XmlParser


1   /*
2    * $Id: XmlParser.java 54929 2004-10-16 16:38:42Z germuska $ 
3    *
4    * Copyright 1999-2004 The Apache Software Foundation.
5    * 
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * You may obtain a copy of the License at
9    * 
10   *      http://www.apache.org/licenses/LICENSE-2.0
11   * 
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  
20  package org.apache.struts.tiles.xmlDefinition;
21  
22  import java.io.BufferedInputStream  ;
23  import java.io.FileInputStream  ;
24  import java.io.IOException  ;
25  import java.io.InputStream  ;
26  import java.net.URL  ;
27  
28  import org.apache.commons.digester.Digester;
29  import org.xml.sax.SAXException  ;
30  
31  /**
32   * Parse an XML definitions file.
33   */
34  public class XmlParser
35  {
36  
37      /** Associated digester. */
38    protected Digester digester;
39      /**
40       * Should we use a validating XML parser to read the configuration file.
41       * Default is <code>false</code>.
42       */
43      protected boolean validating = false;
44      /**
45       * The set of public identifiers, and corresponding resource names for
46       * the versions of the configuration file DTDs we know about.  There
47       * <strong>MUST</strong> be an even number of Strings in this list!
48       */
49      protected String   registrations[] = {
50          "-//Apache Software Foundation//DTD Tiles Configuration 1.1//EN",
51          "/org/apache/struts/resources/tiles-config_1_1.dtd",
52      };
53  
54       /**
55        * Constructor.
56        * Creates a digester parser and initializes syntax rules.
57        */
58    public XmlParser()
59    {
60      digester = new Digester();
61      digester.setValidating(validating);
62      digester.setNamespaceAware(true);
63      digester.setUseContextClassLoader(true);
64      // Register our local copy of the DTDs that we can find
65    for (int i = 0; i < registrations.length; i += 2) {
66        URL   url = this.getClass().getResource(registrations[i+1]);
67        if (url != null)
68            {
69            digester.register(registrations[i], url.toString());
70            }
71    }
72      // Init syntax rules
73    initDigester( digester );
74    }
75  
76      /**
77       * Set digester validating flag.
78       */
79    public void setValidating( boolean validating )
80      {
81      digester.setValidating( validating);
82      }
83  
84  
85     /**
86      * Init digester for components syntax.
87      * This is an old set of rules, left for backward compatibility.
88      * @param digester Digester instance to use.
89      */
90    private void initDigesterForComponentsDefinitionsSyntax( Digester digester )
91    {
92       // Common constants
93    String   PACKAGE_NAME = "org.apache.struts.tiles.xmlDefinition";
94    String   DEFINITION_TAG = "component-definitions/definition";
95    String   definitionHandlerClass = PACKAGE_NAME + ".XmlDefinition";
96  
97    String   PUT_TAG  = DEFINITION_TAG + "/put";
98    String   putAttributeHandlerClass = PACKAGE_NAME + ".XmlAttribute";
99  
100   String   LIST_TAG = DEFINITION_TAG + "/putList";
101   String   listHandlerClass     = PACKAGE_NAME + ".XmlListAttribute";
102 
103   String   ADD_LIST_ELE_TAG = LIST_TAG + "/add";
104 
105     // syntax rules
106     digester.addObjectCreate(  DEFINITION_TAG, definitionHandlerClass );
107     digester.addSetProperties( DEFINITION_TAG);
108     digester.addSetNext(       DEFINITION_TAG, "putDefinition", definitionHandlerClass);
109     // put / putAttribute rules
110     digester.addObjectCreate(  PUT_TAG, putAttributeHandlerClass);
111     digester.addSetNext(       PUT_TAG, "addAttribute", putAttributeHandlerClass);
112     digester.addSetProperties( PUT_TAG);
113     digester.addCallMethod(    PUT_TAG, "setBody", 0);
114     // list rules
115     digester.addObjectCreate(  LIST_TAG, listHandlerClass);
116     digester.addSetProperties( LIST_TAG);
117     digester.addSetNext(       LIST_TAG, "addAttribute", putAttributeHandlerClass);
118     // list elements rules
119     // We use Attribute class to avoid rewriting a new class.
120     // Name part can't be used in listElement attribute.
121     digester.addObjectCreate(  ADD_LIST_ELE_TAG, putAttributeHandlerClass);
122     digester.addSetNext(       ADD_LIST_ELE_TAG, "add", putAttributeHandlerClass);
123     digester.addSetProperties( ADD_LIST_ELE_TAG);
124     digester.addCallMethod(    ADD_LIST_ELE_TAG, "setBody", 0);
125   }
126 
127    /**
128     * Init digester for Tiles syntax.
129     * Same as components, but with first element = tiles-definitions
130     * @param digester Digester instance to use.
131     */
132   private void initDigesterForTilesDefinitionsSyntax( Digester digester )
133   {
134      // Common constants
135   String   PACKAGE_NAME = "org.apache.struts.tiles.xmlDefinition";
136   String   DEFINITION_TAG = "tiles-definitions/definition";
137   String   definitionHandlerClass = PACKAGE_NAME + ".XmlDefinition";
138 
139   String   PUT_TAG  = DEFINITION_TAG + "/put";
140   String   putAttributeHandlerClass = PACKAGE_NAME + ".XmlAttribute";
141 
142   //String LIST_TAG = DEFINITION_TAG + "/putList";
143     // List tag value
144   String   LIST_TAG = "putList";
145   String   DEF_LIST_TAG = DEFINITION_TAG + "/" + LIST_TAG;
146   String   listHandlerClass     = PACKAGE_NAME + ".XmlListAttribute";
147     // Tag value for adding an element in a list
148   String   ADD_LIST_ELE_TAG = "*/" + LIST_TAG + "/add";
149 
150     // syntax rules
151     digester.addObjectCreate(  DEFINITION_TAG, definitionHandlerClass );
152     digester.addSetProperties( DEFINITION_TAG);
153     digester.addSetNext(       DEFINITION_TAG, "putDefinition", definitionHandlerClass);
154     // put / putAttribute rules
155     // Rules for a same pattern are called in order, but rule.end() are called
156     // in reverse order.
157     // SetNext and CallMethod use rule.end() method. So, placing SetNext in
158     // first position ensure it will be called last (sic).
159     digester.addObjectCreate(  PUT_TAG, putAttributeHandlerClass);
160     digester.addSetNext(       PUT_TAG, "addAttribute", putAttributeHandlerClass);
161     digester.addSetProperties( PUT_TAG);
162     digester.addCallMethod(    PUT_TAG, "setBody", 0);
163     // Definition level list rules
164     // This is rules for lists nested in a definition
165     digester.addObjectCreate(  DEF_LIST_TAG, listHandlerClass);
166     digester.addSetProperties( DEF_LIST_TAG);
167     digester.addSetNext(       DEF_LIST_TAG, "addAttribute", putAttributeHandlerClass);
168     // list elements rules
169     // We use Attribute class to avoid rewriting a new class.
170     // Name part can't be used in listElement attribute.
171     digester.addObjectCreate(  ADD_LIST_ELE_TAG, putAttributeHandlerClass);
172     digester.addSetNext(       ADD_LIST_ELE_TAG, "add", putAttributeHandlerClass);
173     digester.addSetProperties( ADD_LIST_ELE_TAG);
174     digester.addCallMethod(    ADD_LIST_ELE_TAG, "setBody", 0);
175 
176     // nested list elements rules
177     // Create a list handler, and add it to parent list
178   String   NESTED_LIST = "*/" + LIST_TAG + "/" + LIST_TAG;
179     digester.addObjectCreate(  NESTED_LIST, listHandlerClass);
180     digester.addSetProperties( NESTED_LIST);
181     digester.addSetNext(       NESTED_LIST, "add", putAttributeHandlerClass);
182 
183     // item elements rules
184     // We use Attribute class to avoid rewriting a new class.
185     // Name part can't be used in listElement attribute.
186   //String ADD_WILDCARD = LIST_TAG + "/addItem";
187   // non String ADD_WILDCARD = LIST_TAG + "/addx*";
188   String   ADD_WILDCARD = "*/item";
189   String   menuItemDefaultClass = "org.apache.struts.tiles.beans.SimpleMenuItem";
190     digester.addObjectCreate(  ADD_WILDCARD, menuItemDefaultClass, "classtype");
191     digester.addSetNext(       ADD_WILDCARD, "add", "java.lang.Object");
192     digester.addSetProperties( ADD_WILDCARD);
193 
194     // bean elements rules
195   String   BEAN_TAG = "*/bean";
196   String   beanDefaultClass = "org.apache.struts.tiles.beans.SimpleMenuItem";
197     digester.addObjectCreate(  BEAN_TAG, beanDefaultClass, "classtype");
198     digester.addSetNext(       BEAN_TAG, "add", "java.lang.Object");
199     digester.addSetProperties( BEAN_TAG);
200 
201     // Set properties to surrounding element
202   digester.addSetProperty(BEAN_TAG+ "/set-property", "property", "value");
203   }
204 
205    /**
206     * Init digester in order to parse instances definition file syntax.
207     * Instances is an old name for "definition". This method is left for
208     * backwards compatibility.
209     * @param digester Digester instance to use.
210     */
211   private void initDigesterForInstancesSyntax( Digester digester )
212   {
213         // Build a digester to process our configuration resource
214   String   PACKAGE_NAME = "org.apache.struts.tiles.xmlDefinition";
215   String   INSTANCE_TAG = "component-instances/instance";
216   String   instanceHandlerClass = PACKAGE_NAME + ".XmlDefinition";
217 
218   String   PUT_TAG = INSTANCE_TAG + "/put";
219   String   PUTATTRIBUTE_TAG = INSTANCE_TAG + "/putAttribute";
220   String   putAttributeHandlerClass = PACKAGE_NAME + ".XmlAttribute";
221 
222   String   LIST_TAG     = INSTANCE_TAG + "/putList";
223   String   listHandlerClass     = PACKAGE_NAME + ".XmlListAttribute";
224 
225   String   ADD_LIST_ELE_TAG = LIST_TAG + "/add";
226 
227     // component instance rules
228     digester.addObjectCreate(  INSTANCE_TAG, instanceHandlerClass );
229     digester.addSetProperties( INSTANCE_TAG);
230     digester.addSetNext(       INSTANCE_TAG, "putDefinition", instanceHandlerClass);
231     // put / putAttribute rules
232     digester.addObjectCreate(  PUTATTRIBUTE_TAG, putAttributeHandlerClass);
233     digester.addSetProperties( PUTATTRIBUTE_TAG);
234     digester.addSetNext(       PUTATTRIBUTE_TAG, "addAttribute", putAttributeHandlerClass);
235     // put / putAttribute rules
236     digester.addObjectCreate(  PUT_TAG, putAttributeHandlerClass);
237     digester.addSetProperties( PUT_TAG);
238     digester.addSetNext(       PUT_TAG, "addAttribute", putAttributeHandlerClass);
239     // list rules
240     digester.addObjectCreate(  LIST_TAG, listHandlerClass);
241     digester.addSetProperties( LIST_TAG);
242     digester.addSetNext(       LIST_TAG, "addAttribute", putAttributeHandlerClass);
243     // list elements rules
244     // We use Attribute class to avoid rewriting a new class.
245     // Name part can't be used in listElement attribute.
246     digester.addObjectCreate(  ADD_LIST_ELE_TAG, putAttributeHandlerClass);
247     digester.addSetProperties( ADD_LIST_ELE_TAG);
248     digester.addSetNext(       ADD_LIST_ELE_TAG, "add", putAttributeHandlerClass);
249   }
250 
251    /**
252     * Init digester.
253     * @param digester Digester instance to use.
254     */
255   protected void initDigester( Digester digester )
256   {
257   initDigesterForTilesDefinitionsSyntax( digester );
258   initDigesterForComponentsDefinitionsSyntax( digester );
259   initDigesterForInstancesSyntax( digester );
260   }
261 
262   /**
263    * Parse input reader and add encountered definitions to definitions set.
264    * @param in Input stream.
265    * @param definitions Xml Definitions set to which encountered definition are added.
266    * @throws IOException On errors during file parsing.
267    * @throws SAXException On errors parsing XML.
268    */
269   public void parse( InputStream   in, XmlDefinitionsSet definitions ) throws IOException  , SAXException  
270   {
271     try
272     {
273       // set first object in stack
274     //digester.clear();
275     digester.push(definitions);
276       // parse
277       digester.parse(in);
278       in.close();
279       }
280   catch (SAXException   e)
281     {
282       //throw new ServletException( "Error while parsing " + mappingConfig, e);
283     throw e;
284       }
285 
286   }
287 
288     /**
289      * Main method to check file syntax.
290      */
291   public static void main(String  [] args)
292   {
293   //String filename = "E:/programs/jakarta-tomcat/webapps/wtiles-struts/WEB-INF/tiles-examples-defs.xml";
294   String   filename = "E:/programs/jakarta-tomcat-4.0.3/webapps/wtiles-struts/WEB-INF/tiles-examples-defs.xml";
295   //String filename = "E:/programs/jakarta-tomcat/webapps/wtiles-struts/WEB-INF/tilesDefinitions.xml";
296   //String filename = "E:/programs/jakarta-tomcat/webapps/wtiles-channel/WEB-INF/componentDefinitions.xml";
297   //String filename2 = "E:/programs/jakarta-tomcat/webapps/wtiles-tutorial/WEB-INF/componentDefinitions.xml";
298 
299 
300     if( args.length > 1 )
301       {
302       filename = args[1];
303       } // end if
304 
305   System.out.println( "Read file '" + filename  +"'" );
306 
307   InputStream   input = null;
308   // InputStream input2 = null;
309     // Open file
310     try
311       {
312         input = new BufferedInputStream  (
313                              new FileInputStream  ( filename) );
314     //    input2 = new BufferedInputStream(
315           //                   new FileInputStream( filename2) );
316       }
317      catch( IOException   ex )
318       {
319       System.out.println( "can't open file '" + filename + "' : " + ex.getMessage() );
320       }
321     // Check file syntax
322     try
323       {
324         XmlParser parser = new XmlParser();
325       parser.setValidating(true);
326       XmlDefinitionsSet definitions = new XmlDefinitionsSet();
327         System.out.println( "  Parse file" );
328       parser.parse( input, definitions);
329       //  System.out.println( "  Check file 2" );
330       //parser.parse( input2, definitions);
331         System.out.println( "  done." );
332       System.out.println( "  Result : " + definitions.toString() );
333       }
334      catch( Exception   ex )
335       {
336       System.out.println( "Error during parsing '" + filename + "' : " + ex.getMessage() );
337       ex.printStackTrace();
338       }
339   }
340 
341 }
342
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