| In: |
rexml/element.rb
|
| Parent: | Parent |
Represents a tagged XML element. Elements are characterized by having children, attributes, and names, and can themselves be children.
| UNDEFINED | = | "UNDEFINED"; |
| attributes | [R] | Mechanisms for accessing attributes and child elements of this element. |
| context | [RW] | The context holds information about the processing environment, such as whitespace handling. |
| elements | [R] | Mechanisms for accessing attributes and child elements of this element. |
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. If a Source, the source will be scanned and parsed for an Element, and all child elements will be recursively parsed as well. |
| 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: |
# File rexml/element.rb, line 52 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. |
| 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 540 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 552 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 256 def add_element element=nil, attrs=nil el = @elements.add(element) if attrs.kind_of? Hash attrs.each do |key, value| el.attributes[key]=value if key =~ /^xmlns:/ end attrs.each do |key, value| el.attributes[key]=value if key !~ /^xmlns:/ end end 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 211 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 488 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 508 def attribute( name, namespace=nil ) prefix = '' if namespace prefix = attributes.prefixes.each { |prefix| return "#{prefix}:" if namespace( prefix ) == namespace } || '' end attributes.get_attribute( "#{prefix}#{name}" ) 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 74 def clone Element.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 573 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 280 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 231 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 93 def document root.parent if root end
Synonym for Element.elements.each
# File rexml/element.rb, line 357 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 315 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 itterate 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 346 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 426 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 520 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 289 def has_elements? !@elements.empty? end
# File rexml/element.rb, line 122 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
Get an array of all Instruction children. IMMUTABLE
# File rexml/element.rb, line 596 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 183 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 163 def namespaces namespaces = [] namespaces = parent.namespaces if parent namespaces |= 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 374 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 156 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 385 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 139 def raw @raw = (@context and @context[:raw] and (@context[:raw] == :all or @context[:raw].include? expanded_name)) @raw end
Evaluates to the root element 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.
d = Document.new '<a><b><c/></b></a>' a = d[1] ; c = a[1][1] d.root # These all evaluate to the same Element, a.root # namely, <a> c.root #
# File rexml/element.rb, line 87 def root parent.nil? ? self : parent.root 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 415 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 457 def text=( text ) if text.kind_of? String text = Text.new( text, whitespace(), nil, raw() ) elsif text 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
Evaluates to true if whitespace is respected for this element. This is the case if:
The evaluation is tested against expanded_name, and so is namespace sensitive.
# File rexml/element.rb, line 106 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( $stdout ) #-> doc written to the console
# File rexml/element.rb, line 628 def write(writer=$stdout, indent=-1, transitive=false, ie_hack=false) #print "ID:#{indent}" writer << "<#@expanded_name" @attributes.each_attribute do |attr| writer << " " attr.write( writer, indent ) end unless @attributes.empty? if @children.empty? if transitive and indent>-1 writer << "\n" indent( writer, indent ) elsif ie_hack writer << " " end writer << "/" else if transitive and indent>-1 and !@children[0].kind_of? Text writer << "\n" indent writer, indent+1 end writer << ">" write_children( writer, indent, transitive, ie_hack ) writer << "</#{expanded_name}" end if transitive and indent>-1 and !@children.empty? writer << "\n" indent -= 1 if next_sibling.nil? indent(writer, indent) end writer << ">" end