File indexing completed on 2024-11-03 03:45:45

0001 /*
0002     This file is part of the syndication library
0003     SPDX-FileCopyrightText: 2006 Frank Osterfeld <osterfeld@kde.org>
0004 
0005     SPDX-License-Identifier: LGPL-2.0-or-later
0006 */
0007 
0008 #ifndef SYNDICATION_RDF_NODEVISITOR_H
0009 #define SYNDICATION_RDF_NODEVISITOR_H
0010 
0011 #include <QSharedPointer>
0012 
0013 #include "../syndication_export.h"
0014 
0015 namespace Syndication
0016 {
0017 namespace RDF
0018 {
0019 //@cond PRIVATE
0020 class Literal;
0021 typedef QSharedPointer<Literal> LiteralPtr;
0022 class Node;
0023 typedef QSharedPointer<Node> NodePtr;
0024 class Property;
0025 typedef QSharedPointer<Property> PropertyPtr;
0026 class Resource;
0027 typedef QSharedPointer<Resource> ResourcePtr;
0028 class Sequence;
0029 typedef QSharedPointer<Sequence> SequencePtr;
0030 //@endcond
0031 
0032 /**
0033  * Visitor interface, following the Visitor design pattern. Use this if you
0034  * want to process nodes and the way how to handle the nodes depends
0035  * on it's concrete type (e.g. Resource or Literal).
0036  *
0037  * TODO: insert code example
0038  *
0039  * @author Frank Osterfeld
0040  */
0041 class NodeVisitor // krazy:exclude=dpointer
0042 {
0043 public:
0044     /**
0045      * destructor
0046      */
0047     virtual ~NodeVisitor();
0048 
0049     /**
0050      * call this method to handle a node. Depending on the concrete type
0051      * of the node, a specialized visit method is called.
0052      *
0053      * @param node the node to process
0054      */
0055     virtual void visit(NodePtr node);
0056 
0057     /**
0058      * reimplement this method to handle literals.
0059      *
0060      * @param item the literal to visit
0061      * @return whether the visitor handled the literal.
0062      * Reimplementations of this method must return @p true.
0063      */
0064     virtual bool visitLiteral(LiteralPtr);
0065 
0066     /**
0067      * reimplement this method to handle nodes that weren't handled
0068      * by the more specific method.
0069      *
0070      * @param node the node to visit
0071      * @return whether the visitor handled the node.
0072      * Reimplementations of this method must return @p true.
0073      */
0074     virtual bool visitNode(NodePtr node);
0075 
0076     /**
0077      * reimplement this method to handle properties.
0078      *
0079      * @param property the property to visit
0080      * @return whether the visitor handled the property.
0081      * Reimplementations of this method must return @p true.
0082      */
0083     virtual bool visitProperty(PropertyPtr property);
0084 
0085     /**
0086      * reimplement this method to handle resources.
0087      *
0088      * @param resource the resource to visit
0089      * @return whether the visitor handled the resource.
0090      * Reimplementations of this method must return @p true.
0091      */
0092     virtual bool visitResource(ResourcePtr resource);
0093 
0094     /**
0095      * reimplement this method to handle sequences.
0096      *
0097      * @param seq the sequence to visit
0098      * @return whether the visitor handled the sequence.
0099      * Reimplementations of this method must return @p true.
0100      */
0101     virtual bool visitSequence(SequencePtr seq);
0102 };
0103 
0104 } // namespace RDF
0105 } // namespace Syndication
0106 
0107 #endif // SYNDICATION_RDF_NODEVISITOR_H