Class: REXML::Attributes
Overview
A class that defines the set of Attributes of an Element and provides operations for accessing elements in that set.
Instance Method Summary collapse
-
#[](name) ⇒ Object
Fetches an attribute value.
-
#[]=(name, value) ⇒ Object
Sets an attribute, overwriting any existing attribute value by the same name.
-
#add(attribute) ⇒ Object
(also: #<<)
Adds an attribute, overriding any existing attribute by the same name.
-
#delete(attribute) ⇒ Object
- Removes an attribute attribute
-
either a String, which is the name of the attribute to remove – namespaces are significant here – or the attribute to remove.
-
#delete_all(name) ⇒ Object
Deletes all attributes matching a name.
-
#each ⇒ Object
Iterates over each attribute of an Element, yielding the expanded name and value as a pair of Strings.
-
#each_attribute ⇒ Object
Iterates over the attributes of an Element.
-
#get_attribute(name) ⇒ Object
- Fetches an attribute name
-
the name by which to search for the attribute.
-
#get_attribute_ns(namespace, name) ⇒ Object
The
get_attribute_ns
method retrieves a method by its namespace and name. -
#initialize(element) ⇒ Attributes
constructor
- Constructor element
-
the Element of which this is an Attribute.
-
#length ⇒ Object
(also: #size)
Returns the number of attributes the owning Element contains.
- #namespaces ⇒ Object
-
#prefixes ⇒ Object
Returns an array of Strings containing all of the prefixes declared by this set of # attributes.
- #to_a ⇒ Object
Constructor Details
#initialize(element) ⇒ Attributes
Constructor
- element
-
the Element of which this is an Attribute
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# File 'lib/rexml/element.rb', line 968 def initialize element @element = element end |
Instance Method Details
#[](name) ⇒ Object
Fetches an attribute value. If you want to get the Attribute itself, use get_attribute()
- name
-
an XPath attribute name. Namespaces are relevant here.
- Returns
-
the String value of the matching attribute, or
nil
if no matching attribute was found. This is the unnormalized value (with entities expanded).
doc = Document.new "<a foo:att='1' bar:att='2' att='<'/>"
doc.root.attributes['att'] #-> '<'
doc.root.attributes['bar:att'] #-> '2'
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# File 'lib/rexml/element.rb', line 983 def [](name) attr = get_attribute(name) return attr.value unless attr.nil? return nil end |
#[]=(name, value) ⇒ Object
Sets an attribute, overwriting any existing attribute value by the same name. Namespace is significant.
- name
-
the name of the attribute
- value
-
(optional) If supplied, the value of the attribute. If nil, any existing matching attribute is deleted.
- Returns
-
Owning element
doc = Document.new "<a x:foo='1' foo='3'/>"
doc.root.attributes['y:foo'] = '2'
doc.root.attributes['foo'] = '4'
doc.root.attributes['x:foo'] = nil
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# File 'lib/rexml/element.rb', line 1085 def []=( name, value ) if value.nil? # Delete the named attribute attr = get_attribute(name) delete attr return end unless value.kind_of? Attribute if @element.document and @element.document.doctype value = Text::normalize( value, @element.document.doctype ) else value = Text::normalize( value, nil ) end value = Attribute.new(name, value) end value.element = @element old_attr = fetch(value.name, nil) if old_attr.nil? store(value.name, value) elsif old_attr.kind_of? Hash old_attr[value.prefix] = value elsif old_attr.prefix != value.prefix # Check for conflicting namespaces raise ParseException.new( "Namespace conflict in adding attribute \"#{value.name}\": "+ "Prefix \"#{old_attr.prefix}\" = "+ "\"#{@element.namespace(old_attr.prefix)}\" and prefix "+ "\"#{value.prefix}\" = \"#{@element.namespace(value.prefix)}\"") if value.prefix != "xmlns" and old_attr.prefix != "xmlns" and @element.namespace( old_attr.prefix ) == @element.namespace( value.prefix ) store value.name, { old_attr.prefix => old_attr, value.prefix => value } else store value.name, value end return @element end |
#add(attribute) ⇒ Object Also known as: <<
Adds an attribute, overriding any existing attribute by the same name. Namespaces are significant.
- attribute
-
An Attribute
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# File 'lib/rexml/element.rb', line 1202 def add( attribute ) self[attribute.name] = attribute end |
#delete(attribute) ⇒ Object
Removes an attribute
- attribute
-
either a String, which is the name of the attribute to remove – namespaces are significant here – or the attribute to remove.
- Returns
-
the owning element
doc = Document.new "<a y:foo='0' x:foo='1' foo='3' z:foo='4'/>"
doc.root.attributes.delete 'foo' #-> <a y:foo='0' x:foo='1' z:foo='4'/>"
doc.root.attributes.delete 'x:foo' #-> <a y:foo='0' z:foo='4'/>"
attr = doc.root.attributes.get_attribute('y:foo')
doc.root.attributes.delete attr #-> <a z:foo='4'/>"
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# File 'lib/rexml/element.rb', line 1172 def delete( attribute ) name = nil prefix = nil if attribute.kind_of? Attribute name = attribute.name prefix = attribute.prefix else attribute =~ Namespace::NAMESPLIT prefix, name = $1, $2 prefix = '' unless prefix end old = fetch(name, nil) if old.kind_of? Hash # the supplied attribute is one of many old.delete(prefix) if old.size == 1 repl = nil old.each_value{|v| repl = v} store name, repl end elsif old.nil? return @element else # the supplied attribute is a top-level one super(name) end @element end |
#delete_all(name) ⇒ Object
Deletes all attributes matching a name. Namespaces are significant.
- name
-
A String; all attributes that match this path will be removed
- Returns
-
an Array of the Attributes that were removed
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# File 'lib/rexml/element.rb', line 1212 def delete_all( name ) rv = [] each_attribute { |attribute| rv << attribute if attribute. == name } rv.each{ |attr| attr.remove } return rv end |
#each ⇒ Object
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# File 'lib/rexml/element.rb', line 1025 def each each_attribute do |attr| yield [attr., attr.value] end end |
#each_attribute ⇒ Object
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# File 'lib/rexml/element.rb', line 1010 def each_attribute # :yields: attribute each_value do |val| if val.kind_of? Attribute yield val else val.each_value { |atr| yield atr } end end end |
#get_attribute(name) ⇒ Object
Fetches an attribute
- name
-
the name by which to search for the attribute. Can be a
prefix:name
namespace name. - Returns
-
The first matching attribute, or nil if there was none. This
value is an Attribute node, not the String value of the attribute.
doc = Document.new '<a x:foo="1" foo="2" bar="3"/>'
doc.root.attributes.get_attribute("foo").value #-> "2"
doc.root.attributes.get_attribute("x:foo").value #-> "1"
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# File 'lib/rexml/element.rb', line 1040 def get_attribute( name ) attr = fetch( name, nil ) if attr.nil? return nil if name.nil? # Look for prefix name =~ Namespace::NAMESPLIT prefix, n = $1, $2 if prefix attr = fetch( n, nil ) # check prefix if attr == nil elsif attr.kind_of? Attribute return attr if prefix == attr.prefix else attr = attr[ prefix ] return attr end end element_document = @element.document if element_document and element_document.doctype expn = @element. expn = element_document.doctype.name if expn.size == 0 attr_val = element_document.doctype.attribute_of(expn, name) return Attribute.new( name, attr_val ) if attr_val end return nil end if attr.kind_of? Hash attr = attr[ @element.prefix ] end return attr end |
#get_attribute_ns(namespace, name) ⇒ Object
The get_attribute_ns
method retrieves a method by its namespace and name. Thus it is possible to reliably identify an attribute even if an XML processor has changed the prefix.
Method contributed by Henrik Martensson
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# File 'lib/rexml/element.rb', line 1226 def get_attribute_ns(namespace, name) result = nil each_attribute() { |attribute| if name == attribute.name && namespace == attribute.namespace() && ( !namespace.empty? || !attribute..index(':') ) # foo will match xmlns:foo, but only if foo isn't also an attribute result = attribute if !result or !namespace.empty? or !attribute..index(':') end } result end |
#length ⇒ Object Also known as: size
Returns the number of attributes the owning Element contains.
doc = Document "<a x='1' y='2' foo:x='3'/>"
doc.root.attributes.length #-> 3
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# File 'lib/rexml/element.rb', line 996 def length c = 0 each_attribute { c+=1 } c end |
#namespaces ⇒ Object
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# File 'lib/rexml/element.rb', line 1146 def namespaces namespaces = {} each_attribute do |attribute| namespaces[attribute.name] = attribute.value if attribute.prefix == 'xmlns' or attribute.name == 'xmlns' end if @element.document and @element.document.doctype expn = @element. expn = @element.document.doctype.name if expn.size == 0 @element.document.doctype.attributes_of(expn).each { |attribute| namespaces[attribute.name] = attribute.value if attribute.prefix == 'xmlns' or attribute.name == 'xmlns' } end namespaces end |
#prefixes ⇒ Object
Returns an array of Strings containing all of the prefixes declared by this set of # attributes. The array does not include the default namespace declaration, if one exists.
doc = Document.new("<a xmlns='foo' xmlns:x='bar' xmlns:y='twee' "+
"z='glorp' p:k='gru'/>")
prefixes = doc.root.attributes.prefixes #-> ['x', 'y']
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# File 'lib/rexml/element.rb', line 1130 def prefixes ns = [] each_attribute do |attribute| ns << attribute.name if attribute.prefix == 'xmlns' end if @element.document and @element.document.doctype expn = @element. expn = @element.document.doctype.name if expn.size == 0 @element.document.doctype.attributes_of(expn).each { |attribute| ns << attribute.name if attribute.prefix == 'xmlns' } end ns end |
#to_a ⇒ Object
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# File 'lib/rexml/element.rb', line 989 def to_a enum_for(:each_attribute).to_a end |