EjenTemplateNode


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 org.ejen.util.XSLUtil;
24  import java.util.Properties  ;
25  import java.io.File  ;
26  import java.io.OutputStream  ;
27  import java.io.FileOutputStream  ;
28  import java.io.StringWriter  ;
29  import javax.xml.transform.stream.StreamResult  ;
30  import javax.xml.transform.dom.DOMSource  ;
31  import org.w3c.dom.NodeList  ;
32  import org.apache.xpath.XPathAPI;
33  import org.apache.xalan.transformer.TransformerImpl;
34  import org.apache.xalan.processor.StylesheetHandler;
35  
36  /**
37   * Template node class.
38   * <p>
39   * A template node uses the current in memory DOM tree to create resulting
40   * text files (XML, HTML, source code, ...).
41   * <p>
42   * <table class="usage">
43   * <tr><th class="usage">Usage (ant build file)</th></tr>
44   * <tr><td class="usage"><pre><code>
45   *  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
46   *
47   *  &lt;project name="generate" default="build"&gt;
48   *
49   *    &lt;taskdef name="ejen" classname="org.ejen.EjenTask"/&gt;
50   *
51   *    &lt;target name="build"&gt;
52   *      &lt;{@link org.ejen.EjenTask ejen} ...&gt;
53   *        ...
54   *        <b>&lt;template {@link org.ejen.EjenStylesheetNode#setFile(String) file}="filter.xml"
55   *                 [{@link #setForeach(String) foreach}="/ejen/entity-bean"]
56   *                 [{@link #setFilepattern(String) filepattern}="EJB_{&#064;table-name}Bean.java"]&gt;</b>
57   *          ...
58   *          [&lt;{@link org.ejen.EjenIncludeNode include} .../&gt;]
59   *          [&lt;{@link org.ejen.EjenImportNode import} .../&gt;]
60   *          [&lt;{@link org.ejen.EjenParamNode param} .../&gt;]
61   *          ...
62   *        <b>&lt;/template&gt;</b>
63   *        ...
64   *      &lt;/ejen&gt;
65   *    &lt;/target&gt;
66   *
67   *  &lt;/project&gt;
68   * </code></pre></td></tr></table>
69   * <p>
70   * <b>Parent nodes</b>:
71   * <ul>
72   *   <li>{@link org.ejen.EjenTask ejen}
73   * </ul>
74   * @author F. Wolff
75   * @version 1.0
76   */
77  public class EjenTemplateNode extends EjenStylesheetNode {
78      protected String   _foreach = null;
79      protected String   _filepattern = null;
80      protected String   _outdated = null;
81  
82      /**
83       * Returns the name of this EjenTemplateNode (always "template").
84       * @return the name of this EjenTemplateNode.
85       */
86      public String   nodeName() {
87          return "template";
88      }
89  
90      /**
91       * Returns all non null attributes of this EjenTemplateNode.
92       * @return non null attributes of this EjenTemplateNode.
93       */
94      public Properties   getAttributes() {
95          Properties   attrs = super.getAttributes();
96  
97          if (_foreach != null) {
98              attrs.setProperty("foreach", _foreach);
99          }
100         if (_filepattern != null) {
101             attrs.setProperty("filepattern", _filepattern);
102         }
103         if (_outdated != null) {
104             attrs.setProperty("outdated", _outdated);
105         }
106         return attrs;
107     }
108 
109     /**
110      * <b>[optional/AVT]</b> - sets the foreach attribute. This attribute
111      * allows iterative applications of this template stylesheet to a sub-nodes
112      * set of the current in memory DOM tree.
113      * <p>
114      * Suppose you have the following DOM tree in memory:
115      * <table class="usage">
116      * <tr><td class="usage"><pre><code>
117      *  &lt;?xml version="1.0" encoding="iso-8859-1"?&gt;
118      *  &lt;ejen&gt;
119      *    &lt;name&gt;Name1&lt;/name&gt;
120      *    &lt;name&gt;Name2&lt;/name&gt;
121      *    &lt;name&gt;Name3&lt;/name&gt;
122      *    ...
123      *  &lt;/ejen&gt;
124      * </code></pre></td></tr></table>
125      * You want to generate text files with the following structure:
126      * <table class="usage">
127      * <tr><td class="usage"><pre><code>
128      *  Dear &lt;Name...&gt;,
129      *    Obviously, you are reading a meaningless letter.
130      *  Best regards.
131      * </code></pre></td></tr></table>
132      * You can use this template stylesheet (with the foreach attribute set to "/ejen/name"):
133      * <table class="usage">
134      * <tr><td class="usage"><pre><code>
135      *  &lt;?xml version="1.0" encoding="iso-8859-1"?&gt;
136      *  &lt;xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
137      *                  version="1.0"&gt;
138      *    &lt;xsl:output method="text" encoding="iso-8859-1"/&gt;
139      *    <b>&lt;xsl:template match="name"&gt;&lt;!--
140      *   --&gt;Dear &lt;xsl:value-of select="."/&gt;,
141      *    Obviously, you are reading a meaningless letter.
142      *  Best regards.&lt;!--
143      *   --&gt;&lt;/xsl:template&gt;</b>
144      *  &lt;/xsl:stylesheet&gt;
145      * </code></pre></td></tr></table>
146      * Note that comments in this template are only for carriage return control
147      * purposes (we want neither a carriage return before "Dear", nor after "regards.").
148      * <p>
149      * If this attribute is used, a parameter whose name is "root" and value is the root
150      * node of the current DOM tree is always and automaticaly passed to the template
151      * stylesheet (you may have the line "<code>&lt;xsl:param name"root"/&gt;</code>" in
152      * the stylesheet).
153      * <p>
154      * See the {@link #setFilepattern(String) filepattern} for output file naming.
155      * <p>
156      * @param foreach foreach String (default is null, meaning "apply this template
157      *        stylesheet to the entire current DOM tree").
158      */
159     public void setForeach(String   foreach) {
160         _foreach = foreach;
161     }
162 
163     /**
164      * <b>[optional/AVT]</b> - sets the filepattern attribute. This attribute
165      * allows basic file output naming setting and is relative to the foreach
166      * attribute (if foreach attribute is not used, filepattern will be relative
167      * to the root node of the current in memory DOM tree).
168      * <p>
169      * Suppose what is supposed {@link #setForeach(String) here}. You want to
170      * generate text files whose names are: Name1.txt, Name2.txt,
171      * Name3.txt... Then, you can use this filepattern: "{.}.txt".
172      * <p>
173      * If this basic file output naming mechanism is not sufficient, you may still
174      * use the Xalan
175      * <a HREF="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/lib/Redirect.html">Redirect</a>
176      * extension.
177      * <p>
178      * @param filepattern filepattern String (default is null, meaning "let the
179      *        template do whatever it wants").
180      */
181     public void setFilepattern(String   filepattern) {
182         _filepattern = filepattern;
183     }
184 
185     /**
186      * <b>[optional/AVT]</b> - sets the outdate attribute.
187      * @param outdate if that attribute is "true" output file will generate only
188      *        if source file is newer then output file, otherwise output file generate always 
189      */
190     public void setOutdated(String   outdate) {
191         _outdated = outdate;
192     }
193     
194     /**
195      * Executes this EjenTemplateNode.
196      * @throws org.ejen.EjenException if something goes wrong...
197      */
198     public void process() {
199         super.process();
200         TransformerImpl ti = null;
201         DOMSource   src = null;
202 
203         try {
204             ti = (TransformerImpl) (getFromContext(CTX_TRANSFORMER_IMPL));
205             src = (DOMSource  ) (getFromGlobalContext(CTX_DOM_SOURCE));
206         } catch (Exception   e) {
207             throw new EjenException(this, null, e);
208         }
209         if (ti == null) {
210             throw new EjenException(this,
211                     "no '" + CTX_TRANSFORMER_IMPL + "' in context");
212         }
213         if (src == null) {
214             throw new EjenException(this,
215                     "no '" + CTX_DOM_SOURCE + "' in global context");
216         }
217         if (_foreach != null) {
218             NodeList   nl = null;
219 
220             try {
221                 ti.setParameter("root", src.getNode());
222                 nl = XPathAPI.selectNodeList(src.getNode(),
223                         evaluateAVT(ti, _foreach));
224             } catch (Exception   e) {
225                 throw new EjenException(this,
226                         "invalid 'foreach' attribute: " + _foreach, e);
227             }
228             for (int i = 0; i < nl.getLength(); i++) {
229                 DOMSource   nodeSrc = null;
230 
231                 try {
232                     nodeSrc = new DOMSource  (nl.item(i));
233                 } catch (Exception   e) {
234                     throw new EjenException(this,
235                             "invalid 'foreach' attribute: " + _foreach, e);
236                 }
237                 processTemplateStreamResult(ti, nodeSrc);
238             }
239         } else {
240             processTemplateStreamResult(ti, src);
241         }
242     }
243 
244     /**
245      * Creates the output file, based on the filepattern attribute.
246      * @param ti the TransformerImpl to use for the transformation.
247      * @param src the DOMSource to be transformed.
248      * @throws org.ejen.EjenException if something goes wrong...
249      */
250     private void processTemplateStreamResult(TransformerImpl ti, DOMSource   src) {
251         StylesheetHandler sh = null;
252 
253         try {
254             sh = (StylesheetHandler) (getFromGlobalContext(CTX_STYLESHEET_HANDLER));
255         } catch (Exception   e) {
256             throw new EjenException(this, null, e);
257         }
258         if (sh == null) {
259             throw new EjenException(this,
260                     "no '" + CTX_STYLESHEET_HANDLER + "' in context");
261         }
262         OutputStream   outputs = null;
263 
264         try {
265             StreamResult   sres = null;
266 
267             if (_filepattern != null) {
268                 // Cannot use evaluateAVT(ti, _filepattern) because _filepattern is
269                 // an AVT relative to _foreach...
270                 String   fileName = XSLUtil.evaluateAttribute(sh,
271                         ti.getXPathContext(), src.getNode(), _filepattern);
272                 boolean flag = false;
273 
274                 if (_outdated != null && _outdated.equals("true")) {
275                     flag = true;
276                 }
277                 if (!flag || outdated(fileName)) {
278                     sendMessageEvent("Creating '" + fileName + "'");
279                     File   f = new File  (fileName);
280                     File   pf = f.getParentFile();
281 
282                     if (pf != null) {
283                         pf.mkdirs();
284                     }
285                     outputs = new FileOutputStream  (f.getPath());
286                     sres = new StreamResult  (outputs);
287                 } else {
288                     return;
289                 }
290             } else {
291                 sres = new StreamResult  (new StringWriter  ());
292             }
293             ti.transform(src, sres);
294         } catch (Exception   e) {
295             throw new EjenException(this, null, e);
296         }
297         finally {
298             if (outputs != null) {
299                 try {
300                     outputs.close();
301                 } catch (Exception   e) {}
302                 finally {
303                     outputs = null;
304                 }
305             }
306         }
307     }
308     
309     /**
310      * Check if source file is newer than output file.
311      * @param fileName file name of output file.
312      */
313     protected boolean outdated(String   fileName) {
314         File   srcFile = new File  ((String  ) getFromGlobalContext("DOM_SOURCE_FILE"));
315         File   genFile = new File  (fileName);
316 
317         if (!genFile.exists() || !srcFile.exists()) { // files not exist
318             return true;
319         }
320         long slm = srcFile.lastModified(); 
321 
322         if (slm == 0L) {  // source file not exist or I/O error
323             return true;
324         }
325         long glm = genFile.lastModified();
326 
327         if (glm == 0L) { // generating file not exist
328             return true;
329         }
330         return slm >= glm;  // source file is newer than generating file
331     }
332 }
333
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