question: public void close ( ) throws GraphIOException { try { document . clear ( ) ; if ( xmlEventReader != null ) { xmlEventReader . close ( ) ; } if ( fileReader != null ) { fileReader . close ( ) ; } if ( inputStream != null ) { inputStream . close ( ) ; } } catch ( IOException e ) { throw new GraphIOException ( e ) ; } catch ( XMLStreamException e ) { throw new GraphIOException ( e ) ; } finally { fileReader = null ; inputStream = null ; xmlEventReader = null ; graphTransformer = null ; vertexTransformer = null ; edgeTransformer = null ; hyperEdgeTransformer = null ; } }
target:  Closes the GraphML reader and disposes of any resources.