Class XMLParserActivator
- java.lang.Object
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- org.osgi.util.xml.XMLParserActivator
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- 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:
javax.xml.parsers.SAXParserFactory
(SAXFACTORYNAME
)javax.xml.parsers.DocumentBuilderFactory
(DOMFACTORYNAME
)
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 theDocumentBuilderFactory
If either of the files does not exist,
XMLParserActivator
assumes that the parser does not support that parser type.XMLParserActivator
attempts to instantiate both theSAXParserFactory
and theDocumentBuilderFactory
. It registers each factory with the framework along with service properties:PARSER_VALIDATING
- indicates if this factory supports validating parsers. It's value is aBoolean
.PARSER_NAMESPACEAWARE
- indicates if this factory supports namespace aware parsers It's value is aBoolean
.
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
andsetDOMProperties
methods.
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Field Summary
Fields Modifier and Type Field Description private org.osgi.framework.BundleContext
bundleContext
Context of this bundlestatic java.lang.String
DOMCLASSFILE
Fully qualified path name of DOM Parser Factory Class Name fileprivate static java.lang.String
DOMFACTORYDESCRIPTION
DOM Factory Service Descriptionstatic java.lang.String
DOMFACTORYNAME
Filename containing the DOM Parser Factory Class name.private static java.lang.String
FACTORYNAMEKEY
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 ServiceReferencestatic 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.private static java.lang.String
PARSERCLASSFILEPATH
Path to the factory class name filesstatic java.lang.String
SAXCLASSFILE
Fully qualified path name of SAX Parser Factory Class Name fileprivate static java.lang.String
SAXFACTORYDESCRIPTION
SAX Factory Service Descriptionstatic java.lang.String
SAXFACTORYNAME
Filename containing the SAX Parser Factory Class name.
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Constructor Summary
Constructors Constructor Description XMLParserActivator()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description private java.lang.Object
getFactory(java.lang.String parserFactoryClassName)
Given a parser factory class name, instantiate that class.private java.util.List<java.lang.String>
getParserFactoryClassNames(java.net.URL parserUrl)
Given the URL for a file, reads and returns the parser class names.java.lang.Object
getService(org.osgi.framework.Bundle bundle, org.osgi.framework.ServiceRegistration<java.lang.Object> registration)
Creates a new XML Parser Factory object.private void
registerDOMParsers(java.util.List<java.lang.String> parserFactoryClassNames)
Register DOM Parser Factory Services with the framework.private void
registerSAXParsers(java.util.List<java.lang.String> parserFactoryClassNames)
Register SAX Parser Factory Services with the framework.private void
setDefaultDOMProperties(javax.xml.parsers.DocumentBuilderFactory factory, java.util.Hashtable<java.lang.String,java.lang.Object> props, int index)
Set the DOM parser service properties.private void
setDefaultSAXProperties(javax.xml.parsers.SAXParserFactory factory, java.util.Hashtable<java.lang.String,java.lang.Object> props, int index)
Set the SAX Parser Service Properties.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.
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Field Detail
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bundleContext
private volatile org.osgi.framework.BundleContext bundleContext
Context of this bundle
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SAXFACTORYNAME
public static final java.lang.String SAXFACTORYNAME
Filename containing the SAX Parser Factory Class name. Also used as the basis for theSERVICE_PID
registration property.- See Also:
- Constant Field Values
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DOMFACTORYNAME
public static final java.lang.String DOMFACTORYNAME
Filename containing the DOM Parser Factory Class name. Also used as the basis for theSERVICE_PID
registration property.- See Also:
- Constant Field Values
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PARSERCLASSFILEPATH
private static final java.lang.String PARSERCLASSFILEPATH
Path to the factory class name files- See Also:
- Constant Field Values
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SAXCLASSFILE
public static final java.lang.String SAXCLASSFILE
Fully qualified path name of SAX Parser Factory Class Name file- See Also:
- Constant Field Values
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DOMCLASSFILE
public static final java.lang.String DOMCLASSFILE
Fully qualified path name of DOM Parser Factory Class Name file- See Also:
- Constant Field Values
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SAXFACTORYDESCRIPTION
private static final java.lang.String SAXFACTORYDESCRIPTION
SAX Factory Service Description- See Also:
- Constant Field Values
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DOMFACTORYDESCRIPTION
private static final java.lang.String DOMFACTORYDESCRIPTION
DOM Factory Service Description- See Also:
- Constant Field Values
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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 typeBoolean
.- See Also:
- Constant Field Values
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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 typeBoolean
.- See Also:
- Constant Field Values
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FACTORYNAMEKEY
private static final java.lang.String FACTORYNAMEKEY
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- See Also:
- Constant Field Values
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Method Detail
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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 interfaceorg.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.
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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 interfaceorg.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.
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getParserFactoryClassNames
private java.util.List<java.lang.String> getParserFactoryClassNames(java.net.URL parserUrl) throws java.io.IOException
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 "#".- Parameters:
parserUrl
- The URL of the service file containing the parser class names- Returns:
- A List of strings containing the parser class names.
- Throws:
java.io.IOException
- if there is a problem reading the URL input stream
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registerSAXParsers
private void registerSAXParsers(java.util.List<java.lang.String> parserFactoryClassNames) throws javax.xml.parsers.FactoryConfigurationError
Register SAX Parser Factory Services with the framework.- Parameters:
parserFactoryClassNames
- - aList
ofString
objects containing the names of the parser Factory Classes- Throws:
javax.xml.parsers.FactoryConfigurationError
- if thrown fromgetFactory
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setDefaultSAXProperties
private void setDefaultSAXProperties(javax.xml.parsers.SAXParserFactory factory, java.util.Hashtable<java.lang.String,java.lang.Object> props, int index)
Set the SAX Parser Service Properties. By default, the following properties are set:
SERVICE_DESCRIPTION
SERVICE_PID
PARSER_VALIDATING
- instantiates a parser and queries it to find out whether it is validating or notPARSER_NAMESPACEAWARE
- instantiates a parser and queries it to find out whether it is namespace aware or not
- Parameters:
factory
- TheSAXParserFactory
objectprops
-Hashtable
of service properties.
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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 objectproperties
- - the properties object for the service
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registerDOMParsers
private void registerDOMParsers(java.util.List<java.lang.String> parserFactoryClassNames) throws javax.xml.parsers.FactoryConfigurationError
Register DOM Parser Factory Services with the framework.- Parameters:
parserFactoryClassNames
- - aList
ofString
objects containing the names of the parser Factory Classes- Throws:
javax.xml.parsers.FactoryConfigurationError
- if thrown fromgetFactory
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setDefaultDOMProperties
private void setDefaultDOMProperties(javax.xml.parsers.DocumentBuilderFactory factory, java.util.Hashtable<java.lang.String,java.lang.Object> props, int index)
Set the DOM parser service properties. By default, the following properties are set:SERVICE_DESCRIPTION
SERVICE_PID
PARSER_VALIDATING
PARSER_NAMESPACEAWARE
- Parameters:
factory
- TheDocumentBuilderFactory
objectprops
-Hashtable
of service properties.
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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 objectprops
- - Hashtable of service properties.
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getFactory
private java.lang.Object getFactory(java.lang.String parserFactoryClassName) throws javax.xml.parsers.FactoryConfigurationError
Given a parser factory class name, instantiate that class.- Parameters:
parserFactoryClassName
- AString
object containing the name of the parser factory class- Returns:
- a parserFactoryClass Object
- Throws:
javax.xml.parsers.FactoryConfigurationError
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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 interfaceorg.osgi.framework.ServiceFactory<java.lang.Object>
- Parameters:
bundle
- The bundle using the service.registration
- TheServiceRegistration
object for the service.- Returns:
- A new, configured XML Parser Factory object or null if a configuration error was encountered
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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 interfaceorg.osgi.framework.ServiceFactory<java.lang.Object>
- Parameters:
bundle
- The bundle releasing the service.registration
- TheServiceRegistration
object for the service.service
- The XML Parser Factory object returned by a previous call to thegetService
method.
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