Class: REXML::Attribute

Inherits:
Object show all
Includes:
Namespace, Node
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 collapse

PATTERN = 
/\s*(#{NAME_STR})\s*=\s*(["'])(.*?)\2/um
NEEDS_A_SECOND_CHECK = 
/(<|&((#{Entity::NAME});|(#0*((?:\d+)|(?:x[a-fA-F0-9]+)));)?)/um

Constants included from Namespace

Namespace::NAMESPLIT

Constants included from XMLTokens

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

Instance Attribute Summary collapse

Attributes included from Namespace

#expanded_name, #name

Instance Method Summary collapse

Methods included from Namespace

#fully_expanded_name, #has_name?

Methods included from Node

#each_recursive, #find_first_recursive, #indent, #index_in_parent, #next_sibling_node, #parent?, #previous_sibling_node

Constructor Details

#initialize(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 )



45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
 
# 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 ⇒ Object

The element to which this attribute belongs



15
16
17
 
# File 'lib/rexml/attribute.rb', line 15

def element
  @element
end

#normalized=(value) ⇒ Object (writeonly)

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



18
19
20
 
# File 'lib/rexml/attribute.rb', line 18

def normalized=(value)
  @normalized = value
end

Instance Method Details

#==(other) ⇒ Object

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



96
97
98
 
# File 'lib/rexml/attribute.rb', line 96

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

#clone ⇒ Object

Returns a copy of this attribute



145
146
147
 
# File 'lib/rexml/attribute.rb', line 145

def clone
  Attribute.new self
end

#doctype ⇒ Object 



119
120
121
122
123
124
 
# File 'lib/rexml/attribute.rb', line 119

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

#hash ⇒ Object

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



101
102
103
 
# File 'lib/rexml/attribute.rb', line 101

def hash
  name.hash + value.hash
end

#inspect ⇒ Object 



179
180
181
182
183
 
# File 'lib/rexml/attribute.rb', line 179

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

#namespace(arg = nil) ⇒ Object

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



89
90
91
92
 
# File 'lib/rexml/attribute.rb', line 89

def namespace arg=nil
  arg = prefix if arg.nil?
  @element.namespace arg
end

#node_type ⇒ Object 



175
176
177
 
# File 'lib/rexml/attribute.rb', line 175

def node_type
  :attribute
end

#prefix ⇒ Object

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   # -> "elns"
a = Attribute.new( "x", "y" )
a.prefix                                   # -> ""



73
74
75
76
77
78
79
 
# File 'lib/rexml/attribute.rb', line 73

def prefix
  pf = super
  if pf == ""
    pf = @element.prefix if @element
  end
  pf
end

#remove ⇒ Object

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

This method is usually not called directly.



166
167
168
 
# File 'lib/rexml/attribute.rb', line 166

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

#to_s ⇒ Object

Returns the attribute value, with entities replaced



127
128
129
130
131
132
133
 
# File 'lib/rexml/attribute.rb', line 127

def to_s
  return @normalized if @normalized

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

#to_string ⇒ Object

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'"



111
112
113
114
115
116
117
 
# File 'lib/rexml/attribute.rb', line 111

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 ⇒ Object

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



137
138
139
140
141
142
 
# File 'lib/rexml/attribute.rb', line 137

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

#write(output, indent = -1 )) ⇒ Object

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



171
172
173
 
# File 'lib/rexml/attribute.rb', line 171

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

#xpath ⇒ Object 



185
186
187
188
189
 
# File 'lib/rexml/attribute.rb', line 185

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