REXML::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.

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.

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[name].

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/>

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'/>

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"] ] )

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

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'/>

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.

Get an array of all CData children. IMMUTABLE

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/>"

Get an array of all Comment children. IMMUTABLE

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/>

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

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/>

Evaluates to the document to which this element belongs, or nil if this element doesn’t belong to a document.

Synonym for Element.elements.each

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}

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}

A private helper method

Synonym for Element.to_a This is a little slower than calling elements.each directly.

xpath

any XPath by which to search for elements in the tree

Returns

an array of Elements that match the supplied path

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 "

Evaluates to true if this element has any attributes set, false otherwise.

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

Evaluates to true if this element has at least one Text child

Get an array of all Instruction children. IMMUTABLE

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.

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'

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

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']

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

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.

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

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 "

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>'

Get an array of all Text children. IMMUTABLE

Evaluates to true if whitespace is respected for this element. This is the case if:

1. Neither :respect_whitespace nor :compress_whitespace has any value

2. 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.

DEPRECATED

See REXML::Formatters

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

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