001    /* SchemaFactory.java -- 
002       Copyright (C) 2004, 2005, 2006  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.validation;
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.net.URL;
047    import java.util.Properties;
048    import javax.xml.XMLConstants;
049    import javax.xml.transform.Source;
050    import javax.xml.transform.stream.StreamSource;
051    import org.w3c.dom.ls.LSResourceResolver;
052    import org.xml.sax.ErrorHandler;
053    import org.xml.sax.SAXException;
054    import org.xml.sax.SAXNotRecognizedException;
055    import org.xml.sax.SAXNotSupportedException;
056    
057    /**
058     * Factory for obtaining schemata.
059     *
060     * @author Chris Burdess (dog@gnu.org)
061     * @since 1.5
062     */
063    public abstract class SchemaFactory
064    {
065      protected SchemaFactory()
066      {
067      }
068    
069      /**
070       * Returns an implementation of <code>SchemaFactory</code> that supports
071       * the specified schema language.
072       * @param schemaLanguage the URI of a schema language (see
073       * <code>XMLConstants</code>)
074       */
075      public static final SchemaFactory newInstance(String schemaLanguage)
076      {
077        ClassLoader loader = Thread.currentThread().getContextClassLoader();
078        if (loader == null)
079          {
080            loader = SchemaFactory.class.getClassLoader();
081          }
082        final String factoryClassName = "javax.xml.validation.SchemaFactory";
083        String className = null;
084        int count = 0;
085        do
086          {
087            className = getFactoryClassName(loader, schemaLanguage, count++);
088            if (className != null)
089              {
090                try
091                  {
092                    Class<?> t = (loader != null) ? loader.loadClass(className) :
093                        Class.forName(className);
094                    return (SchemaFactory) t.newInstance();
095                  }
096                catch (Exception e)
097                  {
098                    // Ignore any errors and continue algorithm.
099                    // This method doesn't have a means of propagating
100                    // class instantiation errors.
101                    className = null;
102                  }
103            }
104        }
105        while (className == null && count < 2);
106        try
107          {
108            String serviceKey = "/META-INF/services/" + factoryClassName;
109            InputStream in = (loader != null) ?
110              loader.getResourceAsStream(serviceKey) :
111              SchemaFactory.class.getResourceAsStream(serviceKey);
112            if (in != null)
113              {
114                BufferedReader r =
115                  new BufferedReader(new InputStreamReader(in));
116                try
117                  {
118                    for (String line = r.readLine(); line != null;
119                            line = r.readLine())
120                      {
121                        Class<?> t = (loader != null) ? loader.loadClass(className) :
122                            Class.forName(className);
123                        SchemaFactory ret = (SchemaFactory) t.newInstance();
124                        if (ret.isSchemaLanguageSupported(schemaLanguage))
125                          return ret;
126                      }
127                  }
128                catch (Exception e)
129                  {
130                    // Fall through. See above.
131                  }
132                finally
133                  {
134                    r.close();
135                  }
136              }
137          }
138        catch (IOException e)
139          {
140          }
141        // Default schema factories for Classpath
142        if (XMLConstants.W3C_XML_SCHEMA_NS_URI.equals(schemaLanguage))
143          return new gnu.xml.validation.xmlschema.XMLSchemaSchemaFactory();
144        if (XMLConstants.RELAXNG_NS_URI.equals(schemaLanguage))
145          return new gnu.xml.validation.relaxng.RELAXNGSchemaFactory();
146        throw new IllegalArgumentException(schemaLanguage);
147      }
148    
149      private static String getFactoryClassName(ClassLoader loader,
150              String schemaLanguage, int attempt)
151      {
152        final String factoryClassName = "javax.xml.validation.SchemaFactory";
153        final String propertyName = factoryClassName + ":" + schemaLanguage;
154        switch (attempt)
155          {
156            case 0:
157              return System.getProperty(propertyName);
158            case 1:
159              try
160                {
161                  File file = new File(System.getProperty("java.home"));
162                  file = new File(file, "lib");
163                  file = new File(file, "jaxp.properties");
164                  InputStream in = new FileInputStream(file);
165                  Properties props = new Properties();
166                  props.load(in);
167                  in.close();
168                  return props.getProperty(propertyName);
169                }
170              catch (IOException e)
171                {
172                  return null;
173                }
174            default:
175              return null;
176          }
177      }
178    
179      /**
180       * Indicates whether the specified schema language is supported.
181       * @param schemaLanguage the URI of a schema language (see
182       * <code>XMLConstants</code>)
183       */
184      public abstract boolean isSchemaLanguageSupported(String schemaLanguage);
185    
186      public boolean getFeature(String name)
187        throws SAXNotRecognizedException, SAXNotSupportedException
188      {
189        throw new SAXNotRecognizedException(name);
190      }
191      
192      public void setFeature(String name, boolean value)
193        throws SAXNotRecognizedException, SAXNotSupportedException
194      {
195        throw new SAXNotRecognizedException(name);
196      }
197      
198      public Object getProperty(String name)
199        throws SAXNotRecognizedException, SAXNotSupportedException
200      {
201        throw new SAXNotRecognizedException(name);
202      }
203      
204      public void setProperty(String name, Object value)
205        throws SAXNotRecognizedException, SAXNotSupportedException
206      {
207        throw new SAXNotRecognizedException(name);
208      }
209      
210      public abstract ErrorHandler getErrorHandler();
211      
212      public abstract void setErrorHandler(ErrorHandler errorHandler);
213    
214      public abstract LSResourceResolver getResourceResolver();
215    
216      public abstract void setResourceResolver(LSResourceResolver resourceResolver);
217      
218      /**
219       * Returns a schema based on the specified source resource.
220       * @param schema the source resource
221       */
222      public Schema newSchema(Source schema)
223        throws SAXException
224      {
225        return newSchema(new Source[] { schema });
226      }
227    
228      /**
229       * Returns a schema based on the specified source file.
230       * @param schema the source resource
231       */
232      public Schema newSchema(File schema)
233        throws SAXException
234      {
235        return newSchema(new StreamSource(schema));
236      }
237      
238      /**
239       * Returns a schema based on the specified URL.
240       * @param schema the source resource
241       */
242      public Schema newSchema(URL schema)
243        throws SAXException
244      {
245        return newSchema(new StreamSource(schema.toString()));
246      }
247      
248      /**
249       * Parses the specified sources, and combine them into a single schema.
250       * The exact procedure and semantics of this depends on the schema
251       * language.
252       * @param schemata the schema resources to load
253       */
254      public abstract Schema newSchema(Source[] schemata)
255        throws SAXException;
256      
257      /**
258       * Creates a special schema.
259       * The exact semantics of this depends on the schema language.
260       */
261      public abstract Schema newSchema()
262        throws SAXException;
263      
264    }