Package org.osgi.util.xml

Class XMLParserActivator

  • All Implemented Interfaces:
    org.osgi.framework.BundleActivator, org.osgi.framework.ServiceFactory<java.lang.Object>
    public class XMLParserActivator
extends java.lang.Object
implements org.osgi.framework.BundleActivator, org.osgi.framework.ServiceFactory<java.lang.Object>
    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.

    The services that this bundle activator enables a bundle to provide are:

    The algorithm to find the implementations of the abstract parsers is derived from the JAR file specifications, specifically the Services API.

    An XMLParserActivator assumes that it can find the class file names of the factory classes in the following files:

    • /META-INF/services/javax.xml.parsers.SAXParserFactory is a file contained in a jar available to the runtime which contains the implementation class name(s) of the SAXParserFactory.
    • /META-INF/services/javax.xml.parsers.DocumentBuilderFactory is a file contained in a jar available to the runtime which contains the implementation class name(s) of the DocumentBuilderFactory

    If either of the files does not exist, XMLParserActivator assumes that the parser does not support that parser type.

    XMLParserActivator attempts to instantiate both the SAXParserFactory and the DocumentBuilderFactory. It registers each factory with the framework along with service properties:

    • PARSER_VALIDATING- indicates if this factory supports validating parsers. It's value is a Boolean.
    • PARSER_NAMESPACEAWARE- indicates if this factory supports namespace aware parsers It's value is a Boolean.

    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 setSAXProperties and setDOMProperties methods.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String DOMCLASSFILE
      Fully qualified path name of DOM Parser Factory Class Name file
      static java.lang.String DOMFACTORYNAME
      Filename containing the DOM Parser Factory Class name.
      static java.lang.String PARSER_NAMESPACEAWARE
      Service property specifying if factory is configured to support namespace aware parsers.
      static java.lang.String PARSER_VALIDATING
      Service property specifying if factory is configured to support validating parsers.
      static java.lang.String SAXCLASSFILE
      Fully qualified path name of SAX Parser Factory Class Name file
      static java.lang.String SAXFACTORYNAME
      Filename containing the SAX Parser Factory Class name.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.Object getService​(org.osgi.framework.Bundle bundle, org.osgi.framework.ServiceRegistration<java.lang.Object> registration)
      Creates a new XML Parser Factory object.
      void setDOMProperties​(javax.xml.parsers.DocumentBuilderFactory factory, java.util.Hashtable<java.lang.String,​java.lang.Object> props)
      Set the customizable DOM Parser Service Properties.
      void setSAXProperties​(javax.xml.parsers.SAXParserFactory factory, java.util.Hashtable<java.lang.String,​java.lang.Object> properties)
      Set the customizable SAX Parser Service Properties.
      void start​(org.osgi.framework.BundleContext context)
      Called when this bundle is started so the Framework can perform the bundle-specific activities necessary to start this bundle.
      void stop​(org.osgi.framework.BundleContext context)
      This method has nothing to do as all active service registrations will automatically get unregistered when the bundle stops.
      void ungetService​(org.osgi.framework.Bundle bundle, org.osgi.framework.ServiceRegistration<java.lang.Object> registration, java.lang.Object service)
      Releases a XML Parser Factory object.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • SAXFACTORYNAME

        public static final java.lang.String SAXFACTORYNAME
        Filename containing the SAX Parser Factory Class name. Also used as the basis for the SERVICE_PID registration property.
        See Also:
        Constant Field Values

      • DOMFACTORYNAME

        public static final java.lang.String DOMFACTORYNAME
        Filename containing the DOM Parser Factory Class name. Also used as the basis for the SERVICE_PID registration property.
        See Also:
        Constant Field Values

      • SAXCLASSFILE

        public static final java.lang.String SAXCLASSFILE
        Fully qualified path name of SAX Parser Factory Class Name file
        See Also:
        Constant Field Values

      • DOMCLASSFILE

        public static final java.lang.String DOMCLASSFILE
        Fully qualified path name of DOM Parser Factory Class Name file
        See Also:
        Constant Field Values

      • PARSER_VALIDATING

        public static final java.lang.String PARSER_VALIDATING
        Service property specifying if factory is configured to support validating parsers. The value is of type Boolean.
        See Also:
        Constant Field Values

      • PARSER_NAMESPACEAWARE

        public static final java.lang.String PARSER_NAMESPACEAWARE
        Service property specifying if factory is configured to support namespace aware parsers. The value is of type Boolean.
        See Also:
        Constant Field Values

    • Constructor Detail

      • XMLParserActivator

        public XMLParserActivator()

    • Method Detail

      • start

        public void start​(org.osgi.framework.BundleContext context)
           throws java.lang.Exception
        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.

        This method must complete and return to its caller in a timely manner.

        This method attempts to register a SAX and DOM parser with the Framework's service registry.

        Specified by:
        start in interface org.osgi.framework.BundleActivator
        Parameters:
        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.

      • stop

        public void stop​(org.osgi.framework.BundleContext context)
          throws java.lang.Exception
        This method has nothing to do as all active service registrations will automatically get unregistered when the bundle stops.
        Specified by:
        stop in interface org.osgi.framework.BundleActivator
        Parameters:
        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.

      • setSAXProperties

        public void setSAXProperties​(javax.xml.parsers.SAXParserFactory factory,
                             java.util.Hashtable<java.lang.String,​java.lang.Object> properties)

        Set the customizable SAX Parser Service Properties.

        This method attempts to instantiate a validating parser and a namespace aware parser to determine if the parser can support those features. The appropriate properties are then set in the specified properties object.

        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);

        Parameters:
        factory - - the SAXParserFactory object
        properties - - the properties object for the service

      • setDOMProperties

        public void setDOMProperties​(javax.xml.parsers.DocumentBuilderFactory factory,
                             java.util.Hashtable<java.lang.String,​java.lang.Object> props)

        Set the customizable DOM Parser Service Properties.

        This method attempts to instantiate a validating parser and a namespace aware parser to determine if the parser can support those features. The appropriate properties are then set in the specified props object.

        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);

        Parameters:
        factory - - the DocumentBuilderFactory object
        props - - Hashtable of service properties.

      • getService

        public java.lang.Object getService​(org.osgi.framework.Bundle bundle,
                                   org.osgi.framework.ServiceRegistration<java.lang.Object> registration)
        Creates a new XML Parser Factory object.

        A unique XML Parser Factory object is returned for each call to this method.

        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.

        Specified by:
        getService in interface org.osgi.framework.ServiceFactory<java.lang.Object>
        Parameters:
        bundle - The bundle using the service.
        registration - The ServiceRegistration object for the service.
        Returns:
        A new, configured XML Parser Factory object or null if a configuration error was encountered

      • ungetService

        public void ungetService​(org.osgi.framework.Bundle bundle,
                         org.osgi.framework.ServiceRegistration<java.lang.Object> registration,
                         java.lang.Object service)
        Releases a XML Parser Factory object.
        Specified by:
        ungetService in interface org.osgi.framework.ServiceFactory<java.lang.Object>
        Parameters:
        bundle - The bundle releasing the service.
        registration - The ServiceRegistration object for the service.
        service - The XML Parser Factory object returned by a previous call to the getService method.