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DOM::Attr Class Reference
The Attr
interface represents an attribute in an Element
object.
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#include <dom_element.h>
Inheritance diagram for DOM::Attr:
List of all members.
Detailed Description
The Attr
interface represents an attribute in an Element
object.
Typically the allowable values for the attribute are defined in a document type definition.
Attr
objects inherit the Node
interface, but since they are not actually child nodes of the element they describe, the DOM does not consider them part of the document tree. Thus, the Node
attributes parentNode
, previousSibling
, and nextSibling
have a null value for Attr
objects. The DOM takes the view that attributes are properties of elements rather than having a separate identity from the elements they are associated with; this should make it more efficient to implement such features as default attributes associated with all elements of a given type. Furthermore, Attr
nodes may not be immediate children of a DocumentFragment
. However, they can be associated with Element
nodes contained within a DocumentFragment
. In short, users and implementors of the DOM need to be aware that Attr
nodes have some things in common with other objects inheriting the Node
interface, but they also are quite distinct.
The attribute's effective value is determined as follows: if this attribute has been explicitly assigned any value, that value is the attribute's effective value; otherwise, if there is a declaration for this attribute, and that declaration includes a default value, then that default value is the attribute's effective value; otherwise, the attribute does not exist on this element in the structure model until it has been explicitly added. Note that the nodeValue
attribute on the Attr
instance can also be used to retrieve the string version of the attribute's value(s).
In XML, where the value of an attribute can contain entity references, the child nodes of the Attr
node provide a representation in which entity references are not expanded. These child nodes may be either Text
or EntityReference
nodes. Because the attribute type may be unknown, there are no tokenized attribute values.
Constructor & Destructor Documentation
DOM::Attr::Attr |
( |
const Node & |
other |
) |
[inline] |
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DOM::Attr::Attr |
( |
const Attr & |
other |
) |
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DOM::Attr::Attr |
( |
AttrImpl * |
_impl |
) |
[protected] |
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Member Function Documentation
Attr& DOM::Attr::operator= |
( |
const Node & |
other |
) |
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Attr& DOM::Attr::operator= |
( |
const Attr & |
other |
) |
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Returns the name of this attribute.
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bool DOM::Attr::specified |
( |
|
) |
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If this attribute was explicitly given a value in the original document, this is true ; otherwise, it is false .
Note that the implementation is in charge of this attribute, not the user. If the user changes the value of the attribute (even if it ends up having the same value as the default value) then the specified flag is automatically flipped to true . To re-specify the attribute as the default value from the DTD, the user must delete the attribute. The implementation will then make a new attribute available with specified set to false and the default value (if one exists).
In summary:
- If the attribute has an assigned value in the document then
specified is true , and the value is the assigned value.
- If the attribute has no assigned value in the document and has a default value in the DTD, then
specified is false , and the value is the default value in the DTD.
- If the attribute has no assigned value in the document and has a value of IMPLIED in the DTD, then the attribute does not appear in the structure model of the document.
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On retrieval, the value of the attribute is returned as a string.
Character and general entity references are replaced with their values.
On setting, this creates a Text node with the unparsed contents of the string. |
void DOM::Attr::setValue |
( |
const DOMString & |
|
) |
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Element DOM::Attr::ownerElement |
( |
|
) |
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Introduced in DOM Level 2.
The Element node this attribute is attached to or null if this attribute is not in use. |
Friends And Related Function Documentation
friend class Element [friend]
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friend class Document [friend]
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friend class DocumentImpl [friend]
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friend class HTMLDocument [friend]
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friend class ElementImpl [friend]
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friend class NamedAttrMapImpl [friend]
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friend class AttrImpl [friend]
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The documentation for this class was generated from the following file:
Generated on Sat Jan 31 23:28:25 2004 for XPath by
1.2.18