public static synchronized DataUsageExtension instance ( ) { if ( SINGLETON == null ) { SINGLETON = new DataUsageExtension ( ) ; XFactory factory = XFactoryRegistry . instance ( ) . currentDefault ( ) ; ATTR_DATA = factory . createAttributeLiteral ( KEY_DATA , "" , SINGLETON ) ; SINGLETON . eventAttributes . add ( ( XAttribute ) ATTR_DATA . clone ( ) ) ; // register mapping aliases for ( Map . Entry < String , String > mapping : EXTENSION_DESCRIPTIONS . entrySet ( ) ) { XGlobalAttributeNameMap . instance ( ) . registerMapping ( mapping . getKey ( ) , KEY_DATA , mapping . getValue ( ) ) ; } } return SINGLETON ; }
Provides access to the singleton instance of this extension .