EjenFilterNode


1   //
2   // Ejen (code generation system)
3   // Copyright (C) 2001, 2002 Fran�ois Wolff (ejen@noos.fr).
4   //
5   // This file is part of Ejen.
6   //
7   // Ejen is free software; you can redistribute it and/or modify
8   // it under the terms of the GNU General Public License as published by
9   // the Free Software Foundation; either version 2 of the License, or
10  // (at your option) any later version.
11  //
12  // Ejen is distributed in the hope that it will be useful,
13  // but WITHOUT ANY WARRANTY; without even the implied warranty of
14  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  // GNU General Public License for more details.
16  //
17  // You should have received a copy of the GNU General Public License
18  // along with Ejen; if not, write to the Free Software
19  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  //
21  package org.ejen;
22  
23  import java.util.Properties  ;
24  import javax.xml.transform.dom.DOMSource  ;
25  import javax.xml.transform.dom.DOMResult  ;
26  import org.w3c.dom.Document  ;
27  import org.w3c.dom.Node  ;
28  import org.w3c.dom.NodeList  ;
29  import org.apache.xpath.XPathAPI;
30  import org.apache.xalan.transformer.TransformerImpl;
31  
32  /**
33   * Filter node class.
34   * <p>
35   * A filter node tranforms the current in memory DOM tree.
36   * <p>
37   * <table class="usage">
38   * <tr><th class="usage">Usage (ant build file)</th></tr>
39   * <tr><td class="usage"><pre><code>
40   *  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
41   *
42   *  &lt;project name="generate" default="build"&gt;
43   *
44   *    &lt;taskdef name="ejen" classname="org.ejen.EjenTask"/&gt;
45   *
46   *    &lt;target name="build"&gt;
47   *      &lt;{@link org.ejen.EjenTask ejen} ...&gt;
48   *        ...
49   *        <b>&lt;filter {@link org.ejen.EjenStylesheetNode#setFile(String) file}="filter.xml"
50   *               [{@link #setForeach(String) foreach}="/ejen/entity-bean"]&gt;</b>
51   *          ...
52   *          [&lt;{@link org.ejen.EjenIncludeNode include} .../&gt;]
53   *          [&lt;{@link org.ejen.EjenImportNode import} .../&gt;]
54   *          [&lt;{@link org.ejen.EjenParamNode param} .../&gt;]
55   *          ...
56   *        <b>&lt;/filter&gt;</b>
57   *        ...
58   *      &lt;/ejen&gt;
59   *    &lt;/target&gt;
60   *
61   *  &lt;/project&gt;
62   * </code></pre></td></tr></table>
63   * <p>
64   * <b>Parent nodes</b>:
65   * <ul>
66   *   <li>{@link org.ejen.EjenTask ejen}
67   * </ul>
68   * @author F. Wolff
69   * @version 1.0
70   */
71  public class EjenFilterNode extends EjenStylesheetNode {
72      protected String   _foreach = null;
73  
74      /**
75       * Returns the name of this EjenFilterNode (always "filter").
76       * @return the name of this EjenFilterNode.
77       */
78      public String   nodeName() {
79          return "filter";
80      }
81  
82      /**
83       * Returns all non null attributes of this EjenFilterNode.
84       * @return non null attributes of this EjenFilterNode.
85       */
86      public Properties   getAttributes() {
87          Properties   attrs = super.getAttributes();
88  
89          if (_foreach != null) {
90              attrs.setProperty("foreach", _foreach);
91          }
92          return attrs;
93      }
94  
95      /**
96       * <b>[optional/AVT]</b> - sets the foreach attribute. This attribute
97       * allows iterative applications of this filter stylesheet to a sub-nodes
98       * set of the current in memory DOM tree.
99       * <p>
100      * Suppose you have the following DOM tree in memory:
101      * <table class="usage">
102      * <tr><td class="usage"><pre><code>
103      *  &lt;?xml version="1.0" encoding="iso-8859-1"?&gt;
104      *  &lt;ejen&gt;
105      *    &lt;name&gt;Name1&lt;/name&gt;
106      *    &lt;name&gt;Name2&lt;/name&gt;
107      *    &lt;name&gt;Name3&lt;/name&gt;
108      *    ...
109      *  &lt;/ejen&gt;
110      * </code></pre></td></tr></table>
111      * You want to transform it into this DOM tree:
112      * <table class="usage">
113      * <tr><td class="usage"><pre><code>
114      *  &lt;?xml version="1.0" encoding="iso-8859-1"?&gt;
115      *  &lt;ejen&gt;
116      *    &lt;name&gt;Dear Name1&lt;/name&gt;
117      *    &lt;name&gt;Dear Name2&lt;/name&gt;
118      *    &lt;name&gt;Dear Name3&lt;/name&gt;
119      *    ...
120      *  &lt;/ejen&gt;
121      * </code></pre></td></tr></table>
122      * You can use this filter stylesheet (with the foreach attribute set to "/ejen/name"):
123      * <table class="usage">
124      * <tr><td class="usage"><pre><code>
125      *  &lt;?xml version="1.0" encoding="iso-8859-1"?&gt;
126      *  &lt;xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
127      *                  version="1.0"&gt;
128      *    &lt;xsl:output method="xml" encoding="iso-8859-1"/&gt;
129      *    <b>&lt;xsl:template match="name"&gt;
130      *      &lt;name&gt;Dear &lt;xsl:value-of select="."/&gt;&lt;/name&gt;
131      *    &lt;/xsl:template&gt;</b>
132      *  &lt;/xsl:stylesheet&gt;
133      * </code></pre></td></tr></table>
134      * <p>
135      * If this attribute is used, a parameter whose name is "root" and value is the root
136      * node of the current DOM tree is always and automaticaly passed to the filter
137      * stylesheet (you may have the line "<code>&lt;xsl:param name"root"/&gt;</code>" in
138      * the stylesheet).
139      * <p>
140      * @param foreach foreach String (default is null, meaning "apply this filter
141      *        stylesheet to the entire current DOM tree").
142      */
143     public void setForeach(String   foreach) {
144         _foreach = foreach;
145     }
146     
147     /**
148      * Executes this EjenFilterNode.
149      * @throws org.ejen.EjenException if something goes wrong...
150      */
151     public void process() {
152         super.process();
153         TransformerImpl ti = null;
154         DOMSource   src = null;
155 
156         try {
157             ti = (TransformerImpl) (getFromContext(CTX_TRANSFORMER_IMPL));
158             src = (DOMSource  ) (getFromGlobalContext(CTX_DOM_SOURCE));
159         } catch (Exception   e) {
160             throw new EjenException(this, null, e);
161         }
162         if (ti == null) {
163             throw new EjenException(this,
164                     "no '" + CTX_TRANSFORMER_IMPL + "' in context");
165         }
166         if (src == null) {
167             throw new EjenException(this,
168                     "no '" + CTX_DOM_SOURCE + "' in global context");
169         }
170         if (_foreach != null) {
171             NodeList   nl = null;
172 
173             try {
174                 ti.setParameter("root", src.getNode());
175                 nl = XPathAPI.selectNodeList(src.getNode(),
176                         evaluateAVT(ti, _foreach));
177             } catch (Exception   e) {
178                 throw new EjenException(this,
179                         "invalid 'foreach' attribute: " + _foreach, e);
180             }
181             try {
182                 Document   doc = (Document  ) (src.getNode());
183 
184                 for (int i = 0; i < nl.getLength(); i++) {
185                     Node   parent = nl.item(i).getParentNode();
186 
187                     if (parent == null) {
188                         throw new EjenException(this,
189                                 "Invalid 'foreach' attribute:" + _foreach
190                                 + " (node " + i + " has no parent)");
191                     }
192                     DOMResult   res = new DOMResult  ();
193 
194                     ti.transform(new DOMSource  (nl.item(i)), res);
195                     Node   root = doc.importNode(((Document  ) (res.getNode())).getDocumentElement(),
196                             true);
197 
198                     parent.replaceChild(root, nl.item(i));
199                 }
200             } catch (EjenException e) {
201                 throw e;
202             } catch (Exception   e) {
203                 throw new EjenException(this, null, e);
204             }
205         } else {
206             DOMResult   res = new DOMResult  ();
207 
208             try {
209                 ti.transform(src, res);
210                 putInGlobalContext(CTX_DOM_SOURCE, new DOMSource  (res.getNode()));
211             } catch (Exception   e) {
212                 throw new EjenException(this, null, e);
213             }
214         }
215     }
216 }
217
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags