001/* SchemaFactory.java --
002   Copyright (C) 2004, 2005, 2006  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package javax.xml.validation;
039
040import java.io.BufferedReader;
041import java.io.File;
042import java.io.FileInputStream;
043import java.io.InputStream;
044import java.io.InputStreamReader;
045import java.io.IOException;
046import java.net.URL;
047import java.util.Properties;
048import javax.xml.XMLConstants;
049import javax.xml.transform.Source;
050import javax.xml.transform.stream.StreamSource;
051import org.w3c.dom.ls.LSResourceResolver;
052import org.xml.sax.ErrorHandler;
053import org.xml.sax.SAXException;
054import org.xml.sax.SAXNotRecognizedException;
055import org.xml.sax.SAXNotSupportedException;
056
057/**
058 * Factory for obtaining schemata.
059 *
060 * @author Chris Burdess (dog@gnu.org)
061 * @since 1.5
062 */
063public 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}