Parent
Represents a tagged XML element. Elements
are characterized by having children, attributes, and names, and can themselves be children.
Constructor
if not supplied, will be set to the default value. If a String, the name of this object will be set to the argument. If an Element
, the object will be shallowly cloned; name, attributes, and namespaces will be copied. Children will not
be copied.
if supplied, must be a Parent
, and will be used as the parent of this object.
If supplied, must be a hash containing context items. Context items include:
:respect_whitespace
the value of this is :all
or an array of strings being the names of the elements to respect whitespace for. Defaults to :all
.
:compress_whitespace
the value can be :all
or an array of strings being the names of the elements to ignore whitespace on. Overrides :respect_whitespace
.
:ignore_whitespace_nodes
the value can be :all
or an array of strings being the names of the elements in which to ignore whitespace-only nodes. If this is set, Text
nodes which contain only whitespace will not be added to the document tree.
:raw
can be :all
, or an array of strings being the names of the elements to process in raw mode. In raw mode, special characters in text is not converted to or from entities.
# File rexml/element.rb, line 59 def initialize( arg = UNDEFINED, parent=nil, context=nil ) super(parent) @elements = Elements.new(self) @attributes = Attributes.new(self) @context = context if arg.kind_of? String self.name = arg elsif arg.kind_of? Element self.name = arg.expanded_name arg.attributes.each_attribute{ |attribute| @attributes << Attribute.new( attribute ) } @context = arg.context end end
Fetches an attribute value or a child.
If String or Symbol
is specified, it's treated as attribute name. Attribute
value as String or nil
is returned. This case is shortcut of +attributes+.
If Integer
is specified, it's treated as the index of child. It returns Nth child.
doc = REXML::Document.new("<a attr='1'><b/><c/></a>") doc.root["attr"] # => "1" doc.root.attributes["attr"] # => "1" doc.root[1] # => <c/>
# File rexml/element.rb, line 567 def [](name_or_index) case name_or_index when String attributes[name_or_index] when Symbol attributes[name_or_index.to_s] else super end end
Adds an attribute to this element, overwriting any existing attribute by the same name.
can be either an Attribute
or a String. If an Attribute
, the attribute is added to the list of Element
attributes. If String, the argument is used as the name of the new attribute, and the value parameter must be supplied.
Required if key
is a String, and ignored if the first argument is an Attribute
. This is a String, and is used as the value of the new Attribute
. This should be the unnormalized value of the attribute (without entities).
the Attribute
added
e = Element.new 'e' e.add_attribute( 'a', 'b' ) #-> <e a='b'/> e.add_attribute( 'x:a', 'c' ) #-> <e a='b' x:a='c'/> e.add_attribute Attribute.new('b', 'd') #-> <e a='b' x:a='c' b='d'/>
# File rexml/element.rb, line 624 def add_attribute( key, value=nil ) if key.kind_of? Attribute @attributes << key else @attributes[key] = value end end
Add multiple attributes to this element.
is either a hash, or array of arrays
el.add_attributes( {"name1"=>"value1", "name2"=>"value2"} ) el.add_attributes( [ ["name1","value1"], ["name2"=>"value2"] ] )
# File rexml/element.rb, line 636 def add_attributes hash if hash.kind_of? Hash hash.each_pair {|key, value| @attributes[key] = value } elsif hash.kind_of? Array hash.each { |value| @attributes[ value[0] ] = value[1] } end end
Adds a child to this element, optionally setting attributes in the element.
optional. If Element
, the element is added. Otherwise, a new Element
is constructed with the argument (see Element.initialize).
If supplied, must be a Hash containing String name,value pairs, which will be used to set the attributes of the new Element
.
the Element
that was added
el = doc.add_element 'my-tag' el = doc.add_element 'my-tag', {'attr1'=>'val1', 'attr2'=>'val2'} el = Element.new 'my-tag' doc.add_element el
# File rexml/element.rb, line 296 def add_element element, attrs=nil raise "First argument must be either an element name, or an Element object" if element.nil? el = @elements.add(element) attrs.each do |key, value| el.attributes[key]=value end if attrs.kind_of? Hash el end
Adds a namespace to this element.
the prefix string, or the namespace URI if uri
is not supplied
the namespace URI. May be nil, in which prefix
is used as the URI
Evaluates to: this Element
a = Element.new("a") a.add_namespace("xmlns:foo", "bar" ) a.add_namespace("foo", "bar") # shorthand for previous line a.add_namespace("twiddle") puts a #-> <a xmlns:foo='bar' xmlns='twiddle'/>
# File rexml/element.rb, line 251 def add_namespace( prefix, uri=nil ) unless uri @attributes["xmlns"] = prefix else prefix = "xmlns:#{prefix}" unless prefix =~ /^xmlns:/ @attributes[ prefix ] = uri end self end
A helper method to add a Text
child. Actual Text
instances can be added with regular Parent
methods, such as add() and <<()
if a String, a new Text
instance is created and added to the parent. If Text
, the object is added directly.
this Element
e = Element.new('a') #-> <e/> e.add_text 'foo' #-> <e>foo</e> e.add_text Text.new(' bar') #-> <e>foo bar</e>
Note that at the end of this example, the branch has 3 nodes; the 'e' element and 2 Text
node children.
# File rexml/element.rb, line 523 def add_text( text ) if text.kind_of? String if @children[-1].kind_of? Text @children[-1] << text return end text = Text.new( text, whitespace(), nil, raw() ) end self << text unless text.nil? return self end
# File rexml/element.rb, line 578 def attribute( name, namespace=nil ) prefix = nil if namespaces.respond_to? :key prefix = namespaces.key(namespace) if namespace else prefix = namespaces.index(namespace) if namespace end prefix = nil if prefix == 'xmlns' ret_val = attributes.get_attribute( "#{prefix ? prefix + ':' : ''}#{name}" ) return ret_val unless ret_val.nil? return nil if prefix.nil? # now check that prefix'es namespace is not the same as the # default namespace return nil unless ( namespaces[ prefix ] == namespaces[ 'xmlns' ] ) attributes.get_attribute( name ) end
Get an array of all CData
children. IMMUTABLE
# File rexml/element.rb, line 668 def cdatas find_all { |child| child.kind_of? CData }.freeze end
Creates a shallow copy of self.
d = Document.new "<a><b/><b/><c><d/></c></a>" new_a = d.root.clone puts new_a # => "<a/>"
# File rexml/element.rb, line 97 def clone self.class.new self end
Removes an attribute
either an Attribute
or a String. In either case, the attribute is found by matching the attribute name to the argument, and then removed. If no attribute is found, no action is taken.
the attribute removed, or nil if this Element
did not contain a matching attribute
e = Element.new('E') e.add_attribute( 'name', 'Sean' ) #-> <E name='Sean'/> r = e.add_attribute( 'sur:name', 'Russell' ) #-> <E name='Sean' sur:name='Russell'/> e.delete_attribute( 'name' ) #-> <E sur:name='Russell'/> e.delete_attribute( r ) #-> <E/>
# File rexml/element.rb, line 657 def delete_attribute(key) attr = @attributes.get_attribute(key) attr.remove unless attr.nil? end
Deletes a child element.
Must be an Element
, String
, or Integer
. If Element
, the element is removed. If String, the element is found (via XPath
) and removed. <em>This means that any parent can remove any descendant.<em> If Integer
, the Element
indexed by that number will be removed.
the element that was removed.
doc.delete_element "/a/b/c[@id='4']" doc.delete_element doc.elements["//k"] doc.delete_element 1
# File rexml/element.rb, line 316 def delete_element element @elements.delete element end
Removes a namespace from this node. This only works if the namespace is actually declared in this node. If no argument is passed, deletes the default namespace.
Evaluates to: this element
doc = Document.new "<a xmlns:foo='bar' xmlns='twiddle'/>" doc.root.delete_namespace puts doc # -> <a xmlns:foo='bar'/> doc.root.delete_namespace 'foo' puts doc # -> <a/>
# File rexml/element.rb, line 271 def delete_namespace namespace="xmlns" namespace = "xmlns:#{namespace}" unless namespace == 'xmlns' attribute = attributes.get_attribute(namespace) attribute.remove unless attribute.nil? self end
Evaluates to the document to which this element belongs, or nil if this element doesn't belong to a document.
# File rexml/element.rb, line 132 def document rt = root rt.parent if rt end
Synonym for Element.elements
.each
# File rexml/element.rb, line 393 def each_element( xpath=nil, &block ) # :yields: Element @elements.each( xpath, &block ) end
Iterates through the child elements, yielding for each Element
that has a particular attribute set.
the name of the attribute to search for
the value of the attribute
(optional) causes this method to return after yielding for this number of matching children
(optional) if supplied, this is an XPath
that filters the children to check.
doc = Document.new "<a><b @id='1'/><c @id='2'/><d @id='1'/><e/></a>" # Yields b, c, d doc.root.each_element_with_attribute( 'id' ) {|e| p e} # Yields b, d doc.root.each_element_with_attribute( 'id', '1' ) {|e| p e} # Yields b doc.root.each_element_with_attribute( 'id', '1', 1 ) {|e| p e} # Yields d doc.root.each_element_with_attribute( 'id', '1', 0, 'd' ) {|e| p e}
# File rexml/element.rb, line 351 def each_element_with_attribute( key, value=nil, max=0, name=nil, &block ) # :yields: Element each_with_something( proc {|child| if value.nil? child.attributes[key] != nil else child.attributes[key]==value end }, max, name, &block ) end
Iterates through the children, yielding for each Element
that has a particular text set.
the text to search for. If nil, or not supplied, will iterate over all Element
children that contain at least one Text
node.
(optional) causes this method to return after yielding for this number of matching children
(optional) if supplied, this is an XPath
that filters the children to check.
doc = Document.new '<a><b>b</b><c>b</c><d>d</d><e/></a>' # Yields b, c, d doc.each_element_with_text {|e|p e} # Yields b, c doc.each_element_with_text('b'){|e|p e} # Yields b doc.each_element_with_text('b', 1){|e|p e} # Yields d doc.each_element_with_text(nil, 0, 'd'){|e|p e}
# File rexml/element.rb, line 382 def each_element_with_text( text=nil, max=0, name=nil, &block ) # :yields: Element each_with_something( proc {|child| if text.nil? child.has_text? else child.text == text end }, max, name, &block ) end
Returns the first child Text
node, if any, or nil
otherwise. This method returns the actual Text
node, rather than the String content.
doc = Document.new "<p>some text <b>this is bold!</b> more text</p>" # The element 'p' has two text elements, "some text " and " more text". doc.root.get_text.value #-> "some text "
# File rexml/element.rb, line 462 def get_text path = nil rv = nil if path element = @elements[ path ] rv = element.get_text unless element.nil? else rv = @children.find { |node| node.kind_of? Text } end return rv end
Evaluates to true
if this element has any attributes set, false otherwise.
# File rexml/element.rb, line 603 def has_attributes? return !@attributes.empty? end
Evaluates to true
if this element has at least one child Element
doc = Document.new "<a><b/><c>Text</c></a>" doc.root.has_elements # -> true doc.elements["/a/b"].has_elements # -> false doc.elements["/a/c"].has_elements # -> false
# File rexml/element.rb, line 325 def has_elements? !@elements.empty? end
Evaluates to true
if this element has at least one Text
child
# File rexml/element.rb, line 433 def has_text? not text().nil? end
# File rexml/element.rb, line 162 def ignore_whitespace_nodes @ignore_whitespace_nodes = false if @context if @context[:ignore_whitespace_nodes] @ignore_whitespace_nodes = (@context[:ignore_whitespace_nodes] == :all or @context[:ignore_whitespace_nodes].include? expanded_name) end end end
# File rexml/element.rb, line 77 def inspect rv = "<#@expanded_name" @attributes.each_attribute do |attr| rv << " " attr.write( rv, 0 ) end if children.size > 0 rv << "> ... </>" else rv << "/>" end end
Get an array of all Instruction
children. IMMUTABLE
# File rexml/element.rb, line 680 def instructions find_all { |child| child.kind_of? Instruction }.freeze end
Evaluates to the URI for a prefix, or the empty string if no such namespace is declared for this element. Evaluates recursively for ancestors. Returns the default namespace, if there is one.
the prefix to search for. If not supplied, returns the default namespace if one exists
the namespace URI as a String, or nil if no such namespace exists. If the namespace is undefined, returns an empty string
doc = Document.new("<a xmlns='1' xmlns:y='2'><b/><c xmlns:z='3'/></a>") b = doc.elements['//b'] b.namespace # -> '1' b.namespace("y") # -> '2'
# File rexml/element.rb, line 223 def namespace(prefix=nil) if prefix.nil? prefix = prefix() end if prefix == '' prefix = "xmlns" else prefix = "xmlns:#{prefix}" unless prefix[0,5] == 'xmlns' end ns = attributes[ prefix ] ns = parent.namespace(prefix) if ns.nil? and parent ns = '' if ns.nil? and prefix == 'xmlns' return ns end
# File rexml/element.rb, line 203 def namespaces namespaces = {} namespaces = parent.namespaces if parent namespaces = namespaces.merge( attributes.namespaces ) return namespaces end
Returns the next sibling that is an element, or nil if there is no Element
sibling after this one
doc = Document.new '<a><b/>text<c/></a>' doc.root.elements['b'].next_element #-> <c/> doc.root.elements['c'].next_element #-> nil
# File rexml/element.rb, line 410 def next_element element = next_sibling element = element.next_sibling until element.nil? or element.kind_of? Element return element end
Evaluates to an Array
containing the prefixes (names) of all defined namespaces at this context node.
doc = Document.new("<a xmlns:x='1' xmlns:y='2'><b/><c xmlns:z='3'/></a>") doc.elements['//b'].prefixes # -> ['x', 'y']
# File rexml/element.rb, line 196 def prefixes prefixes = [] prefixes = parent.prefixes if parent prefixes |= attributes.prefixes return prefixes end
Returns the previous sibling that is an element, or nil if there is no Element
sibling prior to this one
doc = Document.new '<a><b/>text<c/></a>' doc.root.elements['c'].previous_element #-> <b/> doc.root.elements['b'].previous_element #-> nil
# File rexml/element.rb, line 421 def previous_element element = previous_sibling element = element.previous_sibling until element.nil? or element.kind_of? Element return element end
Evaluates to true
if raw mode is set for this element. This is the case if the context has :raw
set to :all
or an array containing the name of this element.
The evaluation is tested against expanded_name
, and so is namespace sensitive.
# File rexml/element.rb, line 179 def raw @raw = (@context and @context[:raw] and (@context[:raw] == :all or @context[:raw].include? expanded_name)) @raw end
# File rexml/element.rb, line 124 def root return elements[1] if self.kind_of? Document return self if parent.kind_of? Document or parent.nil? return parent.root end
Evaluates to the root node of the document that this element belongs to. If this element doesn't belong to a document, but does belong to another Element
, the parent's root will be returned, until the earliest ancestor is found.
Note that this is not the same as the document element. In the following example, <a> is the document element, and the root node is the parent node of the document element. You may ask yourself why the root node is useful: consider the doctype and XML declaration, and any processing instructions before the document element… they are children of the root node, or siblings of the document element. The only time this isn't true is when an Element
is created that is not part of any Document
. In this case, the ancestor that has no parent acts as the root node.
d = Document.new '<a><b><c/></b></a>' a = d[1] ; c = a[1][1] d.root_node == d # TRUE a.root_node # namely, d c.root_node # again, d
# File rexml/element.rb, line 120 def root_node parent.nil? ? self : parent.root_node end
A convenience method which returns the String value of the first child text element, if one exists, and nil
otherwise.
Note that an element may have multiple Text
elements, perhaps separated by other children. Be aware that this method only returns the first Text
node.
This method returns the value
of the first text child node, which ignores the raw
setting, so always returns normalized text. See the Text::value documentation.
doc = Document.new "<p>some text <b>this is bold!</b> more text</p>" # The element 'p' has two text elements, "some text " and " more text". doc.root.text #-> "some text "
# File rexml/element.rb, line 451 def text( path = nil ) rv = get_text(path) return rv.value unless rv.nil? nil end
Sets the first Text
child of this object. See text() for a discussion about Text
children.
If a Text
child already exists, the child is replaced by this content. This means that Text
content can be deleted by calling this method with a nil argument. In this case, the next Text
child becomes the first Text
child. In no case is the order of any siblings disturbed.
If a String, a new Text
child is created and added to this Element
as the first Text
child. If Text
, the text is set as the first Child
element. If nil, then any existing first Text
child is removed.
this Element
.
doc = Document.new '<a><b/></a>' doc.root.text = 'Sean' #-> '<a><b/>Sean</a>' doc.root.text = 'Elliott' #-> '<a><b/>Elliott</a>' doc.root.add_element 'c' #-> '<a><b/>Elliott<c/></a>' doc.root.text = 'Russell' #-> '<a><b/>Russell<c/></a>' doc.root.text = nil #-> '<a><b/><c/></a>'
# File rexml/element.rb, line 493 def text=( text ) if text.kind_of? String text = Text.new( text, whitespace(), nil, raw() ) elsif !text.nil? and !text.kind_of? Text text = Text.new( text.to_s, whitespace(), nil, raw() ) end old_text = get_text if text.nil? old_text.remove unless old_text.nil? else if old_text.nil? self << text else old_text.replace_with( text ) end end return self end
Get an array of all Text
children. IMMUTABLE
# File rexml/element.rb, line 686 def texts find_all { |child| child.kind_of? Text }.freeze end
Evaluates to true
if whitespace is respected for this element. This is the case if:
Neither :respect_whitespace
nor :compress_whitespace
has any value
The context has :respect_whitespace
set to :all
or an array containing the name of this element, and :compress_whitespace
isn't set to :all
or an array containing the name of this element.
The evaluation is tested against expanded_name
, and so is namespace sensitive.
# File rexml/element.rb, line 146 def whitespace @whitespace = nil if @context if @context[:respect_whitespace] @whitespace = (@context[:respect_whitespace] == :all or @context[:respect_whitespace].include? expanded_name) end @whitespace = false if (@context[:compress_whitespace] and (@context[:compress_whitespace] == :all or @context[:compress_whitespace].include? expanded_name) ) end @whitespace = true unless @whitespace == false @whitespace end
Writes out this element, and recursively, all children.
output an object which supports '<< string'; this is where the
document will be written.
An integer. If -1, no indenting will be used; otherwise, the indentation will be this number of spaces, and children will be indented an additional amount. Defaults to -1
If transitive is true and indent is >= 0, then the output will be pretty-printed in such a way that the added whitespace does not affect the parse tree of the document
This hack inserts a space before the /> on empty tags to address a limitation of Internet Explorer. Defaults to false
out = '' doc.write( out ) #-> doc is written to the string 'out' doc.write( $stdout ) #-> doc written to the console
# File rexml/element.rb, line 712 def write(output=$stdout, indent=-1, transitive=false, ie_hack=false) Kernel.warn("#{self.class.name}.write is deprecated. See REXML::Formatters", uplevel: 1) formatter = if indent > -1 if transitive require "rexml/formatters/transitive" REXML::Formatters::Transitive.new( indent, ie_hack ) else REXML::Formatters::Pretty.new( indent, ie_hack ) end else REXML::Formatters::Default.new( ie_hack ) end formatter.write( self, output ) end
Get an array of all
Comment
children. IMMUTABLE