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1   /*
2    * $Id: MuleBeanDefinitionReader.java 7976 2007-08-21 14:26:13Z dirk.olmes $
3    * --------------------------------------------------------------------------------------
4    * Copyright (c) MuleSource, Inc.  All rights reserved.  http://www.mulesource.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.extras.spring.config;
12  
13  import org.mule.config.MuleDtdResolver;
14  import org.mule.umo.transformer.UMOTransformer;
15  
16  import java.io.IOException;
17  
18  import javax.xml.transform.Source;
19  import javax.xml.transform.Transformer;
20  import javax.xml.transform.TransformerConfigurationException;
21  import javax.xml.transform.TransformerException;
22  import javax.xml.transform.TransformerFactory;
23  import javax.xml.transform.dom.DOMResult;
24  import javax.xml.transform.dom.DOMSource;
25  import javax.xml.transform.stream.StreamSource;
26  
27  import org.dom4j.io.DOMReader;
28  import org.springframework.beans.BeansException;
29  import org.springframework.beans.FatalBeanException;
30  import org.springframework.beans.factory.support.BeanDefinitionRegistry;
31  import org.springframework.beans.factory.support.DefaultListableBeanFactory;
32  import org.springframework.beans.factory.xml.BeansDtdResolver;
33  import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
34  import org.springframework.core.io.ClassPathResource;
35  import org.springframework.core.io.Resource;
36  import org.w3c.dom.Document;
37  import org.xml.sax.EntityResolver;
38  
39  /**
40   * <code>MuleBeanDefinitionReader</code> Is a custom Spring Bean reader that will
41   * apply a transformation to Mule Xml configuration files before loading bean
42   * definitions allowing Mule Xml config to be parsed as Spring configuration.
43   */
44  public class MuleBeanDefinitionReader extends XmlBeanDefinitionReader
45  {
46      private int contextCount = 0;
47      private int configCount = 0;
48      private MuleDtdResolver dtdResolver = null;
49  
50      public MuleBeanDefinitionReader(BeanDefinitionRegistry beanDefinitionRegistry, int configCount)
51      {
52          super(beanDefinitionRegistry);
53  
54          setDocumentReaderClass(MuleBeanDefinitionDocumentReader.class);
55          setResourceLoader(new MuleResourceLoader());
56          // TODO Make this configurable as a property somehow.
57          setValidationMode(VALIDATION_DTD);
58          setEntityResolver(createEntityResolver());
59          this.configCount = configCount;
60          
61          // TransformerEditor is used to convert Transformer names into transformer Objects.
62          ((DefaultListableBeanFactory)beanDefinitionRegistry).registerCustomEditor(UMOTransformer.class,
63              new TransformerEditor());
64      }
65  
66      public int registerBeanDefinitions(Document document, Resource resource) throws BeansException
67      {
68          try
69          {
70              Document newDocument = transformDocument(document);
71              return super.registerBeanDefinitions(newDocument, resource);
72          }
73          catch (Exception e)
74          {
75              throw new FatalBeanException("Failed to read config resource: " + resource, e);
76          }
77          finally
78          {
79              incConfigCount();
80          }
81      }
82  
83      public static Transformer createTransformer(Source source) throws TransformerConfigurationException
84      {
85          TransformerFactory factory = TransformerFactory.newInstance();
86          Transformer transformer = factory.newTransformer(source);
87          return transformer;
88      }
89  
90      protected Document transformDocument(Document document) throws IOException, TransformerException
91      {
92          if (getXslResource() != null)
93          {
94              Transformer transformer = createTransformer(createXslSource());
95              DOMResult result = new DOMResult();
96              transformer.setParameter("firstContext", Boolean.valueOf(isFirstContext()));
97              transformer.transform(new DOMSource(document), result);
98              if (logger.isDebugEnabled())
99              {
100                 try
101                 {
102                     String xml = new DOMReader().read((Document)result.getNode()).asXML();
103                     if (logger.isDebugEnabled())
104                     {
105                         logger.debug("Transformed document is:\n" + xml);
106                     }
107                 }
108                 catch (Exception e)
109                 {
110                     e.printStackTrace();
111                 }
112             }
113             return (Document)result.getNode();
114         }
115         else
116         {
117             return document;
118         }
119 
120     }
121 
122     protected Source createXslSource() throws IOException
123     {
124         return new StreamSource(getXslResource().getInputStream(), getXslResource().getURL().toString());
125     }
126 
127     protected ClassPathResource getXslResource()
128     {
129         String xsl = dtdResolver.getXslForDtd();
130         if (xsl != null)
131         {
132             return new ClassPathResource(xsl);
133         }
134         else
135         {
136             return null;
137         }
138     }
139 
140     protected EntityResolver createEntityResolver()
141     {
142         if (dtdResolver == null)
143         {
144             MuleDtdResolver muleSpringResolver = new MuleDtdResolver("mule-spring-configuration.dtd",
145                 "mule-to-spring.xsl", new BeansDtdResolver());
146             dtdResolver = new MuleDtdResolver("mule-configuration.dtd", "mule-to-spring.xsl",
147                 muleSpringResolver);
148         }
149         return dtdResolver;
150     }
151 
152     public boolean isFirstContext()
153     {
154         return contextCount == 0;
155     }
156 
157     private void incConfigCount()
158     {
159         contextCount++;
160         if (contextCount >= configCount)
161         {
162             contextCount = 0;
163         }
164     }
165 }