XMLHelper


1   /*
2    * $Id: XMLHelper.java,v 1.4 2002/04/02 21:50:35 awason Exp $
3    *
4    * ===========================================================================
5    *
6    * The JGenerator Software License, Version 1.0
7    *
8    * Copyright (c) 2000 Dmitry Skavish (skavish@usa.net). All rights reserved.
9    *
10   * Redistribution and use in source and binary forms, with or without
11   * modification, are permitted provided that the following conditions are met:
12   *
13   * 1. Redistributions of source code must retain the above copyright
14   *    notice, this list of conditions and the following disclaimer.
15   *
16   * 2. Redistributions in binary form must reproduce the above copyright
17   *    notice, this list of conditions and the following disclaimer in
18   *    the documentation and/or other materials provided with the
19   *    distribution.
20   *
21   * 3. The end-user documentation included with the redistribution, if
22   *    any, must include the following acknowlegement:
23   *    "This product includes software developed by Dmitry Skavish
24   *     (skavish@usa.net, http://www.flashgap.com/)."
25   *    Alternately, this acknowlegement may appear in the software itself,
26   *    if and wherever such third-party acknowlegements normally appear.
27   *
28   * 4. The name "The JGenerator" must not be used to endorse or promote
29   *    products derived from this software without prior written permission.
30   *    For written permission, please contact skavish@usa.net.
31   *
32   * 5. Products derived from this software may not be called "The JGenerator"
33   *    nor may "The JGenerator" appear in their names without prior written
34   *    permission of Dmitry Skavish.
35   *
36   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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40   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
43   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
44   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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46   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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49   */
50  
51  package org.openlaszlo.iv.flash.xml;
52  
53  import java.io.*;
54  import java.net.*;
55  import java.util.*;
56  
57  import java.io.FileInputStream  ;
58  import java.io.FileNotFoundException  ;
59  import java.util.Properties  ;
60  
61  import org.w3c.dom.*;
62  import org.w3c.dom.traversal.*;
63  import org.xml.sax.SAXException  ;
64  import org.xml.sax.InputSource  ;
65  
66  import javax.xml.parsers.*;
67  import javax.xml.transform.*;
68  
69  import org.openlaszlo.iv.flash.api.*;
70  import org.openlaszlo.iv.flash.url.*;
71  import org.openlaszlo.iv.flash.util.*;
72  
73  import org.openlaszlo.iv.flash.cache.*;
74  
75  import org.xml.sax.EntityResolver  ;
76  import org.xml.sax.InputSource  ;
77  
78  /**
79   * XMl Helper class.
80   * <P>
81   * Provides various methods for XML stuff
82   *
83   * @author Dmitry Skavish
84   */
85  public class XMLHelper {
86  
87      private static XMLFactory factory = XMLFactory.getFactory();
88  
89      /**
90       * Returns XMLFactory
91       *
92       * @return xml factory
93       */
94      public static XMLFactory getXMLFactory() {
95          return factory;
96      }
97  
98      /**
99       * Returns DocumentBuilder or null
100      *
101      * @return DocumentBuilder or null
102      */
103     public static DocumentBuilder getDocumentBuilder() {
104         try {
105             return factory.getDocumentBuilder();
106         } catch( ParserConfigurationException e ) {
107             Log.logRB(e);
108             return null;
109         }
110     }
111 
112     /**
113      * Creates new empty xml document
114      *
115      * @return new empty xml document
116      */
117     public static Document newDocument() {
118         return getDocumentBuilder().newDocument();
119     }
120 
121     /**
122      * Parses input stream of some xml data into xml document.
123      *
124      * @param is     xml input stream
125      * @return xml document
126      * @exception IOException
127      * @exception SAXException
128      */
129     public static Document parse( InputStream   is ) throws IOException, SAXException   {
130         return parse( new InputSource  (is) );
131     }
132 
133     /**
134      * Parses input source of some xml data into xml document.
135      *
136      * @param isrc   xml input source
137      * @return xml document
138      * @exception IOException
139      * @exception SAXException
140      */
141     public static Document parse( InputSource   isrc ) throws IOException, SAXException   {
142         return getDocumentBuilder().parse( isrc );
143     }
144 
145     /**
146      * Parses xml document specified by url.
147      * <P>
148      * First tries to retrieve xml document from cache.
149      * If it is not cached then reads it, parses it and caches (if needed).
150      *
151      * @param url    url to xml document
152      * @return xml document
153      * @exception IOException
154      * @exception SAXException
155      */
156     public static Document getDocument( IVUrl url ) throws IOException, SAXException   {
157         Document doc = XMLCache.getXMLDocument( url );
158         if( doc != null ) return doc;
159         doc = parse( url.getInputStream() );
160         XMLCache.addXMLDocument( url, doc );
161         return doc;
162     }
163 
164     /**
165      * Parses xml document specified by url and resolves it to one node.
166      * <P>
167      * First tries to retrieve xml document from cache.
168      * If it is not cached then reads it, parses it and caches (if needed).
169      * Then if there is no any xpath expression in url returns Document itself as a xml node.
170      * If there is some Xpath then evaluates this XPath to one xml node and returns it.
171      * <P>
172      * The url's format: <url itself>#<xpath expression which returns single node><BR>
173      * Example: <CODE>http://myserver.com/mydata.xml#/doc/item/firstNode</CODE>
174      *
175      * @param url    url to xml document
176      * @return xml node
177      * @exception IOException
178      * @exception SAXException
179      */
180     public static Node getNode( IVUrl url ) throws IOException, SAXException   {
181         Document doc = getDocument( url );
182         String   ref = url.getRef();
183         if( ref == null ) return doc;
184         Node node;
185         try {
186             node = getXMLFactory().getXPathProcessor().selectSingleNode(ref, doc);
187         } catch( TransformerException e ) {
188             throw new SAXException  (e);
189         }
190         return node;
191     }
192 
193 }
194
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