xml/stream/XMLOutputFactory.java

/* XMLOutputFactory.java --
   Copyright (C) 2005,2006,2009  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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independent module, the terms and conditions of the license of that
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or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
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exception statement from your version. */

package javax.xml.stream;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import java.util.Properties;
import javax.xml.transform.Result;

/**
 * Factory for obtaining XML stream and event writers for various kinds of
 * output sink.
 * <h3>Configuration</h3>
 * <table>
 * <tr>
 * <th>Name</th>
 * <th>Description</th>
 * <th>Type</th>
 * <th>Default</th>
 * <th>Required</th>
 * </tr>
 * <tr>
 * <td>javax.xml.stream.isRepairingNamespaces</td>
 * <td>default namespace prefixes</td>
 * <td>Boolean</td>
 * <td>Boolean.FALSE</td>
 * <td>yes</td>
 * </tr>
 * </table>
 */
public abstract class XMLOutputFactory
{

  /**
   * Property used to control whether to default namespace prefixes.
   * If true, the writer will create a namespace declaration for any
   * attribute that doesn't have a namespace declaration in scope.
   */
  public static final java.lang.String IS_REPAIRING_NAMESPACES =
    "javax.xml.stream.isRepairingNamespaces";

  protected XMLOutputFactory()
  {
  }

  /**
   * Creates a new <b>output</b> factory.
   * @see #newInstance(String,ClassLoader)
   */
  public static XMLOutputFactory newInstance()
    throws FactoryConfigurationError
  {
    return newInstance(null, null);
  }

  /**
   * Creates a new <b>output</b> factory.
   * The implementation class to load is the first found in the following
   * locations:
   * <ol>
   * <li>the <code>javax.xml.stream.XMLOutputFactory</code> system
   * property</li>
   * <li>the above named property value in the
   * <code><i>$JAVA_HOME</i>/lib/stax.properties</code> file</li>
   * <li>the class name specified in the
   * <code>META-INF/services/javax.xml.stream.XMLOutputFactory</code>
   * system resource</li>
   * <li>the default factory class</li>
   * </ol>
   * @param factoryId the name of the factory, same as the property
   * @param classLoader the class loader to use
   * @return a new factory instance
   * @exception FactoryConfigurationError if an instance of this factory
   * could not be loaded
   */
  public static XMLOutputFactory newInstance(String factoryId,
                                             ClassLoader classLoader)
    throws FactoryConfigurationError
  {
    if (classLoader == null)
      {
        classLoader = Thread.currentThread().getContextClassLoader();
      }
    if (classLoader == null)
      {
        classLoader = XMLOutputFactory.class.getClassLoader();
      }
    String className = null;
    int count = 0;
    do
      {
        className = getFactoryClassName(classLoader, count++);
        if (className != null)
          {
            try
              {
                Class<?> t = (classLoader != null) ?
                  classLoader.loadClass(className) :
                  Class.forName(className);
                return (XMLOutputFactory) t.newInstance();
              }
            catch (ClassNotFoundException e)
              {
                className = null;
              }
            catch (Exception e)
              {
                throw new FactoryConfigurationError(e,
                     "error instantiating class " + className);
              }
          }
      }
    while (className == null && count < 3);
    return new gnu.xml.stream.XMLOutputFactoryImpl();
  }

  private static String getFactoryClassName(ClassLoader loader, int attempt)
  {
    final String propertyName = "javax.xml.stream.XMLOutputFactory";
    switch (attempt)
      {
        case 0:
          return System.getProperty(propertyName);
        case 1:
          try
            {
              File file = new File(System.getProperty("java.home"));
              file = new File(file, "lib");
              file = new File(file, "stax.properties");
              InputStream in = new FileInputStream(file);
              Properties props = new Properties();
              props.load(in);
              in.close();
              return props.getProperty(propertyName);
            }
          catch (IOException e)
            {
              return null;
            }
        case 2:
          try
            {
              String serviceKey = "/META-INF/services/" + propertyName;
              InputStream in = (loader != null) ?
                 loader.getResourceAsStream(serviceKey) :
                XMLOutputFactory.class.getResourceAsStream(serviceKey);
              if (in != null)
                {
                  BufferedReader r =
                     new BufferedReader(new InputStreamReader(in));
                  String ret = r.readLine();
                  r.close();
                  return ret;
                }
            }
          catch (IOException e)
            {
            }
          return null;
        default:
          return null;
      }
  }

  /**
   * Creates a new stream writer.
   */
  public abstract XMLStreamWriter createXMLStreamWriter(Writer stream)
    throws XMLStreamException;

  /**
   * Creates a new stream writer.
   */
  public abstract XMLStreamWriter createXMLStreamWriter(OutputStream stream)
    throws XMLStreamException;

  /**
   * Creates a new stream writer.
   */
  public abstract XMLStreamWriter createXMLStreamWriter(OutputStream stream,
                                                        String encoding)
    throws XMLStreamException;

  /**
   * Creates a new stream writer.
   * @exception UnsupportedOperationException if this method is not
   * supported
   */
  public abstract XMLStreamWriter createXMLStreamWriter(Result result)
    throws XMLStreamException;

  /**
   * Creates a new event writer.
   * @exception UnsupportedOperationException if this method is not
   * supported
   */
  public abstract XMLEventWriter createXMLEventWriter(Result result)
    throws XMLStreamException;

  /**
   * Creates a new event writer.
   */
  public abstract XMLEventWriter createXMLEventWriter(OutputStream stream)
    throws XMLStreamException;

  /**
   * Creates a new event writer.
   */
  public abstract XMLEventWriter createXMLEventWriter(OutputStream stream,
                                                      String encoding)
    throws XMLStreamException;

  /**
   * Creates a new event writer.
   */
  public abstract XMLEventWriter createXMLEventWriter(Writer stream)
    throws XMLStreamException;

  /**
   * Sets the implementation-specific property of the given name.
   * @exception IllegalArgumentException if the property is not supported
   */
  public abstract void setProperty(String name, Object value)
    throws IllegalArgumentException;

  /**
   * Returns the implementation-specific property of the given name.
   * @exception IllegalArgumentException if the property is not supported
   */
  public abstract Object getProperty(String name)
    throws IllegalArgumentException;

  /**
   * Indicates whether the specified property is supported.
   */
  public abstract boolean isPropertySupported(String name);

}