//

// Attr.h

//

// Library: XML

// Package: DOM

// Module:  DOM

//

// Definition of the DOM Attr class.

//

// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.

// and Contributors.

//

// SPDX-License-Identifier: BSL-1.0

//

#ifndef DOM_Attr_INCLUDED

#define DOM_Attr_INCLUDED

#include "Poco/XML/XML.h"

#include "Poco/DOM/AbstractNode.h"

#include "Poco/DOM/Element.h"

#include "Poco/XML/Name.h"

namespace Poco {

namespace XML {

class XML_API Attr: public AbstractNode

  /// 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.

{

public:

  const XMLString& name() const;

    /// Returns the name of this attribute.

  bool specified() const;

    /// 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.

    ///     * If the attribute is not associated to any element (i.e. because it

    ///       was just created or was obtained from some removal or cloning operation)

    ///       specified is true.

  const XMLString& value() const;

    /// Returns the value of the attribute as a string. Character

    /// and general entity references are replaced with their values. See also the

    /// method getAttribute on the Element interface.

  const XMLString& getValue() const;

    /// Returns the value of the attribute as a string. Character

    /// and general entity references are replaced with their values. See also the

    /// method getAttribute on the Element interface.

  void setValue(const XMLString& value);

    /// Sets the value of the attribute as a string.

    /// This creates a Text node with the unparsed contents of the string.

    /// I.e. any characters that an XML processor would recognize as markup are

    /// instead treated as literal text. See also the method setAttribute on the

    /// Element interface.

  // DOM Level 2

  Element* ownerElement() const;

    /// The Element node this attribute is attached to or null

    /// if this attribute is not in use.

  // Node

  Node* parentNode() const;

  const XMLString& nodeName() const;

  const XMLString& getNodeValue() const;

  void setNodeValue(const XMLString& value);

  unsigned short nodeType() const;

  Node* previousSibling() const;

  const XMLString& namespaceURI() const;

  XMLString prefix() const;

  const XMLString& localName() const;

  // Non-standard extensions

  XMLString innerText() const;

protected:

  Attr(Document* pOwnerDocument, Element* pOwnerElement, const XMLString& namespaceURI, const XMLString& localName, const XMLString& qname, const XMLString& value, bool specified = true);

  Attr(Document* pOwnerDocument, const Attr& attr);

  ~Attr();

  Node* copyNode(bool deep, Document* pOwnerDocument) const;

private:

  const Name& _name;

  XMLString   _value;

  bool        _specified;

  friend class Document;

  friend class Element;

  friend class DOMBuilder;

};

//

// inlines

//

inline const XMLString& Attr::name() const

{

  return _name.qname();

}

inline const XMLString& Attr::value() const

{

  return _value;

}

inline const XMLString& Attr::getValue() const

{

  return _value;

}

inline bool Attr::specified() const

{

  return _specified;

}

inline Element* Attr::ownerElement() const

{

  return static_cast<Element*>(_pParent);

}

} } // namespace Poco::XML

#endif // DOM_Attr_INCLUDED