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Class: REXML::Attribute

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, Namespace, XMLTokens, Node
Inherits: Object
Defined in: lib/rexml/attribute.rb

Overview

Defines an Element Attribute; IE, a attribute=value pair, as in: <element attribute=“value”/>. Attributes can be in their own namespaces. General users of ::REXML will not interact with the Attribute class much.

Constant Summary

XMLTokens - Included

NAME, NAMECHAR, NAME_CHAR, NAME_START_CHAR, NAME_STR, NCNAME_STR, NMTOKEN, NMTOKENS, REFERENCE

Namespace - Included

NAMESPLIT

Class Method Summary

Instance Attribute Summary

Namespace - Included

#expanded_name

The name of the object, valid if set.
#local_name

Alias for Namespace#name.
#name

The name of the object, valid if set.
#name=

Sets the name and the expanded name.
#prefix

The expanded name of the object, valid if name is set.

Node - Included

#parent?

Instance Method Summary

Namespace - Included

#fully_expanded_name

Fully expand the name, even if the prefix wasn’t specified in the source file.
#has_name?

Compares names optionally WITH namespaces.

Node - Included

#each_recursive

Visit all subnodes of self recursively.
#find_first_recursive

Find (and return) first subnode (recursively) for which the block evaluates to true.
#indent,
#index_in_parent

Returns the position that self holds in its parent’s array, indexed from 1.
#next_sibling_node, #previous_sibling_node,
#to_s
indent

Constructor Details

.new(first, second = nil, parent = nil) ⇒ Attribute

Constructor. FIXME: The parser doesn’t catch illegal characters in attributes

first

Either: an Attribute, which this new attribute will become a clone of; or a String, which is the name of this attribute

second

If first is an Attribute, then this may be an Element, or nil. If nil, then the Element parent of this attribute is the parent of the first Attribute. If the first argument is a String, then this must also be a String, and is the content of the attribute. If this is the content, it must be fully normalized (contain no illegal characters).

parent

Ignored unless first is a String; otherwise, may be the Element parent of this attribute, or nil.

Attribute.new( attribute_to_clone )
Attribute.new( attribute_to_clone, parent_element )
Attribute.new( "attr", "attr_value" )
Attribute.new( "attr", "attr_value", parent_element )
[ GitHub ] 

  


# File 'lib/rexml/attribute.rb', line 45



def initialize( first, second=nil, parent=nil )
  @normalized = @unnormalized = @element = nil
  if first.kind_of? Attribute
    self.name = first.expanded_name
    @unnormalized = first.value
    if second.kind_of? Element
      @element = second
    else
      @element = first.element
    end
  elsif first.kind_of? String
    @element = parent
    self.name = first
    @normalized = second.to_s
  else
    raise "illegal argument #{first.class.name} to Attribute constructor"
  end
end


  







Instance Attribute Details



  

    #element   (rw)
  



  

    

The element to which this attribute belongs


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 15



attr_reader :element


  








  

    #element=(element)   (rw)
  



  

    

Sets the element of which this object is an attribute.  Normally, this is not directly called.



Returns this attribute


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 166



def element=( element )
  @element = element

  if @normalized
    Text.check( @normalized, NEEDS_A_SECOND_CHECK, doctype )
  end

  self
end


  








  

    #normalized=(value)   (writeonly)
  



  

    

The normalized value of this attribute.  That is, the attribute with entities intact.


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 18



attr_writer :normalized


  







Instance Method Details



  

    #==(other)  
  



  

    

Returns true if other is an Attribute and has the same name and value, false otherwise.


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 109



def ==( other )
  other.kind_of?(Attribute) and other.name==name and other.value==value
end


  








  

    #clone  
  



  

    

Returns a copy of this attribute


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 158



def clone
  Attribute.new self
end


  








  

    #doctype  
  

  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 132



def doctype
  if @element
    doc = @element.document
    doc.doctype if doc
  end
end


  








  

    #hash  
  



  

    

Creates (and returns) a hash from both the name and value


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 114



def hash
  name.hash + value.hash
end


  








  

    #inspect  
  

  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 192



def inspect
  rv = ""
  write( rv )
  rv
end


  








  

    #namespace(arg = nil)  
  



  

    

Returns the namespace URL, if defined, or nil otherwise



e = Element.new("el")
e.add_namespace("ns", "http://url")
e.add_attribute("ns:a", "b")
e.add_attribute("nsx:a", "c")
e.attribute("ns:a").namespace # => "http://url"
e.attribute("nsx:a").namespace # => nil



This method always returns “” for no namespace attribute. Because the default namespace doesn’t apply to attribute names.



From www.w3.org/TR/xml-names/#uniqAttrs



> the default namespace does not apply to attribute names



e = REXML::Element.new("el")
e.add_namespace("", "http://example.com/")
e.namespace # => "http://example.com/"
e.add_attribute("a", "b")
e.attribute("a").namespace # => ""


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 98



def namespace arg=nil
  arg = prefix if arg.nil?
  if arg == ""
    ""
  else
    @element.namespace(arg)
  end
end


  








  

    #node_type  
  

  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 188



def node_type
  :attribute
end


  








  

    #prefix  
  



  

    

Returns the namespace of the attribute.



e = Element.new( "elns:myelement" )
e.add_attribute( "nsa:a", "aval" )
e.add_attribute( "b", "bval" )
e.attributes.get_attribute( "a" ).prefix   # -> "nsa"
e.attributes.get_attribute( "b" ).prefix   # -> ""
a = Attribute.new( "x", "y" )
a.prefix                                   # -> ""


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 73



def prefix
  super
end


  








  

    #remove  
  



  

    

Removes this Attribute from the tree, and returns true if successful



This method is usually not called directly.


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 179



def remove
  @element.attributes.delete self.name unless @element.nil?
end


  








  

    #to_s  
  



  

    

Returns the attribute value, with entities replaced


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 140



def to_s
  return @normalized if @normalized

  @normalized = Text::normalize( @unnormalized, doctype )
  @unnormalized = nil
  @normalized
end


  








  

    #to_string  
  



  

    

Returns this attribute out as XML source, expanding the name



a = Attribute.new( "x", "y" )
a.to_string     # -> "x='y'"
b = Attribute.new( "ns:x", "y" )
b.to_string     # -> "ns:x='y'"


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 124



def to_string
  if @element and @element.context and @element.context[:attribute_quote] == :quote
    %Q^#@expanded_name="#{to_s().gsub(/"/, '&quot;')}"^
  else
    "#@expanded_name='#{to_s().gsub(/'/, '&apos;')}'"
  end
end


  








  

    #value  
  



  

    

Returns the UNNORMALIZED value of this attribute.  That is, entities have been expanded to their values


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 150



def value
  return @unnormalized if @unnormalized
  @unnormalized = Text::unnormalize( @normalized, doctype )
  @normalized = nil
  @unnormalized
end


  








  

    #write(output, indent = -1 ))  
  



  

    

Writes this attribute (EG, puts ‘key=“value”’ to the output)


  



  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 184



def write( output, indent=-1 )
  output << to_string
end


  








  

    #xpath  
  

  [ GitHub ]


  

  


# File 'lib/rexml/attribute.rb', line 198



def xpath
  path = @element.xpath
  path += "/@#{self.expanded_name}"
  return path
end