1 /*
2  * This library is free software; you can redistribute it and/or
3  * modify it under the terms of the GNU Lesser General Public
4  * License as published by the Free Software Foundation; either
5  * version 2.1 of the License, or (at your option) any later version.
6  *
7  * As a special exception, you may use this file as part of a free
8  * software library without restriction. Specifically, if other files
9  * instantiate templates or use macros or inline functions from this
10  * file, or you compile this file and link it with other files to
11  * produce an executable, this file does not by itself cause the
12  * resulting executable to be covered by the GNU General Public
13  * License. This exception does not however invalidate any other
14  * reasons why the executable file might be covered by the GNU Library
15  * General Public License.
16  *
17  * This library is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20  * Lesser General Public License for more details.
21  *
22  * You should have received a copy of the GNU Lesser General Public
23  * License along with this library; if not, write to the Free Software
24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
25  */
26 #ifndef cxxtools_Xml_Node_h
27 #define cxxtools_Xml_Node_h
28 
29 #include <cxxtools/xml/api.h>
30 
31 namespace cxxtools {
32 
33     namespace xml {
34 
35         /**
36          * @brief The super-class for all specific Node type of an XML document.
37          *
38          * A Node may for example be a opening tag, a closing tag, a comment or a doctype declaration.
39          * The supported node types are contained in the enum Type. To determine the type of a Node the
40          * method type() can be used.
41          *
42          * For every supported node type (except "Unknown") a specialized class exists that is derived
43          * from this Node class. Those classes contain more data and access methods to allow the user
44          * to determine the information specific to the node, for example the tag name for a StartElement.
45          *
46          * This class mainly provides the method type() to determine the type of the Node. The user
47          * may use this information to determine to which specialized class that is associated
48          * with the type this object can be cast; for the Node::StartElement type the Node object can be
49          * cast to StartElement, for example.
50          *
51          * @see Type
52          */
53         class CXXTOOLS_XML_API Node {
54             public:
55                 enum Type {
56                     //! Unknown Node type (may not currently be supported)
57                     Unknown = 0,
58                     //! Xml declaration (see class XmlDeclaration)
59                     StartDocument = 1,
60                     //! Doctype (see class DocType)
61                     DocType = 2,
62                     //! End of the document (see EndDocument)
63                     EndDocument = 3,
64                     //! Start element aka opening tag (see StartElement)
65                     StartElement = 4,
66                     //! End element aka closing tag (see EndElement)
67                     EndElement = 5,
68                     //! Parsed content of a tag's body (see Characters)
69                     Characters = 6,
70                     //! Comment (see Comment)
71                     Comment,
72                     //! Processing instruction (see ProcessingInstruction)
73                     ProcessingInstruction
74                 };
75 
76             public:
77                 /**
78                  * @brief Constructs a new Node object with the specified node type
79                  * @see Type
80                  */
Node(Type type)81                 Node(Type type)
82                 : _type(type)
83                 { }
84 
85                 //! Empty destructor
~Node()86                 virtual ~Node()
87                 { }
88 
89                 /**
90                  * @brief Returns the type of this Node that can be used to determine what specific
91                  * Node this object is.
92                  *
93                  * This information may be used to determine to which specialized Node class that is associated
94                  * with the type, this Node object can be cast; for the Node::StartElement type the Node object
95                  * can be cast to StartElement, for example.
96                  *
97                  * @return The type of this node.
98                  */
type()99                 Type type() const
100                 {return _type;}
101 
102                 /**
103                  * @brief Compares this Node object with the given node.
104                  *
105                  * The return value of the generic operator== method is always false. Class which derive
106                  * from this class should always override this method and provide a useful comparison, for
107                  * example by comparing the node type and contents of the current and given Node object
108                  *
109                  * @param node In subclasses this Node object is compared to the current Node object.
110                  * @return In sub-classes $true is returned if this Node object is the same as the given
111                  * Node object. In this generic class $false$ is always returned.
112                  */
113                 virtual bool operator==(const Node& node) const
114                 { return false; }
115 
116                 virtual Node* clone() const = 0;
117 
118             private:
119                 //! The type of this Node.
120                 Type _type;
121         };
122 
123     }
124 
125 }
126 
127 #endif
128