001    /* SAXParserFactory.java -- 
002       Copyright (C) 2004, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    package javax.xml.parsers;
039    
040    import java.io.BufferedReader;
041    import java.io.File;
042    import java.io.FileInputStream;
043    import java.io.InputStream;
044    import java.io.InputStreamReader;
045    import java.io.IOException;
046    import java.util.Properties;
047    import javax.xml.validation.Schema;
048    import org.xml.sax.SAXException;
049    import org.xml.sax.SAXNotRecognizedException;
050    import org.xml.sax.SAXNotSupportedException;
051    
052    /**
053     * Factory for obtaining SAX parsers.
054     * Instances of this class are <em>not</em> guaranteed to be thread safe.
055     *
056     * @author (a href='mailto:dog@gnu.org'>Chris Burdess</a)
057     */
058    public abstract class SAXParserFactory
059    {
060    
061      private boolean validating;
062      private boolean namespaceAware;
063      private Schema schema;
064      private boolean xIncludeAware;
065    
066      protected SAXParserFactory()
067      {
068      }
069    
070      /**
071       * Creates a new factory instance.
072       * The implementation class to load is the first found in the following
073       * locations:
074       * <ol>
075       * <li>the <code>javax.xml.parsers.SAXParserFactory</code> system
076       * property</li>
077       * <li>the above named property value in the
078       * <code><i>$JAVA_HOME</i>/lib/jaxp.properties</code> file</li>
079       * <li>the class name specified in the
080       * <code>META-INF/services/javax.xml.parsers.SAXParserFactory</code>
081       * system resource</li>
082       * <li>the default factory class</li>
083       * </ol>
084       */
085      public static SAXParserFactory newInstance()
086        throws FactoryConfigurationError
087      {
088        ClassLoader loader = Thread.currentThread().getContextClassLoader();
089        if (loader == null)
090          {
091            loader = SAXParserFactory.class.getClassLoader();
092          }
093        String className = null;
094        int count = 0;
095        do
096          {
097            className = getFactoryClassName(loader, count++);
098            if (className != null)
099              {
100                try
101                  {
102                    Class<?> t = (loader != null) ? loader.loadClass(className) :
103                      Class.forName(className);
104                    return (SAXParserFactory) t.newInstance();
105                  }
106                catch (ClassNotFoundException e)
107                  {
108                    className = null;
109                  }
110                catch (Exception e)
111                  {
112                    throw new FactoryConfigurationError(e,
113                         "error instantiating class " + className);
114                  }
115              }
116          }
117        while (className == null && count < 3);
118        return new gnu.xml.stream.SAXParserFactory();
119      }
120    
121      private static String getFactoryClassName(ClassLoader loader, int attempt)
122      {
123        final String propertyName = "javax.xml.parsers.SAXParserFactory";
124        switch (attempt)
125          {
126            case 0:
127              return System.getProperty(propertyName);
128            case 1:
129              try
130                {
131                  File file = new File(System.getProperty("java.home"));
132                  file = new File(file, "lib");
133                  file = new File(file, "jaxp.properties");
134                  InputStream in = new FileInputStream(file);
135                  Properties props = new Properties();
136                  props.load(in);
137                  in.close();
138                  return props.getProperty(propertyName);
139                }
140              catch (IOException e)
141                {
142                  return null;
143                }
144            case 2:
145              try
146                {
147                  String serviceKey = "/META-INF/services/" + propertyName;
148                  InputStream in = (loader != null) ?
149                     loader.getResourceAsStream(serviceKey) :
150                    SAXParserFactory.class.getResourceAsStream(serviceKey);
151                  if (in != null)
152                    {
153                      BufferedReader r =
154                         new BufferedReader(new InputStreamReader(in));
155                      String ret = r.readLine();
156                      r.close();
157                      return ret;
158                    }
159                }
160              catch (IOException e)
161                {
162                }
163              return null;
164            default:
165              return null;
166          }
167      }
168    
169      /**
170       * Creates a new parser instance using the currently specified factory
171       * configuration.
172       * @exception ParserConfigurationException if the specified configuration
173       * is not supported
174       */
175      public abstract SAXParser newSAXParser()
176        throws ParserConfigurationException, SAXException;
177    
178      /**
179       * Sets whether parsers obtained from this factory will be XML Namespace
180       * aware.
181       */
182      public void setNamespaceAware(boolean awareness)
183      {
184        namespaceAware = awareness;
185      }
186    
187      /**
188       * Sets whether parsers obtained from this factory will validate their
189       * input.
190       */
191      public void setValidating(boolean validating)
192      {
193        this.validating = validating;
194      }
195    
196      /**
197       * Indicates whether parsers obtained from this factory will be XML
198       * Namespace aware.
199       */
200      public boolean isNamespaceAware()
201      {
202        return namespaceAware;
203      }
204    
205      /**
206       * Indicates whether parsers obtained from this factory will validate
207       * their input.
208       */
209      public boolean isValidating()
210      {
211        return validating;
212      }
213    
214      /**
215       * Sets the specified feature for SAX2 parsers obtained from this factory.
216       * @param name the feature name
217       * @param value the featurevalue
218       */
219      public abstract void setFeature(String name, boolean value) 
220        throws ParserConfigurationException, SAXNotRecognizedException, 
221               SAXNotSupportedException;
222    
223      /**
224       * Returns the specified feature for SAX2 parsers obtained from this
225       * factory.
226       * @param name the feature name
227       */
228      public abstract boolean getFeature(String name) 
229        throws ParserConfigurationException, SAXNotRecognizedException, 
230               SAXNotSupportedException;
231    
232      // -- JAXP 1.3 methods --
233    
234      /**
235       * Returns the schema.
236       * @since 1.3
237       * @see #setSchema
238       */
239      public Schema getSchema()
240      {
241        return schema;
242      }
243    
244      /**
245       * Sets the schema.
246       * @since 1.3
247       * @see #getSchema
248       */
249      public void setSchema(Schema schema)
250      {
251        this.schema = schema;
252      }
253    
254      /**
255       * Indicates whether parsers obtained from this factory will be XInclude
256       * aware.
257       * @since 1.3
258       */
259      public boolean isXIncludeAware()
260      {
261        return xIncludeAware;
262      }
263    
264      /**
265       * Sets whether parsers obtained from this factory will be XInclude aware.
266       * @since 1.3
267       */
268      public void setXIncludeAware(boolean state)
269      {
270        xIncludeAware = state;
271      }
272    
273    }