org.osgi.compendium/src/main/java/org/osgi/util/xml/XMLParserActivator.java - onos-felix - Gitiles

 /*
  * $Header: /cvshome/build/org.osgi.util.xml/src/org/osgi/util/xml/XMLParserActivator.java,v 1.8 2006/03/14 01:21:37 hargrave Exp $
  *
  * Copyright (c) OSGi Alliance (2002, 2005). All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package org.osgi.util.xml;

 import java.io.*;
 import java.net.URL;
 import java.util.*;

 import javax.xml.parsers.*;

 import org.osgi.framework.*;

 /**
  * A BundleActivator class that allows any JAXP compliant XML Parser to register
  * itself as an OSGi parser service.
  *
  * Multiple JAXP compliant parsers can concurrently register by using this
  * BundleActivator class. Bundles who wish to use an XML parser can then use the
  * framework's service registry to locate available XML Parsers with the desired
  * characteristics such as validating and namespace-aware.
  *
  * <p>
  * The services that this bundle activator enables a bundle to provide are:
  * <ul>
  * <li><code>javax.xml.parsers.SAXParserFactory</code>({@link #SAXFACTORYNAME})
  * <li><code>javax.xml.parsers.DocumentBuilderFactory</code>(
  * {@link #DOMFACTORYNAME})
  * </ul>
  *
  * <p>
  * The algorithm to find the implementations of the abstract parsers is derived
  * from the JAR file specifications, specifically the Services API.
  * <p>
  * An XMLParserActivator assumes that it can find the class file names of the
  * factory classes in the following files:
  * <ul>
  * <li><code>/META-INF/services/javax.xml.parsers.SAXParserFactory</code> is
  * a file contained in a jar available to the runtime which contains the
  * implementation class name(s) of the SAXParserFactory.
  * <li><code>/META-INF/services/javax.xml.parsers.DocumentBuilderFactory</code>
  * is a file contained in a jar available to the runtime which contains the
  * implementation class name(s) of the <code>DocumentBuilderFactory</code>
  * </ul>
  * <p>
  * If either of the files does not exist, <code>XMLParserActivator</code>
  * assumes that the parser does not support that parser type.
  *
  * <p>
  * <code>XMLParserActivator</code> attempts to instantiate both the
  * <code>SAXParserFactory</code> and the <code>DocumentBuilderFactory</code>.
  * It registers each factory with the framework along with service properties:
  * <ul>
  * <li>{@link #PARSER_VALIDATING}- indicates if this factory supports
  * validating parsers. It's value is a <code>Boolean</code>.
  * <li>{@link #PARSER_NAMESPACEAWARE}- indicates if this factory supports
  * namespace aware parsers It's value is a <code>Boolean</code>.
  * </ul>
  * <p>
  * Individual parser implementations may have additional features, properties,
  * or attributes which could be used to select a parser with a filter. These can
  * be added by extending this class and overriding the
  * <code>setSAXProperties</code> and <code>setDOMProperties</code> methods.
  */
 public class XMLParserActivator implements BundleActivator, ServiceFactory {
 	/** Context of this bundle */
 	private BundleContext		context;
 	/**
 	 * Filename containing the SAX Parser Factory Class name. Also used as the
 	 * basis for the <code>SERVICE_PID<code> registration property.
 	 */
 	public static final String	SAXFACTORYNAME			= "javax.xml.parsers.SAXParserFactory";
 	/**
 	 * Filename containing the DOM Parser Factory Class name. Also used as the
 	 * basis for the <code>SERVICE_PID</code> registration property.
 	 */
 	public static final String	DOMFACTORYNAME			= "javax.xml.parsers.DocumentBuilderFactory";
 	/** Path to the factory class name files */
 	private static final String	PARSERCLASSFILEPATH		= "/META-INF/services/";
 	/** Fully qualified path name of SAX Parser Factory Class Name file */
 	public static final String	SAXCLASSFILE			= PARSERCLASSFILEPATH
 																+ SAXFACTORYNAME;
 	/** Fully qualified path name of DOM Parser Factory Class Name file */
 	public static final String	DOMCLASSFILE			= PARSERCLASSFILEPATH
 																+ DOMFACTORYNAME;
 	/** SAX Factory Service Description */
 	private static final String	SAXFACTORYDESCRIPTION	= "A JAXP Compliant SAX Parser";
 	/** DOM Factory Service Description */
 	private static final String	DOMFACTORYDESCRIPTION	= "A JAXP Compliant DOM Parser";
 	/**
 	 * Service property specifying if factory is configured to support
 	 * validating parsers. The value is of type <code>Boolean</code>.
 	 */
 	public static final String	PARSER_VALIDATING		= "parser.validating";
 	/**
 	 * Service property specifying if factory is configured to support namespace
 	 * aware parsers. The value is of type <code>Boolean</code>.
 	 */
 	public static final String	PARSER_NAMESPACEAWARE	= "parser.namespaceAware";
 	/**
 	 * Key for parser factory name property - this must be saved in the parsers
 	 * properties hashtable so that the parser factory can be instantiated from
 	 * a ServiceReference
 	 */
 	private static final String	FACTORYNAMEKEY			= "parser.factoryname";

 	/**
 	 * Called when this bundle is started so the Framework can perform the
 	 * bundle-specific activities necessary to start this bundle. This method
 	 * can be used to register services or to allocate any resources that this
 	 * bundle needs.
 	 *
 	 * <p>
 	 * This method must complete and return to its caller in a timely manner.
 	 *
 	 * <p>
 	 * This method attempts to register a SAX and DOM parser with the
 	 * Framework's service registry.
 	 *
 	 * @param context The execution context of the bundle being started.
 	 * @throws java.lang.Exception If this method throws an exception, this
 	 *         bundle is marked as stopped and the Framework will remove this
 	 *         bundle's listeners, unregister all services registered by this
 	 *         bundle, and release all services used by this bundle.
 	 * @see Bundle#start
 	 */
 	public void start(BundleContext context) throws Exception {
 		this.context = context;
 		Bundle parserBundle = context.getBundle();
 		try {
 			// check for sax parsers
 			registerSAXParsers(getParserFactoryClassNames(parserBundle
 					.getResource(SAXCLASSFILE)));
 			// check for dom parsers
 			registerDOMParsers(getParserFactoryClassNames(parserBundle
 					.getResource(DOMCLASSFILE)));
 		}
 		catch (IOException ioe) {
 			// if there were any IO errors accessing the resource files
 			// containing the class names
 			ioe.printStackTrace();
 			throw new FactoryConfigurationError(ioe);
 		}
 	}

 	/**
 	 * <p>
 	 * This method has nothing to do as all active service registrations will
 	 * automatically get unregistered when the bundle stops.
 	 *
 	 * @param context The execution context of the bundle being stopped.
 	 * @throws java.lang.Exception If this method throws an exception, the
 	 *         bundle is still marked as stopped, and the Framework will remove
 	 *         the bundle's listeners, unregister all services registered by the
 	 *         bundle, and release all services used by the bundle.
 	 * @see Bundle#stop
 	 */
 	public void stop(BundleContext context) throws Exception {
 	}

 	/**
 	 * Given the URL for a file, reads and returns the parser class names. There
 	 * may be multiple classes specified in this file, one per line. There may
 	 * also be comment lines in the file, which begin with "#".
 	 *
 	 * @param parserUrl The URL of the service file containing the parser class
 	 *        names
 	 * @return A vector of strings containing the parser class names or null if
 	 *         parserUrl is null
 	 * @throws IOException if there is a problem reading the URL input stream
 	 */
 	private Vector getParserFactoryClassNames(URL parserUrl) throws IOException {
 		Vector v = new Vector(1);
 		if (parserUrl != null) {
 			String parserFactoryClassName = null;
 			InputStream is = parserUrl.openStream();
 			BufferedReader br = new BufferedReader(new InputStreamReader(is));
 			while (true) {
 				parserFactoryClassName = br.readLine();
 				if (parserFactoryClassName == null) {
 					break; // end of file reached
 				}
 				String pfcName = parserFactoryClassName.trim();
 				if (pfcName.length() == 0) {
 					continue; // blank line
 				}
 				int commentIdx = pfcName.indexOf("#");
 				if (commentIdx == 0) { // comment line
 					continue;
 				}
 				else
 					if (commentIdx < 0) { // no comment on this line
 						v.addElement(pfcName);
 					}
 					else {
 						v.addElement(pfcName.substring(0, commentIdx).trim());
 					}
 			}
 			return v;
 		}
 		else {
 			return null;
 		}
 	}

 	/**
 	 * Register SAX Parser Factory Services with the framework.
 	 *
 	 * @param parserFactoryClassNames - a <code>Vector</code> of
 	 *        <code>String</code> objects containing the names of the parser
 	 *        Factory Classes
 	 * @throws FactoryConfigurationError if thrown from <code>getFactory</code>
 	 */
 	private void registerSAXParsers(Vector parserFactoryClassNames)
 			throws FactoryConfigurationError {
 		if (parserFactoryClassNames != null) {
 			Enumeration e = parserFactoryClassNames.elements();
 			int index = 0;
 			while (e.hasMoreElements()) {
 				String parserFactoryClassName = (String) e.nextElement();
 				// create a sax parser factory just to get it's default
 				// properties. It will never be used since
 				// this class will operate as a service factory and give each
 				// service requestor it's own SaxParserFactory
 				SAXParserFactory factory = (SAXParserFactory) getFactory(parserFactoryClassName);
 				Hashtable properties = new Hashtable(7);
 				// figure out the default properties of the parser
 				setDefaultSAXProperties(factory, properties, index);
 				// store the parser factory class name in the properties so that
 				// it can be retrieved when getService is called
 				// to return a parser factory
 				properties.put(FACTORYNAMEKEY, parserFactoryClassName);
 				// release the factory
 				factory = null;
 				// register the factory as a service
 				context.registerService(SAXFACTORYNAME, this, properties);
 				index++;
 			}
 		}
 	}

 	/**
 	 * <p>
 	 * Set the SAX Parser Service Properties. By default, the following
 	 * properties are set:
 	 * <ul>
 	 * <li><code>SERVICE_DESCRIPTION</code>
 	 * <li><code>SERVICE_PID</code>
 	 * <li><code>PARSER_VALIDATING</code>- instantiates a parser and queries
 	 * it to find out whether it is validating or not
 	 * <li><code>PARSER_NAMESPACEAWARE</code>- instantiates a parser and
 	 * queries it to find out whether it is namespace aware or not
 	 * <ul>
 	 *
 	 * @param factory The <code>SAXParserFactory</code> object
 	 * @param props <code>Hashtable</code> of service properties.
 	 */
 	private void setDefaultSAXProperties(SAXParserFactory factory,
 			Hashtable props, int index) {
 		props.put(Constants.SERVICE_DESCRIPTION, SAXFACTORYDESCRIPTION);
 		props.put(Constants.SERVICE_PID, SAXFACTORYNAME + "."
 				+ context.getBundle().getBundleId() + "." + index);
 		setSAXProperties(factory, props);
 	}

 	/**
 	 * <p>
 	 * Set the customizable SAX Parser Service Properties.
 	 *
 	 * <p>
 	 * This method attempts to instantiate a validating parser and a
 	 * namespaceaware parser to determine if the parser can support those
 	 * features. The appropriate properties are then set in the specified
 	 * properties object.
 	 *
 	 * <p>
 	 * This method can be overridden to add additional SAX2 features and
 	 * properties. If you want to be able to filter searches of the OSGi service
 	 * registry, this method must put a key, value pair into the properties
 	 * object for each feature or property. For example,
 	 *
 	 * properties.put("http://www.acme.com/features/foo", Boolean.TRUE);
 	 *
 	 * @param factory - the SAXParserFactory object
 	 * @param properties - the properties object for the service
 	 */
 	public void setSAXProperties(SAXParserFactory factory, Hashtable properties) {
 		SAXParser parser = null;
 		// check if this parser can be configured to validate
 		boolean validating = true;
 		factory.setValidating(true);
 		factory.setNamespaceAware(false);
 		try {
 			parser = factory.newSAXParser();
 		}
 		catch (Exception pce_val) {
 			validating = false;
 		}
 		// check if this parser can be configured to be namespaceaware
 		boolean namespaceaware = true;
 		factory.setValidating(false);
 		factory.setNamespaceAware(true);
 		try {
 			parser = factory.newSAXParser();
 		}
 		catch (Exception pce_nsa) {
 			namespaceaware = false;
 		}
 		// set the factory values
 		factory.setValidating(validating);
 		factory.setNamespaceAware(namespaceaware);
 		// set the OSGi service properties
 		properties.put(PARSER_NAMESPACEAWARE, new Boolean(namespaceaware));
 		properties.put(PARSER_VALIDATING, new Boolean(validating));
 	}

 	/**
 	 * Register DOM Parser Factory Services with the framework.
 	 *
 	 * @param parserFactoryClassNames - a <code>Vector</code> of
 	 *        <code>String</code> objects containing the names of the parser
 	 *        Factory Classes
 	 * @throws FactoryConfigurationError if thrown from <code>getFactory</code>
 	 */
 	private void registerDOMParsers(Vector parserFactoryClassNames)
 			throws FactoryConfigurationError {
 		if (parserFactoryClassNames != null) {
 			Enumeration e = parserFactoryClassNames.elements();
 			int index = 0;
 			while (e.hasMoreElements()) {
 				String parserFactoryClassName = (String) e.nextElement();
 				// create a dom parser factory just to get it's default
 				// properties. It will never be used since
 				// this class will operate as a service factory and give each
 				// service requestor it's own DocumentBuilderFactory
 				DocumentBuilderFactory factory = (DocumentBuilderFactory) getFactory(parserFactoryClassName);
 				Hashtable properties = new Hashtable(7);
 				// figure out the default properties of the parser
 				setDefaultDOMProperties(factory, properties, index);
 				// store the parser factory class name in the properties so that
 				// it can be retrieved when getService is called
 				// to return a parser factory
 				properties.put(FACTORYNAMEKEY, parserFactoryClassName);
 				// release the factory
 				factory = null;
 				// register the factory as a service
 				context.registerService(DOMFACTORYNAME, this, properties);
 				index++;
 			}
 		}
 	}

 	/**
 	 * Set the DOM parser service properties.
 	 *
 	 * By default, the following properties are set:
 	 * <ul>
 	 * <li><code>SERVICE_DESCRIPTION</code>
 	 * <li><code>SERVICE_PID</code>
 	 * <li><code>PARSER_VALIDATING</code>
 	 * <li><code>PARSER_NAMESPACEAWARE</code>
 	 * <ul>
 	 *
 	 * @param factory The <code>DocumentBuilderFactory</code> object
 	 * @param props <code>Hashtable</code> of service properties.
 	 */
 	private void setDefaultDOMProperties(DocumentBuilderFactory factory,
 			Hashtable props, int index) {
 		props.put(Constants.SERVICE_DESCRIPTION, DOMFACTORYDESCRIPTION);
 		props.put(Constants.SERVICE_PID, DOMFACTORYNAME + "."
 				+ context.getBundle().getBundleId() + "." + index);
 		setDOMProperties(factory, props);
 	}

 	/**
 	 * <p>
 	 * Set the customizable DOM Parser Service Properties.
 	 *
 	 * <p>
 	 * This method attempts to instantiate a validating parser and a
 	 * namespaceaware parser to determine if the parser can support those
 	 * features. The appropriate properties are then set in the specified props
 	 * object.
 	 *
 	 * <p>
 	 * This method can be overridden to add additional DOM2 features and
 	 * properties. If you want to be able to filter searches of the OSGi service
 	 * registry, this method must put a key, value pair into the properties
 	 * object for each feature or property. For example,
 	 *
 	 * properties.put("http://www.acme.com/features/foo", Boolean.TRUE);
 	 *
 	 * @param factory - the DocumentBuilderFactory object
 	 * @param props - Hashtable of service properties.
 	 */
 	public void setDOMProperties(DocumentBuilderFactory factory, Hashtable props) {
 		DocumentBuilder parser = null;
 		// check if this parser can be configured to validate
 		boolean validating = true;
 		factory.setValidating(true);
 		factory.setNamespaceAware(false);
 		try {
 			parser = factory.newDocumentBuilder();
 		}
 		catch (Exception pce_val) {
 			validating = false;
 		}
 		// check if this parser can be configured to be namespaceaware
 		boolean namespaceaware = true;
 		factory.setValidating(false);
 		factory.setNamespaceAware(true);
 		try {
 			parser = factory.newDocumentBuilder();
 		}
 		catch (Exception pce_nsa) {
 			namespaceaware = false;
 		}
 		// set the factory values
 		factory.setValidating(validating);
 		factory.setNamespaceAware(namespaceaware);
 		// set the OSGi service properties
 		props.put(PARSER_VALIDATING, new Boolean(validating));
 		props.put(PARSER_NAMESPACEAWARE, new Boolean(namespaceaware));
 	}

 	/**
 	 * Given a parser factory class name, instantiate that class.
 	 *
 	 * @param parserFactoryClassName A <code>String</code> object containing
 	 *        the name of the parser factory class
 	 * @return a parserFactoryClass Object
 	 * @pre parserFactoryClassName!=null
 	 */
 	private Object getFactory(String parserFactoryClassName)
 			throws FactoryConfigurationError {
 		Exception e = null;
 		try {
 			return Class.forName(parserFactoryClassName).newInstance();
 		}
 		catch (ClassNotFoundException cnfe) {
 			e = cnfe;
 		}
 		catch (InstantiationException ie) {
 			e = ie;
 		}
 		catch (IllegalAccessException iae) {
 			e = iae;
 		}
 		throw new FactoryConfigurationError(e);
 	}

 	/**
 	 * Creates a new XML Parser Factory object.
 	 *
 	 * <p>
 	 * A unique XML Parser Factory object is returned for each call to this
 	 * method.
 	 *
 	 * <p>
 	 * The returned XML Parser Factory object will be configured for validating
 	 * and namespace aware support as specified in the service properties of the
 	 * specified ServiceRegistration object.
 	 *
 	 * This method can be overridden to configure additional features in the
 	 * returned XML Parser Factory object.
 	 *
 	 * @param bundle The bundle using the service.
 	 * @param registration The <code>ServiceRegistration</code> object for the
 	 *        service.
 	 * @return A new, configured XML Parser Factory object or null if a
 	 *         configuration error was encountered
 	 */
 	public Object getService(Bundle bundle, ServiceRegistration registration) {
 		ServiceReference sref = registration.getReference();
 		String parserFactoryClassName = (String) sref
 				.getProperty(FACTORYNAMEKEY);
 		try {
 			// need to set factory properties
 			Object factory = getFactory(parserFactoryClassName);
 			if (factory instanceof SAXParserFactory) {
 				((SAXParserFactory) factory).setValidating(((Boolean) sref
 						.getProperty(PARSER_VALIDATING)).booleanValue());
 				((SAXParserFactory) factory).setNamespaceAware(((Boolean) sref
 						.getProperty(PARSER_NAMESPACEAWARE)).booleanValue());
 			}
 			else
 				if (factory instanceof DocumentBuilderFactory) {
 					((DocumentBuilderFactory) factory)
 							.setValidating(((Boolean) sref
 									.getProperty(PARSER_VALIDATING))
 									.booleanValue());
 					((DocumentBuilderFactory) factory)
 							.setNamespaceAware(((Boolean) sref
 									.getProperty(PARSER_NAMESPACEAWARE))
 									.booleanValue());
 				}
 			return factory;
 		}
 		catch (FactoryConfigurationError fce) {
 			fce.printStackTrace();
 			return null;
 		}
 	}

 	/**
 	 * Releases a XML Parser Factory object.
 	 *
 	 * @param bundle The bundle releasing the service.
 	 * @param registration The <code>ServiceRegistration</code> object for the
 	 *        service.
 	 * @param service The XML Parser Factory object returned by a previous call
 	 *        to the <code>getService</code> method.
 	 */
 	public void ungetService(Bundle bundle, ServiceRegistration registration,
 			Object service) {
 	}
 }
	/*
	* $Header: /cvshome/build/org.osgi.util.xml/src/org/osgi/util/xml/XMLParserActivator.java,v 1.8 2006/03/14 01:21:37 hargrave Exp $
	*
	* Copyright (c) OSGi Alliance (2002, 2005). All Rights Reserved.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package org.osgi.util.xml;

	import java.io.*;
	import java.net.URL;
	import java.util.*;

	import javax.xml.parsers.*;

	import org.osgi.framework.*;

	/**
	* A BundleActivator class that allows any JAXP compliant XML Parser to register
	* itself as an OSGi parser service.
	*
	* Multiple JAXP compliant parsers can concurrently register by using this
	* BundleActivator class. Bundles who wish to use an XML parser can then use the
	* framework's service registry to locate available XML Parsers with the desired
	* characteristics such as validating and namespace-aware.
	*
	* <p>
	* The services that this bundle activator enables a bundle to provide are:
	* <ul>
	* <li><code>javax.xml.parsers.SAXParserFactory</code>({@link #SAXFACTORYNAME})
	* <li><code>javax.xml.parsers.DocumentBuilderFactory</code>(
	* {@link #DOMFACTORYNAME})
	* </ul>
	*
	* <p>
	* The algorithm to find the implementations of the abstract parsers is derived
	* from the JAR file specifications, specifically the Services API.
	* <p>
	* An XMLParserActivator assumes that it can find the class file names of the
	* factory classes in the following files:
	* <ul>
	* <li><code>/META-INF/services/javax.xml.parsers.SAXParserFactory</code> is
	* a file contained in a jar available to the runtime which contains the
	* implementation class name(s) of the SAXParserFactory.
	* <li><code>/META-INF/services/javax.xml.parsers.DocumentBuilderFactory</code>
	* is a file contained in a jar available to the runtime which contains the
	* implementation class name(s) of the <code>DocumentBuilderFactory</code>
	* </ul>
	* <p>
	* If either of the files does not exist, <code>XMLParserActivator</code>
	* assumes that the parser does not support that parser type.
	*
	* <p>
	* <code>XMLParserActivator</code> attempts to instantiate both the
	* <code>SAXParserFactory</code> and the <code>DocumentBuilderFactory</code>.
	* It registers each factory with the framework along with service properties:
	* <ul>
	* <li>{@link #PARSER_VALIDATING}- indicates if this factory supports
	* validating parsers. It's value is a <code>Boolean</code>.
	* <li>{@link #PARSER_NAMESPACEAWARE}- indicates if this factory supports
	* namespace aware parsers It's value is a <code>Boolean</code>.
	* </ul>
	* <p>
	* Individual parser implementations may have additional features, properties,
	* or attributes which could be used to select a parser with a filter. These can
	* be added by extending this class and overriding the
	* <code>setSAXProperties</code> and <code>setDOMProperties</code> methods.
	*/
	public class XMLParserActivator implements BundleActivator, ServiceFactory {
	/** Context of this bundle */
	private BundleContext context;
	/**
	* Filename containing the SAX Parser Factory Class name. Also used as the
	* basis for the <code>SERVICE_PID<code> registration property.
	*/
	public static final String SAXFACTORYNAME = "javax.xml.parsers.SAXParserFactory";
	/**
	* Filename containing the DOM Parser Factory Class name. Also used as the
	* basis for the <code>SERVICE_PID</code> registration property.
	*/
	public static final String DOMFACTORYNAME = "javax.xml.parsers.DocumentBuilderFactory";
	/** Path to the factory class name files */
	private static final String PARSERCLASSFILEPATH = "/META-INF/services/";
	/** Fully qualified path name of SAX Parser Factory Class Name file */
	public static final String SAXCLASSFILE = PARSERCLASSFILEPATH
	+ SAXFACTORYNAME;
	/** Fully qualified path name of DOM Parser Factory Class Name file */
	public static final String DOMCLASSFILE = PARSERCLASSFILEPATH
	+ DOMFACTORYNAME;
	/** SAX Factory Service Description */
	private static final String SAXFACTORYDESCRIPTION = "A JAXP Compliant SAX Parser";
	/** DOM Factory Service Description */
	private static final String DOMFACTORYDESCRIPTION = "A JAXP Compliant DOM Parser";
	/**
	* Service property specifying if factory is configured to support
	* validating parsers. The value is of type <code>Boolean</code>.
	*/
	public static final String PARSER_VALIDATING = "parser.validating";
	/**
	* Service property specifying if factory is configured to support namespace
	* aware parsers. The value is of type <code>Boolean</code>.
	*/
	public static final String PARSER_NAMESPACEAWARE = "parser.namespaceAware";
	/**
	* Key for parser factory name property - this must be saved in the parsers
	* properties hashtable so that the parser factory can be instantiated from
	* a ServiceReference
	*/
	private static final String FACTORYNAMEKEY = "parser.factoryname";

	/**
	* Called when this bundle is started so the Framework can perform the
	* bundle-specific activities necessary to start this bundle. This method
	* can be used to register services or to allocate any resources that this
	* bundle needs.
	*
	* <p>
	* This method must complete and return to its caller in a timely manner.
	*
	* <p>
	* This method attempts to register a SAX and DOM parser with the
	* Framework's service registry.
	*
	* @param context The execution context of the bundle being started.
	* @throws java.lang.Exception If this method throws an exception, this
	* bundle is marked as stopped and the Framework will remove this
	* bundle's listeners, unregister all services registered by this
	* bundle, and release all services used by this bundle.
	* @see Bundle#start
	*/
	public void start(BundleContext context) throws Exception {
	this.context = context;
	Bundle parserBundle = context.getBundle();
	try {
	// check for sax parsers
	registerSAXParsers(getParserFactoryClassNames(parserBundle
	.getResource(SAXCLASSFILE)));
	// check for dom parsers
	registerDOMParsers(getParserFactoryClassNames(parserBundle
	.getResource(DOMCLASSFILE)));
	}
	catch (IOException ioe) {
	// if there were any IO errors accessing the resource files
	// containing the class names
	ioe.printStackTrace();
	throw new FactoryConfigurationError(ioe);
	}
	}

	/**
	* <p>
	* This method has nothing to do as all active service registrations will
	* automatically get unregistered when the bundle stops.
	*
	* @param context The execution context of the bundle being stopped.
	* @throws java.lang.Exception If this method throws an exception, the
	* bundle is still marked as stopped, and the Framework will remove
	* the bundle's listeners, unregister all services registered by the
	* bundle, and release all services used by the bundle.
	* @see Bundle#stop
	*/
	public void stop(BundleContext context) throws Exception {
	}

	/**
	* Given the URL for a file, reads and returns the parser class names. There
	* may be multiple classes specified in this file, one per line. There may
	* also be comment lines in the file, which begin with "#".
	*
	* @param parserUrl The URL of the service file containing the parser class
	* names
	* @return A vector of strings containing the parser class names or null if
	* parserUrl is null
	* @throws IOException if there is a problem reading the URL input stream
	*/
	private Vector getParserFactoryClassNames(URL parserUrl) throws IOException {
	Vector v = new Vector(1);
	if (parserUrl != null) {
	String parserFactoryClassName = null;
	InputStream is = parserUrl.openStream();
	BufferedReader br = new BufferedReader(new InputStreamReader(is));
	while (true) {
	parserFactoryClassName = br.readLine();
	if (parserFactoryClassName == null) {
	break; // end of file reached
	}
	String pfcName = parserFactoryClassName.trim();
	if (pfcName.length() == 0) {
	continue; // blank line
	}
	int commentIdx = pfcName.indexOf("#");
	if (commentIdx == 0) { // comment line
	continue;
	}
	else
	if (commentIdx < 0) { // no comment on this line
	v.addElement(pfcName);
	}
	else {
	v.addElement(pfcName.substring(0, commentIdx).trim());
	}
	}
	return v;
	}
	else {
	return null;
	}
	}

	/**
	* Register SAX Parser Factory Services with the framework.
	*
	* @param parserFactoryClassNames - a <code>Vector</code> of
	* <code>String</code> objects containing the names of the parser
	* Factory Classes
	* @throws FactoryConfigurationError if thrown from <code>getFactory</code>
	*/
	private void registerSAXParsers(Vector parserFactoryClassNames)
	throws FactoryConfigurationError {
	if (parserFactoryClassNames != null) {
	Enumeration e = parserFactoryClassNames.elements();
	int index = 0;
	while (e.hasMoreElements()) {
	String parserFactoryClassName = (String) e.nextElement();
	// create a sax parser factory just to get it's default
	// properties. It will never be used since
	// this class will operate as a service factory and give each
	// service requestor it's own SaxParserFactory
	SAXParserFactory factory = (SAXParserFactory) getFactory(parserFactoryClassName);
	Hashtable properties = new Hashtable(7);
	// figure out the default properties of the parser
	setDefaultSAXProperties(factory, properties, index);
	// store the parser factory class name in the properties so that
	// it can be retrieved when getService is called
	// to return a parser factory
	properties.put(FACTORYNAMEKEY, parserFactoryClassName);
	// release the factory
	factory = null;
	// register the factory as a service
	context.registerService(SAXFACTORYNAME, this, properties);
	index++;
	}
	}
	}

	/**
	* <p>
	* Set the SAX Parser Service Properties. By default, the following
	* properties are set:
	* <ul>
	* <li><code>SERVICE_DESCRIPTION</code>
	* <li><code>SERVICE_PID</code>
	* <li><code>PARSER_VALIDATING</code>- instantiates a parser and queries
	* it to find out whether it is validating or not
	* <li><code>PARSER_NAMESPACEAWARE</code>- instantiates a parser and
	* queries it to find out whether it is namespace aware or not
	* <ul>
	*
	* @param factory The <code>SAXParserFactory</code> object
	* @param props <code>Hashtable</code> of service properties.
	*/
	private void setDefaultSAXProperties(SAXParserFactory factory,
	Hashtable props, int index) {
	props.put(Constants.SERVICE_DESCRIPTION, SAXFACTORYDESCRIPTION);
	props.put(Constants.SERVICE_PID, SAXFACTORYNAME + "."
	+ context.getBundle().getBundleId() + "." + index);
	setSAXProperties(factory, props);
	}

	/**
	* <p>
	* Set the customizable SAX Parser Service Properties.
	*
	* <p>
	* This method attempts to instantiate a validating parser and a
	* namespaceaware parser to determine if the parser can support those
	* features. The appropriate properties are then set in the specified
	* properties object.
	*
	* <p>
	* This method can be overridden to add additional SAX2 features and
	* properties. If you want to be able to filter searches of the OSGi service
	* registry, this method must put a key, value pair into the properties
	* object for each feature or property. For example,
	*
	* properties.put("http://www.acme.com/features/foo", Boolean.TRUE);
	*
	* @param factory - the SAXParserFactory object
	* @param properties - the properties object for the service
	*/
	public void setSAXProperties(SAXParserFactory factory, Hashtable properties) {
	SAXParser parser = null;
	// check if this parser can be configured to validate
	boolean validating = true;
	factory.setValidating(true);
	factory.setNamespaceAware(false);
	try {
	parser = factory.newSAXParser();
	}
	catch (Exception pce_val) {
	validating = false;
	}
	// check if this parser can be configured to be namespaceaware
	boolean namespaceaware = true;
	factory.setValidating(false);
	factory.setNamespaceAware(true);
	try {
	parser = factory.newSAXParser();
	}
	catch (Exception pce_nsa) {
	namespaceaware = false;
	}
	// set the factory values
	factory.setValidating(validating);
	factory.setNamespaceAware(namespaceaware);
	// set the OSGi service properties
	properties.put(PARSER_NAMESPACEAWARE, new Boolean(namespaceaware));
	properties.put(PARSER_VALIDATING, new Boolean(validating));
	}

	/**
	* Register DOM Parser Factory Services with the framework.
	*
	* @param parserFactoryClassNames - a <code>Vector</code> of
	* <code>String</code> objects containing the names of the parser
	* Factory Classes
	* @throws FactoryConfigurationError if thrown from <code>getFactory</code>
	*/
	private void registerDOMParsers(Vector parserFactoryClassNames)
	throws FactoryConfigurationError {
	if (parserFactoryClassNames != null) {
	Enumeration e = parserFactoryClassNames.elements();
	int index = 0;
	while (e.hasMoreElements()) {
	String parserFactoryClassName = (String) e.nextElement();
	// create a dom parser factory just to get it's default
	// properties. It will never be used since
	// this class will operate as a service factory and give each
	// service requestor it's own DocumentBuilderFactory
	DocumentBuilderFactory factory = (DocumentBuilderFactory) getFactory(parserFactoryClassName);
	Hashtable properties = new Hashtable(7);
	// figure out the default properties of the parser
	setDefaultDOMProperties(factory, properties, index);
	// store the parser factory class name in the properties so that
	// it can be retrieved when getService is called
	// to return a parser factory
	properties.put(FACTORYNAMEKEY, parserFactoryClassName);
	// release the factory
	factory = null;
	// register the factory as a service
	context.registerService(DOMFACTORYNAME, this, properties);
	index++;
	}
	}
	}

	/**
	* Set the DOM parser service properties.
	*
	* By default, the following properties are set:
	* <ul>
	* <li><code>SERVICE_DESCRIPTION</code>
	* <li><code>SERVICE_PID</code>
	* <li><code>PARSER_VALIDATING</code>
	* <li><code>PARSER_NAMESPACEAWARE</code>
	* <ul>
	*
	* @param factory The <code>DocumentBuilderFactory</code> object
	* @param props <code>Hashtable</code> of service properties.
	*/
	private void setDefaultDOMProperties(DocumentBuilderFactory factory,
	Hashtable props, int index) {
	props.put(Constants.SERVICE_DESCRIPTION, DOMFACTORYDESCRIPTION);
	props.put(Constants.SERVICE_PID, DOMFACTORYNAME + "."
	+ context.getBundle().getBundleId() + "." + index);
	setDOMProperties(factory, props);
	}

	/**
	* <p>
	* Set the customizable DOM Parser Service Properties.
	*
	* <p>
	* This method attempts to instantiate a validating parser and a
	* namespaceaware parser to determine if the parser can support those
	* features. The appropriate properties are then set in the specified props
	* object.
	*
	* <p>
	* This method can be overridden to add additional DOM2 features and
	* properties. If you want to be able to filter searches of the OSGi service
	* registry, this method must put a key, value pair into the properties
	* object for each feature or property. For example,
	*
	* properties.put("http://www.acme.com/features/foo", Boolean.TRUE);
	*
	* @param factory - the DocumentBuilderFactory object
	* @param props - Hashtable of service properties.
	*/
	public void setDOMProperties(DocumentBuilderFactory factory, Hashtable props) {
	DocumentBuilder parser = null;
	// check if this parser can be configured to validate
	boolean validating = true;
	factory.setValidating(true);
	factory.setNamespaceAware(false);
	try {
	parser = factory.newDocumentBuilder();
	}
	catch (Exception pce_val) {
	validating = false;
	}
	// check if this parser can be configured to be namespaceaware
	boolean namespaceaware = true;
	factory.setValidating(false);
	factory.setNamespaceAware(true);
	try {
	parser = factory.newDocumentBuilder();
	}
	catch (Exception pce_nsa) {
	namespaceaware = false;
	}
	// set the factory values
	factory.setValidating(validating);
	factory.setNamespaceAware(namespaceaware);
	// set the OSGi service properties
	props.put(PARSER_VALIDATING, new Boolean(validating));
	props.put(PARSER_NAMESPACEAWARE, new Boolean(namespaceaware));
	}

	/**
	* Given a parser factory class name, instantiate that class.
	*
	* @param parserFactoryClassName A <code>String</code> object containing
	* the name of the parser factory class
	* @return a parserFactoryClass Object
	* @pre parserFactoryClassName!=null
	*/
	private Object getFactory(String parserFactoryClassName)
	throws FactoryConfigurationError {
	Exception e = null;
	try {
	return Class.forName(parserFactoryClassName).newInstance();
	}
	catch (ClassNotFoundException cnfe) {
	e = cnfe;
	}
	catch (InstantiationException ie) {
	e = ie;
	}
	catch (IllegalAccessException iae) {
	e = iae;
	}
	throw new FactoryConfigurationError(e);
	}

	/**
	* Creates a new XML Parser Factory object.
	*
	* <p>
	* A unique XML Parser Factory object is returned for each call to this
	* method.
	*
	* <p>
	* The returned XML Parser Factory object will be configured for validating
	* and namespace aware support as specified in the service properties of the
	* specified ServiceRegistration object.
	*
	* This method can be overridden to configure additional features in the
	* returned XML Parser Factory object.
	*
	* @param bundle The bundle using the service.
	* @param registration The <code>ServiceRegistration</code> object for the
	* service.
	* @return A new, configured XML Parser Factory object or null if a
	* configuration error was encountered
	*/
	public Object getService(Bundle bundle, ServiceRegistration registration) {
	ServiceReference sref = registration.getReference();
	String parserFactoryClassName = (String) sref
	.getProperty(FACTORYNAMEKEY);
	try {
	// need to set factory properties
	Object factory = getFactory(parserFactoryClassName);
	if (factory instanceof SAXParserFactory) {
	((SAXParserFactory) factory).setValidating(((Boolean) sref
	.getProperty(PARSER_VALIDATING)).booleanValue());
	((SAXParserFactory) factory).setNamespaceAware(((Boolean) sref
	.getProperty(PARSER_NAMESPACEAWARE)).booleanValue());
	}
	else
	if (factory instanceof DocumentBuilderFactory) {
	((DocumentBuilderFactory) factory)
	.setValidating(((Boolean) sref
	.getProperty(PARSER_VALIDATING))
	.booleanValue());
	((DocumentBuilderFactory) factory)
	.setNamespaceAware(((Boolean) sref
	.getProperty(PARSER_NAMESPACEAWARE))
	.booleanValue());
	}
	return factory;
	}
	catch (FactoryConfigurationError fce) {
	fce.printStackTrace();
	return null;
	}
	}

	/**
	* Releases a XML Parser Factory object.
	*
	* @param bundle The bundle releasing the service.
	* @param registration The <code>ServiceRegistration</code> object for the
	* service.
	* @param service The XML Parser Factory object returned by a previous call
	* to the <code>getService</code> method.
	*/
	public void ungetService(Bundle bundle, ServiceRegistration registration,
	Object service) {
	}
	}