import org.springframework.beans.factory.xml.BeanDefinitionParserDelegate;
20  import org.springframework.beans.factory.xml.ParserContext;
21  import org.w3c.dom.Element;
22  import org.w3c.dom.Node;
23  import org.w3c.dom.NodeList;
24  
25  /**
26   * This iterates over child elements, parsing them and calling
27   * {@link #insertBean(org.mule.config.spring.parsers.assembly.BeanAssembler, org.springframework.beans.factory.config.BeanDefinition, org.w3c.dom.Element, org.w3c.dom.Element)}.
28   *
29   * <p>There are two ways we can parse a tree of elements - have an external loop or let each parser iterate
30   * over its own children.  Mule uses the first strategy, but some (most? all?) third party BDPs use the
31   * second.  This processor lets us use third party beans inside the Mule framework.
32   *
33   * <p>So this is a very specialised parser that should only be used when trying to inter-operate with beans from
34   * third party packages which themselves control how their children are parsed.
35   *
36   * <p>Since for Mule beans the iteration over child elements (at least currently) is done via
37   * {@link org.mule.config.spring.MuleHierarchicalBeanDefinitionParserDelegate} the calling parser needs to set
38   * the flag {@link org.mule.config.spring.MuleHierarchicalBeanDefinitionParserDelegate#MULE_NO_RECURSE} - this
39   * stops the Mule recursion from working.
40   *
41   * <p>NOTE - IMHO (ac) the Mule approach was probably a mistake; this processor could be used as a way to
42   * slowly migrate the Mule code to the more common approach.
43   */
44  public abstract class AbstractChildElementIterator implements PostProcessor
45  {
46  
47      private BeanAssemblerFactory beanAssemblerFactory;
48      private PropertyConfiguration configuration;
49  
50      public AbstractChildElementIterator(BeanAssemblerFactory beanAssemblerFactory, PropertyConfiguration configuration)
51      {
52          this.beanAssemblerFactory = beanAssemblerFactory;
53          this.configuration = configuration;
54      }
55  
56      public void postProcess(ParserContext context, BeanAssembler assembler, Element element)
57      {
58          NodeList children = element.getChildNodes();
59          for (int i = 0; i < children.getLength(); ++i)
60          {
61              Node child = children.item(i);
62              if (child.getNodeType() == Node.ELEMENT_NODE)
63              {
64                  processChildElement(context, assembler, element, (Element) child);
65              }
66          }
67      }
68  
69      protected void processChildElement(ParserContext context, BeanAssembler assembler, Element parent, Element child)
70      {
71          Object childBean = null;
72          if (SpringXMLUtils.isBeansNamespace(child)
73              || SpringXMLUtils.isLocalName(child, BeanDefinitionParserDelegate.REF_ELEMENT))
74          {
75              childBean = context.getDelegate().parsePropertySubElement(child, null);
76          }
77          else
78          {
79              childBean = context.getDelegate().parseCustomElement(child,
80                  assembler.getBean().getBeanDefinition());
81          }
82          BeanAssembler targetAssembler = beanAssemblerFactory.newBeanAssembler(null, null, configuration,
83              assembler.getBean().getRawBeanDefinition());
84          insertBean(targetAssembler, childBean, parent, child);
85      }
86  
87      protected abstract void insertBean(BeanAssembler targetAssembler, Object childBean, Element parent, Element child);
88  
89  }