Community Core Vision

//

// Attr.h

//

// $Id: //poco/1.3/XML/include/Poco/DOM/Attr.h#1 $

//

// Library: XML

// Package: DOM

// Module:  DOM

//

// Definition of the DOM Attr class.

//

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

// and Contributors.

//

// Permission is hereby granted, free of charge, to any person or organization

// obtaining a copy of the software and accompanying documentation covered by

// this license (the "Software") to use, reproduce, display, distribute,

// execute, and transmit the Software, and to prepare derivative works of the

// Software, and to permit third-parties to whom the Software is furnished to

// do so, all subject to the following:

// 

// The copyright notices in the Software and this entire statement, including

// the above license grant, this restriction and the following disclaimer,

// must be included in all copies of the Software, in whole or in part, and

// all derivative works of the Software, unless such copies or derivative

// works are solely in the form of machine-executable object code generated by

// a source language processor.

// 

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT

// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE

// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,

// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

// DEALINGS IN THE SOFTWARE.

//

#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