TrAXFilter


1   /*
2    * Copyright 1999-2004 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  /*
17   * $Id: TrAXFilter.java,v 1.15 2004/02/23 17:09:48 jycli Exp $
18   */
19  package org.apache.xalan.transformer;
20  
21  import java.io.IOException  ;
22  
23  import javax.xml.transform.ErrorListener  ;
24  import javax.xml.transform.Templates  ;
25  import javax.xml.transform.TransformerConfigurationException  ;
26  
27  import org.apache.xalan.res.XSLMessages;
28  import org.apache.xalan.res.XSLTErrorResources;
29  
30  import org.xml.sax.ContentHandler  ;
31  import org.xml.sax.DTDHandler  ;
32  import org.xml.sax.EntityResolver  ;
33  import org.xml.sax.InputSource  ;
34  import org.xml.sax.XMLReader  ;
35  import org.xml.sax.helpers.XMLFilterImpl  ;
36  import org.xml.sax.helpers.XMLReaderFactory  ;
37  
38  
39  public class TrAXFilter extends XMLFilterImpl  
40  {
41    private Templates   m_templates;
42    private TransformerImpl m_transformer;
43      
44    /**
45     * Construct an empty XML filter, with no parent.
46     *
47     * <p>This filter will have no parent: you must assign a parent
48     * before you start a parse or do any configuration with
49     * setFeature or setProperty.</p>
50     *
51     * @see org.xml.sax.XMLReader#setFeature
52     * @see org.xml.sax.XMLReader#setProperty
53     */
54    public TrAXFilter (Templates   templates)
55      throws TransformerConfigurationException  
56    {
57      m_templates = templates;
58      m_transformer = (TransformerImpl)templates.newTransformer();
59    }
60    
61    /**
62     * Return the Transformer object used for this XML filter.
63     */
64    public TransformerImpl getTransformer()
65    {
66      return m_transformer;
67    }
68    
69    /** Set the parent reader.
70     *
71     * <p>This is the {@link org.xml.sax.XMLReader XMLReader} from which 
72     * this filter will obtain its events and to which it will pass its 
73     * configuration requests.  The parent may itself be another filter.</p>
74     *
75     * <p>If there is no parent reader set, any attempt to parse
76     * or to set or get a feature or property will fail.</p>
77     *
78     * @param parent The parent XML reader.
79     * @throws java.lang.NullPointerException If the parent is null.
80     */
81    public void setParent (XMLReader   parent)
82    { 
83      super.setParent(parent);
84      
85      if(null != parent.getContentHandler())
86        this.setContentHandler(parent.getContentHandler());
87  
88      // Not really sure if we should do this here, but 
89      // it seems safer in case someone calls parse() on 
90      // the parent.
91      setupParse ();
92    }
93    
94    /**
95     * Parse a document.
96     *
97     * @param input The input source for the document entity.
98     * @throws org.xml.sax.SAXException Any SAX exception, possibly
99     *            wrapping another exception.
100    * @throws java.io.IOException An IO exception from the parser,
101    *            possibly from a byte stream or character stream
102    *            supplied by the application.
103    * @see org.xml.sax.XMLReader#parse(org.xml.sax.InputSource)
104    */
105   public void parse (InputSource   input)
106     throws org.xml.sax.SAXException  , IOException  
107   {
108     if(null == getParent())
109     {
110       XMLReader   reader=null;
111 
112       // Use JAXP1.1 ( if possible )
113       try {
114           javax.xml.parsers.SAXParserFactory   factory=
115               javax.xml.parsers.SAXParserFactory.newInstance();
116           factory.setNamespaceAware( true );
117           javax.xml.parsers.SAXParser   jaxpParser=
118               factory.newSAXParser();
119           reader=jaxpParser.getXMLReader();
120           
121       } catch( javax.xml.parsers.ParserConfigurationException   ex ) {
122           throw new org.xml.sax.SAXException  ( ex );
123       } catch( javax.xml.parsers.FactoryConfigurationError   ex1 ) {
124           throw new org.xml.sax.SAXException  ( ex1.toString() );
125       } catch( NoSuchMethodError   ex2 ) {
126       }
127       catch (AbstractMethodError   ame){}
128 
129       XMLReader   parent;
130       if( reader==null )
131           parent= XMLReaderFactory.createXMLReader();
132       else
133           parent=reader;
134       try
135       {
136         parent.setFeature("http://xml.org/sax/features/namespace-prefixes",
137                           true);
138       }
139       catch (org.xml.sax.SAXException   se){}
140       // setParent calls setupParse...
141       setParent(parent);
142     }
143     else
144     {
145       // Make sure everything is set up.
146       setupParse ();
147     }
148     if(null == m_transformer.getContentHandler())
149     {
150       throw new org.xml.sax.SAXException  (XSLMessages.createMessage(XSLTErrorResources.ER_CANNOT_CALL_PARSE, null)); //"parse can not be called if the ContentHandler has not been set!");
151     }
152 
153     getParent().parse(input);
154     Exception   e = m_transformer.getExceptionThrown();
155     if(null != e)
156     {
157       if(e instanceof org.xml.sax.SAXException  )
158         throw (org.xml.sax.SAXException  )e;
159       else
160         throw new org.xml.sax.SAXException  (e);
161     }
162   }
163   
164   /**
165    * Parse a document.
166    *
167    * @param systemId The system identifier as a fully-qualified URI.
168    * @throws org.xml.sax.SAXException Any SAX exception, possibly
169    *            wrapping another exception.
170    * @throws java.io.IOException An IO exception from the parser,
171    *            possibly from a byte stream or character stream
172    *            supplied by the application.
173    * @see org.xml.sax.XMLReader#parse(java.lang.String)
174    */
175   public void parse (String   systemId)
176     throws org.xml.sax.SAXException  , IOException  
177   {
178     parse(new InputSource  (systemId));
179   }
180 
181 
182   /**
183    * Set up before a parse.
184    *
185    * <p>Before every parse, check whether the parent is
186    * non-null, and re-register the filter for all of the 
187    * events.</p>
188    */
189   private void setupParse ()
190   {
191     XMLReader   p = getParent();
192     if (p == null) {
193       throw new NullPointerException  (XSLMessages.createMessage(XSLTErrorResources.ER_NO_PARENT_FOR_FILTER, null)); //"No parent for filter");
194     }
195     
196     ContentHandler   ch = m_transformer.getInputContentHandler();
197 //    if(ch instanceof SourceTreeHandler)
198 //      ((SourceTreeHandler)ch).setUseMultiThreading(true);
199     p.setContentHandler(ch);
200     p.setEntityResolver(this);
201     p.setDTDHandler(this);
202     p.setErrorHandler(this);
203   }
204 
205   /**
206    * Set the content event handler.
207    *
208    * @param resolver The new content handler.
209    * @throws java.lang.NullPointerException If the handler
210    *            is null.
211    * @see org.xml.sax.XMLReader#setContentHandler
212    */
213   public void setContentHandler (ContentHandler   handler)
214   {
215     m_transformer.setContentHandler(handler);
216     // super.setContentHandler(m_transformer.getResultTreeHandler());
217   }
218   
219   public void setErrorListener (ErrorListener   handler)
220   {
221     m_transformer.setErrorListener(handler);
222   }
223 
224 }
225
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