class RubyXL::OOXMLTopLevelObject

their own .xml files in .xslx zip container.
Extension class providing functionality for top-level OOXML objects that are represented by

def self.filepath 

def self.filepath
  raise 'Subclass responsebility'
end

def self.parse_file(dirpath)

* +dirpath+ - path to the directory with the unzipped .xslx contents.
=== Parameters
directory containing the unzipped contents of .xslx
Generates the top-level OOXML object by parsing its XML file from the temporary 
def self.parse_file(dirpath)
  full_path = File.join(dirpath, filepath)
  return nil unless File.exist?(full_path)
  parse(File.open(full_path, 'r'))
end

def self.set_namespaces(namespace_hash)

'xmlns:r' => 'http://schemas.openxmlformats.org/officeDocument/2006/relationships')
set_namespaces('xmlns' => 'http://schemas.openxmlformats.org/spreadsheetml/2006/main',
==== Examples
* +namespace_hash+ - Hash of namespaces in the form of "prefix" => "url"
=== Parameters
Sets the list of namespaces on this object to be added when writing out XML. Valid only on top-level objects. 
def self.set_namespaces(namespace_hash)
  self.class_variable_set(:@@ooxml_namespaces, namespace_hash)
end

def add_to_zip(zipfile)

* +zipfile+ - ::Zip::File to which the resulting XNMML should be added.
=== Parameters
Saves the contents of the object as XML to respective location in .xslx zip container. 
def add_to_zip(zipfile)
  xml_string = write_xml
  return if xml_string.empty?
  zipfile.get_output_stream(self.filepath) { |f| f << xml_string }
end

def filepath

is located within the .xslx zip container.
Prototype method. For top-level OOXML object, returns the path at which the current object's XML file 
def filepath
  self.class.filepath
end