Parent
Represents a tagged XML element. Elements are characterized by having children, attributes, and names, and can themselves be children.
Constructor
arg |
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. |
parent |
if supplied, must be a Parent, and will be used as the parent of this object. |
context |
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 58
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
Adds an attribute to this element, overwriting any existing attribute by the same name.
key |
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. |
value |
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). |
Returns |
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 599
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.
hash |
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 611
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.
element |
optional. If Element, the element is added. Otherwise, a new Element is constructed with the argument (see Element.initialize). |
attrs |
If supplied, must be a Hash containing String name,value pairs, which will be used to set the attributes of the new Element. |
Returns |
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 295
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.
prefix |
the prefix string, or the namespace URI if uri is not supplied |
uri |
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 250
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 <<()
text |
if a String, a new Text instance is created and added to the parent. If Text, the object is added directly. |
Returns |
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 522
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 553
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 643
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 96
def clone
self.class.new self
end
Removes an attribute
key |
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. |
Returns |
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 632
def delete_attribute(key)
attr = @attributes.get_attribute(key)
attr.remove unless attr.nil?
end
Deletes a child element.
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. |
Returns |
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 315
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 270
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 131
def document
rt = root
rt.parent if rt
end
Synonym for Element.elements.each
# File rexml/element.rb, line 392
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.
key |
the name of the attribute to search for |
value |
the value of the attribute |
max |
(optional) causes this method to return after yielding for this number of matching children |
name |
(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 350
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.
text |
the text to search for. If nil, or not supplied, will iterate over all Element children that contain at least one Text node. |
max |
(optional) causes this method to return after yielding for this number of matching children |
name |
(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 381
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 461
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 578
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 324
def has_elements?
!@elements.empty?
end
Evaluates to true if this element has at least one Text child
# File rexml/element.rb, line 432
def has_text?
not text().nil?
end
# File rexml/element.rb, line 161
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 76
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 655
def instructions
find_all { |child| child.kind_of? Instruction }.freeze
end
Evalutas 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.
prefix |
the prefix to search for. If not supplied, returns the default namespace if one exists |
Returns |
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 222
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 202
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 409
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 195
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 420
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 178
def raw
@raw = (@context and @context[:raw] and
(@context[:raw] == :all or
@context[:raw].include? expanded_name))
@raw
end
# File rexml/element.rb, line 123
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 119
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 450
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.
text |
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. |
Returns |
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 492
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 661
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 145
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 |
output an object which supports ‘<< string’; this is where the |
document will be written.
indent |
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 |
transitive |
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 |
ie_hack |
Internet Explorer is the worst piece of crap to have ever been written, with the possible exception of Windows itself. Since IE is unable to parse proper XML, we have to provide a hack to generate XML that IE’s limited abilities can handle. This hack inserts a space before the /> on empty tags. Defaults to false |
out = '' doc.write( out ) #-> doc is written to the string 'out' doc.write( $stdout ) #-> doc written to the console
# File rexml/element.rb, line 690
def write(output=$stdout, indent=-1, transitive=false, ie_hack=false)
Kernel.warn("#{self.class.name}.write is deprecated. See REXML::Formatters")
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