Class: ActiveRDF::Namespace

Inherits:
Object
  • Object
show all
Defined in:
lib/active_rdf/objectmanager/namespace.rb

Constant Summary collapse

@@namespaces = 
Hash.new
@@inverted_namespaces = 
Hash.new

Class Method Summary collapse

Class Method Details

.abbreviate(obj) ⇒ Object

abbreviates resource if namespace is registered, otherwise returns nil



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 90

def Namespace.abbreviate(obj)
  uri = obj.to_s
  # uri.to_s gives us the uri of the resource (if resource given)
  # then we find the last occurrence of # or / (heuristical namespace
  # delimitor)
  delimiter = uri.rindex(/#|\//)

  if delimiter.nil? or delimiter == uri.size-1
    abbr = @@inverted_namespaces[uri]
    abbr.to_s if (abbr)
  else
    abbr = @@inverted_namespaces[uri[0..delimiter]]
    abbr.to_s.upcase + "::" + uri[delimiter+1..-1] if (abbr)
  end
end

.abbreviations ⇒ Object

returns currently registered namespace abbreviations (e.g. :foaf, :rdf)



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 35

def Namespace.abbreviations
  @@namespaces.keys
end

.expand(prefix, localname) ⇒ Object

returns URI (string) formed by concatenation of prefix and localname



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 55

def Namespace.expand(prefix, localname)
  prefix = prefix.downcase if prefix.is_a?String
  prefix = prefix.to_sym
  @@namespaces[prefix].to_s + localname.to_s if @@namespaces[prefix]
end

.find(name) ⇒ Object

like include?, but returns the key for the namespace



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 44

def Namespace.find(name)
  name = name.to_s.downcase.to_sym
  @@namespaces.keys.find{|k| k == name}
end

.include?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_rdf/objectmanager/namespace.rb', line 39

def Namespace.include?(name)
  @@namespaces.keys.include?(name.to_s.downcase.to_sym)
end

.localname(obj) ⇒ Object

returns local-part of URI



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 79

def Namespace.localname(obj)
  uri = obj.respond_to?(:uri) ? obj.uri : obj.to_s
  delimiter = uri.rindex(/#|\//)
  if delimiter.nil? or delimiter == uri.size-1
    uri
  else
    uri[delimiter+1..-1]
  end
end

.lookup(prefix, localname) ⇒ Object

returns a resource whose URI is formed by concatenation of prefix and localname



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 50

def Namespace.lookup(prefix, localname)
  RDFS::Resource.new(expand(prefix, localname))
end

.prefix(obj) ⇒ Object

returns prefix (if known) for the non-local part of the URI, or nil if prefix not registered



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 63

def Namespace.prefix(obj)
  uri = obj.respond_to?(:uri) ? obj.uri : obj.to_s
  # uri.to_s gives us the uri of the resource (if resource given)
  # then we find the last occurrence of # or / (heuristical namespace
  # delimitor)
  delimiter = uri.rindex(/#|\//)

  # if delimiter not found, URI cannot be split into (non)local-part
  return uri if delimiter.nil?

  # extract non-local part (including delimiter)
  nonlocal = uri[0..delimiter]
  @@inverted_namespaces[nonlocal]
end

.register(prefix, fullURI) ⇒ Object

registers a namespace prefix and its associated expansion (full URI) e.g. :rdf and ‘www.w3.org/1999/02/22-rdf-syntax-ns#’

Raises:



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# File 'lib/active_rdf/objectmanager/namespace.rb', line 11

def Namespace.register(prefix, fullURI)
  raise ActiveRdfError, 'prefix nor uri can be empty' if (prefix.to_s.empty? or fullURI.to_s.empty?)
  raise ActiveRdfError, "namespace uri should end with # or /" unless /\/|#/ =~ fullURI.to_s[-1..-1]
  klass_name = prefix.to_s.upcase
  prefix = prefix.to_s.downcase.to_sym
ActiveRdfLogger::log_info(self) {  "Namespace: registering #{fullURI} to #{klass_name}" }
  @@namespaces[prefix] = fullURI.to_s
  @@inverted_namespaces[fullURI.to_s] = prefix

  # enable namespace lookups through FOAF::name
  # if FOAF defined, extend it
  if Object.const_defined?(klass_name)
    ns = Object.const_get(klass_name)
  else
    # otherwise create a new module for it
    ns = Module.new
    Object.const_set(klass_name, ns)
  end
  ns.extend NamespaceProxy
  ns.prefix = prefix
  ns
end